Professional Psychology: Research and Practice Copyright 2007 by the American Psychological Association

2007, Vol. 38, No. 4, 411– 420 0735-7028/07/$12.00 DOI: 10.1037/0735-7028.38.4.411

The “Chemical Imbalance” Explanation for Depression:

Origins, Lay Endorsement, and Clinical Implications

Christopher M. France Paul H. Lysaker

Cleveland State University Roudebush Veterans Affairs Medical Center, Indianapolis, and
Indiana University School of Medicine

Ryan P. Robinson
University of Akron
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
This document is copyrighted by the American Psychological Association or one of its allied publishers.

When a client asks whether her or his depression is caused by a chemical imbalance, how do you
respond? Depression is regularly depicted in popular media as resulting from a “chemical imbalance” and
this depiction raises a number of interesting questions for practicing clinicians. How accurate is the
chemical imbalance explanation for depression? How widely do laypersons agree with the explanation,
and how do they interpret the explanation? We discuss the origins, accuracy, and transmittal (e.g., via
direct-to-consumer advertising) of the chemical imbalance explanation for depression. We next present
results from a group case study examining lay endorsement and interpretation of the explanation. Finally,
we discuss clinical implications and present a short script for educating clients concerning “chemical
imbalances” in depression.

Keywords: chemical imbalance, depression, laypersons, direct-to-consumer advertising, monoamines

It is common in the United States for depression to be described We do not dispute the possibility that neurotransmitters and
as resulting from a “chemical imbalance” (e.g., Valenstein, 1998). other brain chemicals play a significant role in the etiology of
As the potentially dominant cultural story of depression etiology, depression. However, we are also concerned that the chemical
the chemical imbalance explanation may exert a significant effect imbalance explanation may not reflect the full range of causes of
on treatment-seeking behaviors as well as the structures that are depression, may be given greater credence by both consumers and
created and maintained for such treatment (e.g., Smith, 1999; also practitioners than is supported by sound research, and/or may be
see Rothman, 1971). As such, it appears important for mental understood in an overly simplistic manner. Any unitary under-
health professionals and other stakeholders (e.g., policymakers) to standing of human suffering asserted in isolation of its nuances
understand lay beliefs concerning chemical imbalance explana- may mislead those in need of treatment and confound self-
tions for depression. understanding, resulting in treatment-seeking strategies and out-
comes that are less than optimal for at least some clients.
CHRISTOPHER M. FRANCE received his PsyD in clinical psychology from
Wright State University. He is an assistant psychology professor at Cleve- The Development of Chemical Imbalance Explanations
land State University and a licensed psychologist. His research interests
for Depression
include cultural and personal conceptions of mental disorders and their
treatment. Modern chemical imbalance hypotheses of depression origi-
PAUL H. LYSAKER received his PhD in clinical psychology from Kent State nated in the mid-20th century, spurred by important discoveries
University. He is a staff clinical psychologist at the Roudebush Veterans
such as the efficacy of chlorpromazine for psychosis; findings that
Affairs Medical Center, Day Hospital 116H, and an assistant clinical
professor of psychology at the Indiana University School of Medicine,
monoamines exist within the central nervous system (CNS) and act
Department of Psychiatry. His major areas of interest include vocational as neurotransmitters; and an early understanding of monoamine
rehabilitation, personal narratives, and recovery from severe mental illness. synthesis, storage, release, and deactivation. Such discoveries also
RYAN P. ROBINSON received his MA in industrial organizational psychol- quickened the emergence of psychopharmacology as a discipline
ogy from the University of Akron, where he is also a doctoral candidate in and helped lead to the eventual widespread practice of using
industrial organizational psychology. He is also a part-time lecturer at prescription drugs to treat mental disorders also (e.g., Healy,
Cleveland State University. His areas of interest include employee training 2001).
and development, affective reactions in the workplace, and research meth-
ods and statistics.
WE THANK Heather Dukes for assisting with background research and data Iproniazid and Imipramine
organization.
CORRESPONDENCE CONCERNING THIS ARTICLE should be addressed to Chris- The 1950s saw the appearance of the first antidepressant drugs
topher M. France, Department of Psychology, Cleveland State University, of the modern era, two being iproniazid and imipramine (Healy,
Chester Building 159, 2121 Euclid Avenue, Cleveland, OH 44115. E-mail: 1997). Iproniazid’s initial importance was as an effective tubercu-
c.m.france@csuohio.edu losis treatment, but it was also noted that some tubercular patients

411
 412 FRANCE, LYSAKER, AND ROBINSON

taking the drug experienced psychostimulation and euphoria. Fol- amines noradrenaline, dopamine, and serotonin (Healy, 1997).
lowing such observations, the drug was tested on a variety of Some effective tuberculosis drugs were known to inhibit MAO’s
psychiatric patients in and outside the United States (Baumeister, effects, and iproniazid (the tuberculosis drug turned antidepres-
Hawkins, & Uzelac, 2003; Crane, 1957). In one early study, sant) was found to be a potent MAO inhibitor (MAOI). Impor-
iproniazid was given to 17 institutionalized female patients who tantly, iproniazid was further found to block the behavioral effects
were “withdrawn, regressed, . . . and of flattened affect” (Loomer, of reserpine, presumably by slowing the oxidation of serotonin
Saunders, & Kline, 1957, p. 133). Of the 17 patients, 70% “showed depleted from presynaptic stores via reserpine. In turn, this would
at least some favorable response” (p. 137) after 5 months of allow more serotonin to reach and be released at neural synapses.
iproniazid treatment. The same authors also reported the successful It is at this point—that is, where serotonin depletion via reser-
use of iproniazid with a small sample of depressed outpatients pine leads to depression, and where such symptoms are thought to
(Loomer et al., 1957). Such results were widely publicized, and be blocked by the (serotonin-enhancing MAOI) antidepressant
iproniazid became (for several years, until its withdrawal from the iproniazid—that a serotonin deficit hypothesis of depression be-
market because of potentially serious side effects) a popular treat- comes possible. Reserpine was later found to also deplete the
ment for depression (Healy, 2001). catecholamines, making it possible (as the MAOIs such as ipro-
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
This document is copyrighted by the American Psychological Association or one of its allied publishers.

Imipramine resulted from a conscious attempt to replicate the niazid also inhibit catecholamine oxidation) to expand a potential
success of chlorpromazine, the first widely used antipsychotic serotonin deficit model of depression to include the cat-
drug. Chemists at Geigy derived a number of drugs (including echolamines. Such monoamine deficiency theories were buttressed
imipramine) from iminodibenzyl, a compound with a (tricyclic) by later findings that imipramine also increased the synaptic avail-
central molecular structure resembling that of chlorpromazine ability of certain monoamines (primarily serotonin and norepi-
(Healy, 1997). Imipramine was found ineffective as a neuroleptic nephrine) by blocking their uptake into presynaptic terminal but-
in one early, large-scale study; however, a later review of nursing tons (Glowinski & Axelrod, 1964; also see Pletscher, 1991).
notes suggested some patients had experienced elevated moods Though previous authors (e.g., see Brodie & Shore, 1957) had
during the trial (Healy, 2001). This observation justified a trial of speculated that low monoamine levels could cause depressive
imipramine with a sample of about 40 depressed (rather than states and that increasing monoamines might reduce depression,
psychotic) patients. Roland Kuhn (1958), a psychiatrist who was Schildkraut (1965) is often credited with the first clear statement of
involved in the above studies and who also used imipramine the catecholamine hypothesis of depression, and Coppen (1967) is
extensively in the clinical setting, concluded that imipramine was often credited with developing the serotonin hypothesis of depres-
quite effective as a treatment for depression. Imipramine was sion. Regardless of how credit is allocated, such “imbalance”
marketed in the United States beginning in 1958 (Healy, 2001). theories (i.e., the monoamine hypothesis) have played a dominant
role for the past 40 years or so in guiding research aimed at
Reserpine’s Role understanding the biological bases of depression and developing
pharmacological treatments for the same (e.g., Hindmarch, 2002).
The 1950s also saw investigations of the properties of reserpine,
an alkaloid derived from the root of Rauwolfia serpentina. The How Accurate Are Chemical Imbalance Explanations of
root caught the attention of U.S. researchers because of its use in Depression?
India as an herbal treatment for hypertension and psychosis
(Healy, 1997). Reserpine was initially marketed in the United
Response to and Efficacy of Antidepressants
States as a sedative and antihypertensive drug (Baumeister et al., Multiple findings (e.g., Masand & Gupta, 1999; Kessler et al.,
2003), with Nathan Kline (e.g., Barsa & Kline, 1956) being among 2003) that antidepressants (which typically increase monoamine
the first in the United States to document its effects on psychiatric levels) reduce depressive symptoms have been seen as abundant
symptoms. Reserpine was found to have clear sedating as well as support for the chemical imbalance explanation of depression.
moderate neuroleptic effects. Though used rather frequently as a However, response to antidepressants is not by itself proof that an
neuroleptic in the 1950s, reserpine never achieved chlorproma- imbalance of brain chemicals causes depression. Psychotherapy
zine’s popularity and is rarely used today as a neuroleptic. can alleviate depression (e.g., Antonuccio, Danton, DeNelsky,
Reserpine did, however, play a significant role in the develop- Greenberg, & Gordon, 1999); therefore (using the above logic), a
ment of chemical imbalance theories of depression. Serotonin had deficiency of psychotherapy causes depression (of course, we are
been found in animal studies (e.g., Bogdanski, Weissbach, & unaware of any serious assertions to this effect).
Udenfriend, 1958) to exist in the CNS and to have activating Also interfering with response-equals-causation logic are find-
effects on behavior. Reserpine was found to deplete brain seroto- ings that in many clinical trials, antidepressants have exhibited
nin stores, and it was hypothesized that reserpine’s characteristic either no or very modest advantages in comparison with placebos
(depressive-like) effects of sedation and lethargy were due to such (Kirsch, Moore, Scoboria, & Nicholls, 2002; Kirsch, Scoboria, &
serotonin depletion (e.g., Shore, Silver, & Brodie, 1955). Reser- Moore, 2002). Such findings raise the possibility that antidepres-
pine also acquired a reputation (in retrospect likely undeserved) as sants may often act as active placebos rather than having unique
depressogenic for humans after it was reported in multiple papers and specific antidepressant properties. As well, note that mono-
(see Baumeister et al., 2003, for a review) that patients taking the amine enhancers are not the only drugs found effective for depres-
drug for hypertension tended to develop depressive symptoms. sion; for example, tianeptine is an effective antidepressant (Wag-
Previous research focused on the inactivation of adrenaline led staff, Ormrod, & Spencer, 2001) that lowers serotonin levels in the
to the discovery of an enzyme, now known as monoamine oxidase brain by enhancing rather than slowing presynaptic serotonin
(MAO), that oxidized not only adrenaline, but also the mono- uptake.
 CHEMICAL IMBALANCE EXPLANATION FOR DEPRESSION 413

The above studies do not directly test chemical imbalance free amino acid drink; these methods prevent the synthesis of
explanations of depression but do provide information relevant to serotonin by depleting its precursor, tryptophan (Delgado, 2000,
the accuracy of such claims. If depression can be reduced via 2004). Norepinephrine and dopamine production are reversibly
multiple means such as medication, placebo responses, psycho- inhibited via the administration of alpha-methyl-para-tyrosine
therapy, exercise (e.g., Babyak et al., 2000), and so forth, then (AMPT; see Delgado, 2000, for details).
perhaps depression is multicausal and multifactorial in nature In a number of studies, some but not all patients in remission
rather than resulting solely or primarily from an imbalance of brain from depression via antidepressants have experienced a transient
chemicals. If so, it would appear appropriate for clinicians to return of symptoms during monoamine depletions (e.g., Delgado et
educate their patients as to such multiple causes of, and multiple al., 1990, 1993; Miller, Delgado, Salomon, Berman, et al., 1996).
effective treatments for, depression. A consistent finding has been that participants in remission via
selective serotonin reuptake inhibitors (SSRIs)—these boost sero-
Measurements of Monoamines and Their Metabolites in tonin levels—are more likely to experience a return of symptoms
when serotonin is depleted (e.g., Delgado et al., 1999; Delgado &
Depression
Moreno, 1999; Salomon, Miller, Delgado, & Charney, 1993).
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
This document is copyrighted by the American Psychological Association or one of its allied publishers.

Consistent findings of low monoamine levels in depressed per- Conversely, those in remission via norepinephrine reuptake inhib-
sons might also be looked to as support for chemical imbalance itors are more likely to experience a return of symptoms during
theories of depression etiology. Monoamines and/or their metab- (AMPT-induced) reductions of norepinephrine (e.g., Delgado,
olites can be measured within the cerebrospinal fluid (CSF), blood 2000). Monoamine depletion has also been found to induce tran-
plasma and platelets, urine, extracellular brain fluid, or postmor- sient depressive symptoms in about 60% of remitted, (now)
tem brain slices (e.g., see Gjerris, 1988). Direct brain measure- medication-free subjects (Neumeister et al., 2004) as well as some
ments of monoamines are typically accomplished by using animals healthy subjects with a strong family (but no personal) history of
(e.g., Bianchi, Moser, Lazzarini, Vecchiato, & Crespi, 2002) or affective illness (Benkelfat, Ellenbogen, Dean, Palmour, & Young,
postmortem brains (either human or animal). A primary metabolite 1994; Klaassen et al., 1999).
of serotonin is 5-hydroxyindoleacetic acid (5-HIAA), and However, a number of findings from monoamine depletion
3-methoxy-4-hydroxyphenylglycol (MHPG) is a major norepi- studies contradict a simplistic or universal chemical imbalance
nephrine metabolite (Delgado, 2000). theory of depression. First, even when type of monoamine deple-
Lowered monoamine/metabolite levels have indeed been found tion is matched to antidepressant response (e.g., serotonin deple-
in some depressed groups. For example, Asberg, Thoren, Trask- tion in SSRI responders), fairly high numbers of subjects experi-
man, Bertilsson, and Ringberger (1976) found levels of CSF ence either no or only mild exacerbation of symptoms (e.g., see
5-HIAA correlated with severity of depression in some depressed Booij et al., 2002). Next, monoamine depletion does not typically
patients. Sedvall et al. (1980) found lowered CSF 5-HIAA levels exacerbate symptoms in medication-free depressed patients (e.g.,
in normal controls with a family history of depression and sug- Delgado, 2000). An important finding is that monoamine depletion
gested CSF 5-HIAA levels might act as a marker of genetic does not typically induce depressive symptoms in healthy subjects
vulnerability for depression. Asberg et al. (1984) found lowered without a history of depression (Booij et al., 2002; Delgado &
levels of CSF 5-HIAA in patients with melancholia in comparison Moreno, 1999), even in cases where both serotonin and norepi-
with nondepressed controls. nephrine are simultaneously depleted (Salomon, Miller, Krystal,
However, such findings have been far from consistent. In mul- Heninger, & Charney, 1997). Monoamine depletion studies have
tiple studies conducted in the 1960s through the 1980s (see Gjerris, been important in suggesting serotonin and norepinephrine play a
1988, for a review), there was little evidence that monoamine role in depression and antidepressant response for at least some
levels could be reliably linked to depression. Recent studies fo- patients; furthermore, such research might lead to biological mark-
cusing primarily on serotonin and norepinephrine have often found ers predicting vulnerability to depression and/or specific antide-
normal levels (i.e., similar to those seen in nondepressed controls) pressant response (e.g., Berman et al., 1999; Booij et al., 2002).
of such transmitters and their metabolites in depressed persons However, as stated succinctly by Miller, Delgado, Salomon,
(e.g., see Delgado, 2000). A logical conclusion from the above Heninger, and Charney (1996), “monoamine deficiency by itself is
findings is that some depressed persons may exhibit lowered insufficient explanation of the cause of depression” (p. 151).
monoamine levels whereas others do not. Furthermore, the exis-
tence of positive findings does not establish a temporal or causal So Where Do We Stand Today?
relationship; that is, the lowered monoamine levels found in some
studies may be a result rather than a cause of depression or may In sum, the pathophysiology of depression remains poorly un-
simply reflect a correlation that is not particularly meaningful with derstood (Hindmarch, 2001; Hirschfeld, 2000), and a simplistic
respect to depression etiology. chemical imbalance explanation for depression likely lacks ade-
quate validity (Hindmarch, 2002). Monoamine deficiencies con-
Monoamine Depletion Studies tinue to be mentioned by some researchers as a potential cause of
depression (e.g., Bianchi et al., 2002), but others have declared
Monoamine depletion studies appear to most directly test chem- simply that the monoamine hypothesis “is incorrect” (Owens,
ical imbalance hypotheses of depression. Here, CNS monoamine 2004, p. 6). Researchers have increasingly turned toward investi-
levels are transiently reduced and then restored, and the effects of gations of other potential biological causes of depression (e.g.,
such changes on mood are measured. Serotonin is depleted via Hindmarch, 2001; Leonard, 2000; McEwen, 1999). Related efforts
short-term dietary restrictions and administration of a tryptophan- to identify distinct brain changes before, during, and after depres-
 414 FRANCE, LYSAKER, AND ROBINSON

sion treatment are also ongoing (e.g., Cook et al., 2005; Sheline, antidepressants (accounting for at least 70% of worldwide antide-
2003). However, there are currently no widely available anatom- pressant sales), and U.S. consumers spent over $12.5 billion on
ical, chemical, or other biological tests that reliably distinguish the antidepressant drugs in 2001 (National Institute for Health Care
brains of depressed persons from nondepressed persons (e.g., Management, 2002).
Antonuccio et al., 1999). Multiple etiological models (including
biological, environmental, and interactional) of depression remain History of DTC Advertising in the United States
viable at present.
Prescription drug advertising in the United States was limited
The Chemical Imbalance Explanation as Cultural almost entirely to physicians until about 1981, when some print
Narrative advertisements targeted toward consumers began to appear
(Palumbo & Mullins, 2002). This development prompted the U.S.
Despite its flaws, the chemical imbalance explanation remains Food and Drug Administration (FDA) to request a voluntary
the potentially dominant cultural story of depression etiology in moratorium on such ads so that it could consider the implications
the United States (e.g., Smith, 1999). However, cultural narratives of the same. In 1985, the FDA clarified that existing regulations
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
This document is copyrighted by the American Psychological Association or one of its allied publishers.

of mental illness do not necessarily reflect an objective reality or governing prescription drug advertising provided adequate safe-
universal understanding. Different historical and cultural traditions guards and thus did not need to be changed for advertisements
frame depressive experiences within different contexts, thereby targeted at consumers. The regulations required the inclusion of
promoting and/or limiting particular symptoms and shaping dif- large amounts of information within the ads (see Palumbo &
ferent understandings and meanings of depression and its appro- Mullins, 2002, for a detailed discussion of the “brief summary,”
priate treatment. Such narratives are probably best conceptualized “fair balance,” and related provisions), but this could be accom-
as social constructions that must be understood within the cultural plished without excess difficulty by using one or two pages of
context that socializes, interprets, and responds to them (Marsella print. Print advertisements of prescription medications targeted at
& Kaplan, 2002). consumers thus expanded rapidly beginning in the mid-1980s
One goal of our study was to begin to develop data concerning (Grow et al., 2006).
U.S. laypersons’ endorsement and interpretation of the chemical Television advertising of prescription drugs was not easily ac-
imbalance explanation for depression. We hypothesized in part complished in the 1980s and early 1990s because the amount of
that U.S. laypersons would report high levels of exposure to and information required for DTC ads did not fit easily within a
endorsement of chemical imbalance explanations for depression. 30-second television commercial (Palumbo & Mullins, 2002).
These hypotheses were based on certain practices, relatively However, in 1997 (in draft form) and 1999 (in final form) the FDA
unique to the United States, that might lead U.S. cultural narratives released guidance statements concerning acceptable consumer-
of depression etiology and treatment to differ from those seen in directed broadcast ads for prescription drugs. The guidelines stated
many other countries of the world. that DTC broadcast ads must include a “major statement” of risks
and make “adequate provisions” for consumers to obtain the
Direct-to-Consumer Advertising as an Influence on FDA-approved product labeling information for the specific drug.
Cultural Narratives of Depression The major statement provision can be met by disclosing the
product’s major risks in the audio or visual portion of the adver-
To elaborate, note that the United States is one of only two tisement. The adequate provision requirement can be met by
developed nations (New Zealand being the other) that explicitly including several mechanisms (a toll-free telephone number, Web
allow direct-to-consumer (DTC) advertising of prescription drugs page address, and existing print advertisement) whereby a con-
(Grow, Park, & Han, 2006). Such advertising is transmitted via a sumer can access the product labeling information and a statement
variety of means, such as broadcast and print advertisements, within the ad that health care providers may provide additional
manufacturers’ Web sites, and even promotional products embla- information. The above guidelines made DTC broadcast advertis-
zoned with a drug’s name. There is considerable evidence that U.S. ing much more feasible and (quickly) much more common in the
laypersons are regularly exposed to and respond to DTC cam- United States beginning in the late 1990s.
paigns touting prescription medications for a variety of conditions Today, three broad categories of DTC advertising of prescrip-
(e.g., Antonuccio, Danton, & McClanahan, 2003). Pharmaceutical tion drugs are common. “Reminder advertisements” call attention
companies have exponentially increased spending on DTC adver- to a drug’s name (e.g., on a promotional pen) but do not provide
tising over the past 15 years, going from expenditures of roughly indications for use or other (e.g., dosage) information. “Help-
$12 million in 1989 (Palumbo & Mullins, 2002) to well over $3 seeking” or “disease-oriented” ads describe the symptoms of a
billion in 2003 (Kravitz et al., 2005). The potential benefits (e.g., condition and encourage consumers to discuss treatment options
educating consumers, increasing help-seeking behaviors) and pit- with a physician but do not mention a specific drug name.
falls (e.g., the potential overuse of unnecessary medications) of “Product-claim” or “indication” ads do provide a drug’s name and
such DTC advertising have been discussed extensively in the its indications and thus must satisfy the brief summary, fair bal-
literature (e.g., Gardner, Mintzes, & Ostry, 2003; Sullivan, 2000). ance, major statement, and adequate provision requirements for
Pharmaceutical companies actively market depression to the print and broadcast ads as described in part above and more fully
U.S. public as a chemical imbalance that antidepressants are able by Palumbo and Mullins (2002).
to fix (e.g., Grow et al., 2006). Such efforts are intense, attributable DTC advertising is ubiquitous today within the United States
at least in part to the large revenues that can result from antide- (Kravitz et al., 2005). The characterization of depression in such
pressant sales. The United States is the world’s largest market for ads as resulting from chemical imbalances has remained relatively
 CHEMICAL IMBALANCE EXPLANATION FOR DEPRESSION 415

consistent (e.g., see Lilly, 2006), even as the monoamine hypoth- on attributions in depression (e.g., Abramson, Metalsky, & Alloy,
esis falls increasingly out of favor. We are interested in how U.S. 1989) to the topics of this article.
laypersons receive, interpret, and respond to such DTC messages;
as well, we are interested in lay views of depression etiology in The Survey
countries where such messages are not commonly seen in popular
media. Participants in this study completed a survey. Copies of the
survey are available from Christopher M. France. Participants
were adult students drawn from several undergraduate psychology
Lay Beliefs (in the United States and Abroad) Concerning classes at a Midwestern university. A wide variety of majors was
the Etiology of Depression represented. Of the 433 students on the class rosters, 262 (60.5%)
participated in the study. The institutional review board of the
It is unclear whether U.S. lay views concerning depression university approved the study. Participants were informed of the
etiology have changed significantly over the past 5–10 years as a general purpose of the study and assured of anonymity; in turn,
result of increases in DTC broadcast ads. Just prior to this phe- they provided informed, written consent to participate. A vignette
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.

nomenon, there was some evidence that U.S. laypersons did indeed
This document is copyrighted by the American Psychological Association or one of its allied publishers.

of an adult male or female suffering from (unipolar) major depres-

view chemical imbalances as one important cause of depression. sion was included in the survey. Christopher M. France presented
Link, Phelan, Bresnahan, Stueve, and Pescosolido (1999; but note the survey in classroom settings, providing each participant with a
that the data were collected in 1996) presented vignettes of de- written copy of the survey and reading each item aloud. We
pressed persons to a representative sample of U.S. adults and selected and maintained an alpha level of .05 across all inferential
found that a majority (72.8%) felt it “somewhat likely” or “very tests.
likely” that a “chemical imbalance in the brain” might have caused
the depression. However, psychosocial factors were also cited
frequently as potential causes of depression, leaving Link et al. to
Demographic Data
conclude that respondents tended to endorse a “multifactored The survey was completed by 262 participants: 156 (59.5%)
explanation . . . not unlike the diathesis-stress perspective adopted were female, 102 (38.9%) were male, and 4 did not note their
by many mental health experts” (p. 1332). This study is the only gender. Average age of participants was 23.6 years (SD ⫽ 7.23),
one we could find that used both a representative sample and with a range from 18 to 58 years. Average full years of education
specifically asked about chemical imbalances as a cause of depres- completed was 13.17 (SD ⫽ 1.29); however, our measure under-
sion. estimated educational level (details are available from Christopher
In contrast to Link et al.’s (1999) findings and subsequent M. France). A total of 155 (59.2%) participants were White, 65
assertions that the chemical imbalance narrative is dominant in the (24.8%) were African American, and the remaining (16%) identi-
United States, laypersons outside the United States have not yet fied as of other or mixed ethnicity or did not answer the item. We
been found to strongly endorse chemical imbalances as a likely asked about annual household income as a measure of socioeco-
cause of depression. For example, in studies conducted in Swit- nomic status (SES): 73 (27.9%) participants lived in lower income
zerland (Lauber, Falcato, Nordt, & Rössler, 2003), Australia (Jorm households ($24,999 or less), 138 (52.7%) lived in middle income
et al., 1997), Germany (Matschinger & Angermeyer, 1996), Great households ($25,000 –$74,999), and 51 (19.5%) lived in upper
Britain (e.g., Furnham & Kuyken, 1991), Ireland (McKeon & income households ($75,000 or above). Fifty respondents (19.1%)
Carrick, 1991), and Turkey (Cirakoglu, Kokdemir, & Demirutku, reported a history of being diagnosed with and/or seeking treat-
2003), laypersons have consistently endorsed psychosocial over ment for depression; rates were higher for women (about 20.6%)
biochemical factors as likely causes of depression. We would note than men (about 15.7%). Such rates of formal diagnosis/treatment
here that such views may change over time (though this is unclear) seeking are higher than expected (e.g., see Kessler et al., 2003,
to the extent that DTC advertising encroaches into areas where it regarding treatment rates); however, the meaning of this finding is
is now ostensibly banned. For example, some DTC advertising is obscured because of a lack of clear operational definitions for the
now seen in European Union countries via satellite broadcasts as elements of the relevant survey item.
well as the Internet (Sullivan, 2000). In Canada, Food and Drug
Act interpretations have softened such that reminder and help-
Spontaneously Generated Causes of Depression
seeking ads are commonplace (Gardner et al., 2003); as well, many
product-claim ads originating in the United States leak into Canada Following presentation of a depression vignette, participants
across their shared border. generated up to five likely causes of depression and then rank-
The study described next explored how one group of U.S. ordered the causes from most likely to least likely to cause de-
laypersons currently view and interpret chemical imbalance expla- pression. A total of 251 participants provided usable responses.
nations of depression. We note here that our study did not assess We generated a list of the top-ranked causes of depression, and
individual personality and cognitive differences that might influ- Christopher M. France and Paul H. Lysaker independently orga-
ence etiological beliefs. For example, a pessimistic explanatory nized these raw data into meaningful, related categories. The
style consisting of relatively internal, stable, and global attribu- separate lists were compared and discussed until agreement was
tions for negative events is a risk factor for depression (Peterson, reached as to the number and types of categories to use to best
Buchanan, & Seligman, 1995), can remain relatively consistent organize the responses. A random sample of 40 surveys was then
over time, and might influence one’s etiological views of depres- selected (using a random numbers table), and Christopher M.
sion. As such, we suggest future studies linking the large literature France and Paul H. Lysaker separately placed the responses into
 416 FRANCE, LYSAKER, AND ROBINSON

the agreed-upon categories. A comparison of results suggested Table 2

good interrater reliability: 39 of 40 (97.5%) responses were cate- Exposure to the Chemical Imbalance Explanation for Depression
gorized in the same way by both authors (Cohen’s kappa ⫽ .97).
As shown in Table 1, participants most often cited chemical Yes No
imbalance as the single most likely cause of depression. However, Seen or heard via the following: n % n %
note that chemical imbalance was cited as the most likely cause of
depression by a minority of respondents (16.3%), with most of the Television 210 88.6 27 11.4
remaining (top-ranked) responses suggesting nonbiological causes Friend/family member/other 161 67.9 76 32.1
acquaintance
of depression. This finding suggests the respondents viewed de- Magazines 152 64.1 85 35.9
pression as potentially having multiple causes, with chemical Books 121 51.1 116 48.9
imbalance being an important biological, but certainly not the Physician or other medical professional 109 46.0 128 54.0
only, potential cause of depression. Psychologist/mental health professional 105 44.3 132 55.7
Radio 88 37.1 149 62.9
Newspapers 73 30.8 164 69.2
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Exposure to the Chemical Imbalance Explanation for

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Note. This item was completed only by those 240 participants (n ⫽ 237
Depression valid responses) who reported previously seeing or hearing depression
described as resulting from a chemical imbalance. Categories are not
Participants were asked if they had previously seen or heard mutually exclusive.
depression described as being caused by a “chemical imbalance”
or “imbalance of chemicals in the brain.” A total of 240 (91.6%)
respondents answered “yes” to the question, and 22 (8.4%) an- Endorsement and Understanding of the Chemical
swered “no.” The “yes” responders were then asked where and Imbalance Metaphor
how they had seen or heard depression described in this manner. We used five Likert-scaled items (see Table 4 for exact word-
As shown in Table 2, participants most often reported receiving the ing) to assess (a) participants’ endorsement of chemical imbalance
chemical imbalance explanation via television (88.6%, n ⫽ 210), as the primary cause of depression and (b) their understanding of
followed by family, friends, or other acquaintances. how brain chemicals might be used by doctors to diagnose and
treat depression. Response choices ranged from 1 (strongly dis-
Likely Cause of Depression (Likert-Type Items) agree) to 5 (strongly agree).
As shown in Table 4, over half (54.2%) of the sample agreed
Participants were presented with Likert-scaled questions, ran- that depression is primarily caused by a chemical imbalance. As
domized as to order, concerning seven possible causes of depres- this finding conflicts with those reported in Table 1, it appears
sion. Wording was as follows: “How likely is it that depression possible that the item’s wording primed or biased respondents
might be caused by (potential cause)?” Responses ranged from 1 toward endorsement. A minority but not inconsequential percent-
(very unlikely) to 5 (very likely). As seen in Table 3, many age of respondents also endorsed beliefs (Items 3 and 4 of Table 4)
respondents (84.7%, n ⫽ 222) viewed chemical imbalance as a that doctors can measure brain chemicals to determine the pres-
potential cause of depression. However, certain psychosocial stres- ence (24%, n ⫽ 63) and severity (22.1%, n ⫽ 58) of depression.
sors were endorsed even more frequently than chemical imbalance To assess whether demographic and personal variables might
as potential causes of depression. Our sample thus again viewed have influenced responses to Table 4 items, we first developed a
chemical imbalance as a primary biological, but clearly not the measure of the degree to which each participant believed doctors
only, potential cause of depression. understand, measure, and manipulate brain chemicals during de-
pression diagnosis and treatment. This measure (scale score) con-
sisted of the average of responses to Items 2–5 of Table 4. As each
item is on a 5-point (1 to 5) scale, the mean scale score was also
Table 1 between 1 and 5 for each participant. Coefficient alpha for the
Spontaneously Generated Possible Causes of Depression (Top- scale was .66.
Ranked Choices) We then performed a 2 ⫻ 3 ⫻ 2 ⫻ 2 analysis of variance
(ANOVA) using gender, SES (low, middle, high), past depression
Top-ranked cause of depression No. of times cited %
diagnosis/treatment seeking (yes/no), and ethnicity (limited to
Chemical imbalance 41 16.3 African American or White status; n ⫽ 220 of 262 total partici-
Death of family member/loved one 37 14.7 pants) as the independent variables and scale score as described
Relationship problems 34 13.5 above as the dependent variable. The four-way interaction term
Money/job problems 33 13.1 was not significant, but the three-way interaction between gender,
Stress 31 12.4
Low self-esteem 28 11.2 SES, and past depression diagnosis/treatment seeking was signif-
Trauma/abuse/other loss 12 4.8 icant, F(2, 194) ⫽ 3.39, p ⬍ .05. In order to interpret this
Heredity/genetic 6 2.4 three-way interaction, we performed separate 2 ⫻ 2 ANOVAs
Failure to reach goals 4 1.6 using gender and past diagnosis/treatment seeking status for each
Other (ⱕ 3 instances each per category) 25 10.0a
of the three SES levels.
Note. There were 251 valid responses to this item. Results indicated a significant 2 ⫻ 2 interaction effect between
a
Combined. gender and past diagnosis/treatment seeking for the middle SES
 CHEMICAL IMBALANCE EXPLANATION FOR DEPRESSION 417

Table 3
How Likely Is It That Depression Might Be Caused by the Following?

Likely Undecided Unlikely

Potential cause n % n % n %

Recent or ongoing stressful circumstances 257 98.1 1 0.4 4 1.5

Difficult childhood experiences 224 85.5 24 9.2 14 5.3
Chemical imbalance 222 84.7 29 11.1 11 4.2
Excess drug/alcohol use 207 79.0 32 12.2 23 8.8
Genetic/inherited problem 162 61.8 38 14.5 62 23.7
One’s own bad character 143 54.6 53 20.2 66 25.2
Virus/infection 70 26.7 58 22.1 134 51.1

Note. Responses were on a 5-point scale ranging from 1 (very unlikely) to 5 (very likely) and are collapsed into
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.

the three categories above for reporting purposes.

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group ($25,000 –$74,999 annual household income) only, F(1, primary cause of depression (Item 1 in Table 4). Results indicated
194) ⫽ 3.70, p ⬍ .05. In order to interpret the interaction effect, we significant differences among the groups, F(3, 265) ⫽ 4.19, p ⬍
performed univariate ANOVAs for each gender. Results indicated .05. Tukey’s post hoc comparisons revealed those who would
a significant main effect for past diagnosis/treatment seeking, F(1, initially seek depression treatment from a medical doctor also
194) ⫽ 4.97, p ⬍ .05, such that medium SES women who had not endorsed chemical imbalance as the primary cause of depression at
been previously diagnosed with or sought depression treatment higher levels (M ⫽ 3.75 for family physician group; M ⫽ 3.56 for
were more likely (mean scale score ⫽ 3.18) to believe that doctors psychiatrist group; p ⬍ .05 for all comparisons) than those who
understand, measure, and manipulate brain chemicals during de- would seek initial treatment from a psychologist/counselor (M ⫽
pression diagnosis and treatment than middle SES women who had 3.35) or religious advisor (M ⫽ 3.17).
been previously diagnosed with or sought treatment for depression
(M ⫽ 2.72). This effect was not found for men, F(1, 194) ⫽ .80, ns. Summary and Implications

Treatment-Seeking Strategies and Endorsement of the The monoamine hypothesis has provided the impetus for nu-
merous important research projects seeking the biological causes
Chemical Imbalance Explanation
of depression and efficacious pharmacological treatments for the
Participants were also asked whom they would contact first if same. However, this chemical imbalance explanation remains un-
seeking professional help for depression, and 260 provided usable proven and is potentially invalid. The significant limitations of the
responses. A total of 115 (44.2%) respondents reported they would imbalance explanation, however, have not prevented U.S. layper-
contact their family physician; 88 (33.8%) reported they would sons (as well as some treating professionals and other stakehold-
contact a psychologist, counselor, or other psychotherapist; 29 ers) from being urged (e.g., via DTC advertisements) to accept the
(11.2%) reported they would contact a religious advisor (e.g., explanation as a likely fact.
pastor, priest, rabbi, and so forth); and 28 (10.8%) reported they The convenience sample used in this study reported widespread
would contact a psychiatrist. We conducted a one-way ANOVA to exposure to the chemical imbalance explanation for depression,
determine whether such treatment preferences (four groups) were most often via television, and many in the sample viewed chemical
related to levels of endorsement of chemical imbalance as the imbalance as a potential or even primary cause of depression. A

Table 4
Endorsement and Understanding of the Chemical Imbalance Explanation for Depression

Agree Undecided Disagree

Statement n % n % n %

1. Depression is primarily caused by an imbalance of 142 54.2 76 29.0 44 16.8

chemicals in the brain.
2. Doctors understand which specific brain chemicals 118 45.0 112 42.8 32 12.2
are involved in causing depression.
3. Doctors can measure levels of brain chemicals to 63 24.0 114 43.5 85 32.4
tell who is depressed and who is not depressed.
4. Doctors are able to measure chemicals in the brain 58 22.1 117 44.7 87 33.2
to determine one’s level of depression.
5. Doctors can fix depression by adding or subtracting 92 35.1 87 33.2 83 31.7
brain chemicals until properly balanced.

Note. Responses were on a 5-point scale ranging from 1 (strongly disagree) to 5 (strongly agree) and are
collapsed into the three categories above for reporting purposes only.
 418 FRANCE, LYSAKER, AND ROBINSON

minority but not inconsequential number of respondents reported • Luckily, a number of effective interventions are available for
beliefs that doctors understand the chemical bases of depression treating depression. Such interventions include a variety of phar-
and use objective chemical measures to quantify depression and macological as well as nonpharmacological approaches, some-
guide its treatment. To the extent that such beliefs are inaccurate, times used alone and sometimes in combination with one another.
they may limit one’s understanding of treatment options and/or
leave one with overly high expectations of treatment success. Before closing, we wish to reiterate that our survey data were
Interesting clinical questions are raised to the extent that the derived from a convenience sample and as such cannot be confi-
beliefs of your depressed clients mirror those of some in our dently generalized to U.S. adults as a whole. Limitations of our
sample. For example, how much information should be provided survey also included potential item wording and self-selection
to clients concerning the validity (or potential lack thereof) of biases and a primary reliance on response types (i.e., Likert and
chemical imbalance explanations for depression? Is it unethical to categorical responses), which resulted in data that are perhaps
gloss over the complexities of this and related (e.g., antidepressant somewhat artificial. We recommend future studies in this area
vs. placebo efficacy) issues? What about the client who has been attempt to avoid such limitations. Future studies could also be
referred for adjunctive psychotherapy but does not see such treat- expanded to include questions such as these: How do some lay-
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persons come to believe that biochemical measures of depression

This document is copyrighted by the American Psychological Association or one of its allied publishers.

ment as important because she or he expects medication to resolve

her or his depression? Alternately, how should you approach a are widely used? Does personal endorsement of the chemical
discouraged patient who had assumed that his or her chemical imbalance explanation affect how one responds to others who
imbalance would respond (but has not responded) to the antide- come to them for advice regarding depression treatment? How
pressant seen on television? does one’s explanatory style for negative events influence etiolog-
The beliefs of other professionals and stakeholders concerning ical beliefs concerning depression? Are persons who endorse the
chemical imbalance explanations also have the potential to impact imbalance explanation for depression more likely to offer social
your practice of psychology. For example, if you work as part of support to depressed persons? What beliefs do different profes-
a team involving medical staff, will views diverging from a chem- sionals (e.g., nurses vs. counselors) hold concerning imbalance
ical imbalance model of depression clash with those adhering to a theories of depression? In closing, future studies might also ex-
purer medical model? If so, how might such differences affect a amine changes over time, both in and outside the United States, of
particular client’s treatment, your relationship with that client, lay endorsement of chemical imbalance explanations.
your relationships with coworkers, and even potential referrals?
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