Journal of Psychiatric Research 37 (2003) 325–333

www.elsevier.com/locate/jpsychires

Clinician recognition of anxiety disorders in depressed outpatients

Mark Zimmerman*, Iwona Chelminski
Department of Psychiatry and Human Behavior, Brown University School of Medicine, Rhode Island Hospital, Providence, RI 02905, USA

Received 5 September 2002; received in revised form 7 January 2003; accepted 23 January 2003

Abstract
The recognition of anxiety disorders in depressed patients has potential clinical significance because their presence predicts
poorer outcome and may influence treatment selection. In routine clinical settings, an unstructured diagnostic interview is
typically used to assess patients at the initiation of treatment. Unstructured interviews, however, may result in missed diag-
noses, with potential negative clinical consequences. The goals of the present study were to examine whether anxiety disorders
are less frequently identified using a routine unstructured clinical evaluation than a semi-structured diagnostic interview in
patients with a principal diagnosis of major depressive disorder (MDD), and to determine patients’ desire for treatment for
comorbid anxiety disorders. Psychiatric outpatients with MDD were evaluated with either a semi-structured or an unstructured
diagnostic interview. Current DSM-IV anxiety disorder diagnoses were compared in the two, nonoverlapping, groups of depressed
psychiatric outpatients seen in the same practice setting. Patients with comorbid anxiety disorders who were interviewed with
the semi-structured interview were asked if they wanted treatment to address their anxiety symptoms. Individuals interviewed
with the semi-structured interview were diagnosed with significantly more current anxiety disorders than individuals who were
assessed with an unstructured interview. There was variability in patients’ desire for treatment of the different anxiety dis-
orders, though for each disorder the majority of patients wanted treatment to address the anxiety symptoms. In psychiatric
outpatients with a principal diagnosis of MDD psychiatrists underrecognize anxiety disorder comorbidity for which patients want
treatment.
# 2003 Elsevier Science Ltd. All rights reserved.
Keywords: Anxiety disorders; Depression; Comorbidity; Semi-structured interview; Desire for treatment

1. Introduction Methods to Improve Diagnostic Assessment and Ser-

vices (MIDAS) project, we found much lower comor-
Anxiety is frequent in depressed patients, though bidity rates in psychiatric outpatients diagnosed
most studies of this relationship have been of symptoms according to unstructured clinical interviews than a
of anxiety rather than diagnosable anxiety disorders standardized research interview (Zimmerman and Mat-
(Clayton et al., 1991; Joffe et al., 1993; Van Valkenburg tia, 1999). Shear and colleagues in Pittsburgh (Shear et
et al., 1984). Five studies of the full range of DSM- al., 2000) and Basco and colleagues in Texas (Basco et
defined anxiety disorders in depressed psychiatric out- al., 2000) reported similar results.
patients each found that when diagnoses are based on Previously we examined diagnostic underdetection in
semi-structured diagnostic interviews more than 40% of a broad cross-section of psychiatric outpatients by
the patients had a comorbid anxiety disorder (Fava et comparing diagnostic frequencies in two separate
al., 2000; Melartin et al., 2002; Pini et al., 1997; San- cohorts of patients, one evaluated with an unstructured
derson et al., 1990; Zimmerman et al., 2000). clinical interview and the other evaluated with a semi-
During the last 2 years three reports have questioned structured research diagnostic interview (Zimmerman
the adequacy of the unstructured clinical diagnostic and Mattia, 1999). In the present report we narrow our
interview. In an earlier report from the Rhode Island focus to the detection of anxiety disorders in depressed
patients because of the high frequency of this comor-
* Corresponding author. Tel.: +1-401-277-0724; fax: +1-401-277-
bidity, and the potential impact this comorbidity might
0726. have on treatment planning. As an indicator of the
E-mail address: mzimmerman@lifespan.org (M. Zimmerman). potential importance of anxiety disorder comorbidity
0022-3956/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0022-3956(03)00020-7
326 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333

on treatment planning with depressed patients we asked patients’ responses on the questionnaire. The institu-
patients whether they were interested in having treat- tional review board reviewed and approved the eval-
ment directed towards the comorbid anxiety disorder. uation protocol, and all participants provided written
Thus, in the present report from the Rhode Island informed consent.
MIDAS project we examined the following three ques- All patients were presenting for their initial diagnostic
tions: (1) In psychiatric outpatients diagnosed with evaluation in a community based, hospital affiliated,
major depressive disorder (MDD), how well do psy- outpatient psychiatric practice. For convenience, we
chiatrists do in detecting the presence of comorbid refer to the patients interviewed with the SCID (which
anxiety disorders? (2) Are there differences between the was followed by an unstructured interview by their
anxiety disorders regarding patients’ desire for treat- treating psychiatrist) as the SCID sample, and the
ment? (3) Do psychiatrists underrecognize anxiety dis- patients interviewed only with the psychiatrist’s
order comorbidity for which patients want treatment? unstructured clinical interview as the nonSCID sample.
In the non SCID sample, unstructured diagnostic eval-
uations were conducted by board certified or board eli-
2. Methods gible attending psychiatrists. Diagnoses were based on
DSM-IV criteria. Clinicians completed a standardized
More than two thousand patients were evaluated intake form modeled on the Intake Evaluation Form of
upon presentation for outpatient treatment to the Mezzich and colleagues (1981). The intake form inclu-
Rhode Island Hospital Department of Psychiatry out- ded space for a narrative description of the chief com-
patient practice. This private practice group pre- plaint, history of present illness, and past psychiatric
dominantly treats individuals with medical insurance history. In addition, there was a checklist to record the
(including Medicare but not Medicaid) on a fee-for-ser- presence or absence of substance use problems, a his-
vice basis, and it is distinct from the hospital’s out- tory of sexual or physical abuse, psychotic symptoms,
patient residency training clinic that predominantly panic attacks, phobias, obsessions, compulsive beha-
serves lower income, uninsured, and medical assistance vior, and all of the symptoms of major depression. On
patients. the last page of the five-page form clinicians recorded
We examined psychiatric diagnoses made during the patients’ DSM-IV multiaxial diagnoses. Research assis-
initial intake evaluation in two nonoverlapping cohorts tants recorded the results of the clinician’s diagnostic
of patients—in one group patients were interviewed by evaluation written on the last page of the intake form,
attending psychiatrists with an unstructured clinical and collected demographic information from the narra-
interview (n=1352), and in the other group patients tive. When estimating disorder prevalence rates for
interviewed with the Structured Clinical Interview for clinical diagnoses, we included as cases patients whom
DSM-IV (n=800). The diagnostic procedures employed the clinicians diagnosed with a ‘‘ruleout’’ disorder.
in each group are described further below. Not all When patients called to schedule their initial
patients were interviewed with the SCID because of the appointment they were offered the opportunity to
lack of availability of diagnostic raters and patients’ receive a more comprehensive evaluation than the usual
preference for the briefer unstructured evaluation. It unstructured clinical evaluation. The patients were told
should be noted that in our earlier report comparing the that they would be interviewed by two people—first by
diagnostic practices of clinicians and researchers the a diagnostic rater who would conduct a comprehensive
samples were ascertained sequentially (Zimmerman and evaluation, and then by a psychiatrist. After the SCID,
Mattia, 1999). That is, 500 patients were evaluated by the rater presented the case to a psychiatrist who
clinicians, and subsequent to this 500 patients were reviewed the findings of the evaluation with the patient.
interviewed with the SCID. That was not the case in the If the psychiatrist obtained additional information to
present study in which the two groups of patients were modify the diagnosis this was discussed with the SCID
ascertained during the same time period, though group rater. Although not systematically recorded, it was rare
assignment was not based on random assignment. The for a diagnosis to be added after the psychiatrist’s
patients in our prior report are not included in the pre- review of the case.
sent analyses. The core of the diagnostic evaluation was the January
Before the initial evaluation all patients completed the 1995 DSM-IV patient version of the SCID (First et al.,
Psychiatric Diagnostic Screening Questionnaire (PDSQ, 1995). During the course of the study, joint-interview
Zimmerman and Mattia, 2001a,b) as part of their initial diagnostic reliability information has been collected on
paperwork. The PDSQ is a broad-based screening 47 patients. For mood and anxiety disorders the Kappa
questionnaire assessing the symptoms of DSM-IV coefficients were: MDD (k=0.91), dysthymic disorder
mood, eating, anxiety, substance use, and somatoform (k=0.88), bipolar disorder (k=0.85), panic disorder
disorders. Because the validity of the PDSQ was under (k=1.0), social phobia (k=0.84), obsessive-compulsive
investigation, the clinicians were kept blind to the disorder (OCD; k=1.0), specific phobia (k=0.91), gen-
 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333 327

eralized anxiety disorder (GAD; k=0.93), and post- clinical patient samples were clinically similar as asses-
traumatic stress disorder (PTSD; k=0.91). Details sed by a self-report measure of DSM-IV symptoms.
regarding interviewer training and supervision are avail-
able in other reports from the MIDAS project (Zimmer- 3.2. Anxiety disorder comorbidity rates in depressed
man and Mattia, 1999, 2001a,b; Zimmerman et al., 2000). outpatients diagnosed clinically or by a semistructured
Two questions about reasons for seeking treatment diagnostic interview
were asked: ‘‘Was (symptoms of disorder) one of the
main reasons you decided to seek treatment now?’’ If More current anxiety disorders were diagnosed in the
the patient responded ‘‘no’’ to this question, they were SCID than the nonSCID sample (1.0  1.1 vs. 0.3  0.6,
asked: ‘‘Now that we’ve talked about (symptoms of t=10.4, P < 0.001). The data in Table 2 shows that each
disorder), would you like your treatment here to address anxiety disorder except PTSD was significantly more
these symptoms?’’ When asking these questions the frequently diagnosed in the SCID sample. Social phobia
interviewer reviewed the features of the disorder that and specific phobia were more than 15 times more fre-
had just been described so the patient understood to quently diagnosed in the SCID sample.
what the question referred. To determine whether the difference in diagnostic
In our analyses, first we compared the frequency of frequencies between the SCID and clinical interview was
current DSM-IV anxiety disorders in the SCID and a general phenomenon or specific to anxiety disorders
nonSCID samples. Then, we determined the percentage we compared the two groups on the second most fre-
of patients in the SCID sample who indicated that they quently diagnosed class of disorders—substance use
wanted treatment for each of the comorbid diagnoses. disorders. There was no difference between SCID and
Finally, we recomputed the prevalence of anxiety dis- clinically diagnosed patients in rates of current alcohol
orders in the SCID sample by requiring both disorder abuse/dependence [6.0% vs. 4.9%, w2=0.5, n.s.;
presence and desire for treatment, and compared this to OR=1.2 (95% C.I. 0.7–2.2)] or drug abuse/dependence
the prevalence rate in the nonSCID sample. This [4.7% vs. 3.4%, w2=0.8, n.s.; OR=1.4 (95% C.I. 0.7–
addresses the question of whether psychiatrists under- 2.7)].
recognize anxiety disorder comorbidity for which The effect of demographic factors on anxiety disorder
patients want treatment. t-Tests were used to compare comorbidity detection was determined by examining the
the samples on continuously distributed variables. study group by demographic variable interaction term
Categorical variables were compared by the chi-square in an analysis of variance model that included sex, edu-
statistic, or by Fisher’s Exact test if the expected value cation, marital status, age, and assessment method as
in any cell of a 22 table was less than 5. The degree of variables. None of the interaction terms was significant.
inequality between the rates of diagnoses in the two The mean number of anxiety disorder diagnoses was
samples was tested using odds ratios (OR) calculated higher in the SCID than the nonSCID samples for
with 95% confidence intervals (CI). women (1.1  1.1 vs. 0.3  0.5, t=9.36, P < 0.001) and
men (0.9  1.1 vs. 0.3  0.6, t=4.79, P < 0.001), currently
married (0.9  1.1 vs. 0.3  0.6, t=5.59, P < 0.001) and
3. Results not married patients (1.1  1.1 vs. 0.3  0.6, t=8.75,
P < 0.001), patients above and below the median age of
3.1. Comparability of the samples 39 years (age 539: 0.9 1.1 vs. 0.3 0.5, t=6.55,
P< 0.001; age 438: 1.1 1.2 vs. 0.3 0.6, t=8.14,
A principal diagnosis of current nonbipolar MDD P< 0.001), and patients who did or did not go beyond a
was given to 610 patients in the nonSCID sample and high school education (some college: 0.9 1.1 vs. 0.3 0.5,
300 patients in the SCID sample. Patients diagnosed t=8.48, P< 0.001; high school graduate or less: 1.2 1.1
with bipolar depression are not included in this report. vs. 0.3 0.6, t=6.60, P< 0.001).
The depressed patients in the nonSCID sample were
significantly older than the depressed patients in the 3.3. Patients desire for treatment of their comorbid
SCID sample (Table 1). In addition, patients in the anxiety disorders
nonSCID sample were significantly less likely to have
attended some college and to be white. There was no Table 3 shows that the depressed patients evaluated
difference in gender or marital status. with the SCID most often wanted treatment of their
Patients in the clinical and SCID samples were com- symptoms of GAD, panic disorder, and PTSD. One-
pared on the PDSQ self-report symptom scale, control- half to two-thirds of patients wanted treatment of social
ling for age. There were no significant differences phobia, OCD, and specific phobia. Overall, 86% of the
between the groups on each of the 13 PDSQ subscale depressed patients with at least one anxiety disorder
scores. Thus, despite significant, albeit modest, differ- wanted their treatment to address a comorbid anxiety
ences in demographic characteristics, the SCID and disorder.
328 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333

Table 1
Demographic characteristics of patients with a principal diagnosis of DSM-IV major depressive disorder in clinical and SCID samples

Clinical (n=610) SCID (n=300) w2 P

N % N %

Female gender 424 69.6 203 67.7 0.4 n.s.

Caucasian 484 79.3 264 88.0 10.3 <0.01

Education 10.9 <0.05

Less than 12th grade 84 14.0 27 9.0
HS graduation or equivalency 170 28.2 74 24.7
Some college 190 31.6 125 41.6
Four year college or more 158 26.2 74 24.7

Marital status 10.7 n.s.

Married 254 42.8 122 40.7
Living together 35 5.9 17 5.7
Widowed 24 4.0 4 1.3
Separated 48 8.1 20 6.7
Divorced 108 18.2 51 17.0
Never married 124 20.9 86 28.7

Mean S.D. Mean S.D. t P

Age 40.8 14.3 38.8 11.8 2.3 P<0.05

Table 2
Frequency of current DSM-IV anxiety disorders in patients with a principal diagnosis of major depressive disorder in clinical and SCID samples

Anxiety disorders Clinical (n=610) SCID (n=300) OR 95% CI w2 P

N % N %

Panic disorder 49 8.1 47 15.7 2.1 1.4–3.2 12.4 <0.001

Specific phobia 5 0.8 37 12.3 17.0 6.6–43.8 60.6 <0.001
Social phobia 13 2.1 98 32.7 22.3 12.2–40.6 175.0 <0.001
Obsessive compulsive disorder 20 3.3 26 8.7 2.8 1.5–5.1 12.2 <0.001
Posttraumatic stress disorder 47 7.7 34 11.3 1.5 1.0–2.4 3.3 0.07
Generalized anxiety disorder 41 6.7 60 20.0 3.5 2.3–5.3 35.9 <0.001
Any anxiety disorder 144 23.6 172 57.3 4.3 3.2–5.8 100.9 <0.001

Table 3
Desire for treatment for current DSM-IV comorbid anxiety disorders in SCID patients with a principal diagnosis of major depressive disorder

Anxiety disorders Frequency of the disorder Desire for treatment

N N %

Panic disorder 47 46 97.9

Specific phobia 37 21 56.8
Social phobia 98 72 73.5
Obsessive compulsive disorder 26 21 80.8
Posttraumatic stress disorder 34 30 88.2
Generalized anxiety disorder 60 55 91.7
Any anxiety disorder 172 149 86.6

We re-computed the prevalence of anxiety disorders order. The data in Table 4 shows that the rate of each
in the SCID sample by raising the diagnostic thresh- anxiety disorder (except PTSD) remained significantly
old by requiring both the presence of the disorder as higher in the SCID sample than in the nonSCID
well as the patients’ desire for treatment of the dis- sample.
 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333 329

Table 4
Frequency of current DSM-IV anxiety disorders in patients with a principal diagnosis of major depressive disorder in clinical and SCID samples

Anxiety disorders Clinical (n=610) SCID (n=300)+ desire for treatmenta w2 P

N % N %

Panic disorder 49 8.1 46 15.3 11.5 <0.001

Specific phobia 5 0.8 21 7.0 27.7 <0.001
Social phobia 13 2.1 72 24.0 113.6 <0.001
Obsessive compulsive disorder 20 3.3 21 7.0 6.5 <0.05
Posttraumatic stress disorder 47 7.7 30 10.0 1.4 n.s.
Generalized anxiety disorder 41 6.7 55 18.3 28.7 <0.001
Any anxiety disorder 144 23.6 149 49.7 62.6 <0.001
a
Indicates patients with the disorder who wanted treatment for it.

4. Discussion tice are poor diagnosticians who failed to detect

comorbidity. While it is not possible to rule out this
Our results suggest that in psychiatric outpatients possibility, elswhere we reported that the likelihood of
with a principal diagnosis of MDD psychiatrists under- detecting a comorbid disorder by the clinicians in our
recognize anxiety disorder comorbidity, and when an practice is higher than the rates found in other reports
anxiety disorder is present patients usually want their of comorbidity based on clinical evaluations (Zimmerman
treatment to address the comorbid anxiety disorders. and Mattia, 1999). Moreover, our findings are con-
There are several alternative explanations for the lower sistent with those of other studies comparing unstruc-
rate of anxiety disorders in the nonSCID than the SCID tured clinical evaluations with the results of semi-
sample. First, it is possible that the difference in structured diagnostic interviews (Basco et al., 2000;
comorbidity rates reflects true sample differences, and Shear et al., 2000). Thus, it does not appear that the
the nonSCID sample was a less severely ill group. This psychiatrists in this study were more likely than other
is, however, extremely unlikely because patients in the psychiatrists to underrecognize diagnostic comorbidity.
two samples scored similarly on the PDSQ anxiety dis- Fourth, perhaps the problem is not with clinician
order subscales. This makes it less likely that the diag- underdiagnosis but with semi-structured research inter-
nostic differences between the samples reflect a real view overdiagnosis. Interviews such as the SCID are
inter-sample difference in level of pathology. Sig- viewed as diagnostic ‘‘gold standards,’’ but it is possible
nificantly more patients in the nonSCID than the SCID that they are too sensitive and result in false positive
sample received a principal diagnosis of MDD, though diagnoses. Or perhaps we were biased to overdiagnose
the two groups scored similarly on the PDSQ depres- on the SCID. Inconsistent with this is the comparability
sion subscale. Because nondepressive disorders were of the anxiety disorder rates in our study with those of
more frequently diagnosed when the SCID was used, it other studies that used research diagnostic interviews
is likely that some of the SCID patients received a for assessing anxiety disorders in depressed patients
principal diagnosis of a nondepressive disorder with (Fava et al., 2000; Melartin et al., 2002; Pini et al., 1997;
comorbid MDD, and this accounts for the difference Sanderson et al., 1990). Also inconsistent with the
between groups in diagnosing principal MDD. SCID-overdiagnosis hypothesis is that when the results
Second, it is possible that the lower anxiety disorder of the SCID evaluations were presented to the clin-
rates in the nonSCID sample are the result of clinicians’ icians, the clinicians made more diagnoses in the
deliberate underdocumentation of psychopathology. If patients’ clinical charts (data available upon request).
clinicians censor from their records diagnostic informa- Because clinicians confirmed the SCID diagnoses, and
tion that patients are most embarrassed, ashamed, or recorded more diagnoses in their patients’ charts com-
stigmatized by, then it would be inappropriate to con- pared to when they conducted unstructured clinical
clude that comorbidity was not being detected. How- evaluations, it is less likely that diagnostic bias accounts
ever, post hoc conversations with the clinicians in the for our findings.
practice indicated that they did not deliberately omit
diagnostic information from the patients’ charts. In 4.1. Implications of anxiety disorders in depressed
addition, the drug and alcohol use disorders were diag- patients
nosed with equal frequency in the SCID and nonSCID
samples. This, too, is inconsistent with the censoring The recognition of comorbidity is not simply of
hypothesis. academic interest—it has important clinical signi-
Third, underdiagnosis may be a local rather than a ficance. Epidemiological studies such as the National
widespread problem. Perhaps the clinicians in our prac- Comorbidity Study have demonstrated that depressed
330 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333

individuals with a history of anxiety disorders are at of a comorbid anxiety disorder (Fava et al., 2000).
increased risk for hospitalization, suicide attempt, and However, at least three controlled studies of the prog-
greater impairment from the depression (Kessler et al., nostic significance of anxiety disorders in depressed
1994, 1996). The co-occurrence of anxiety disorders in patients have been conducted.
depressed patients has been associated with a more Fava and colleagues (Fava et al., 1997) treated nearly
chronic course of depression in psychiatric patients, 300 depressed outpatients with fluoxetine and found
primary care patients, and epidemiological samples. that patients with a comorbid anxiety disorder were less
Van Valkenberg et al. (1984) reported that depressed likely to respond than depressed patients without a
patients with anxiety neurosis (diagnosed according to comorbid anxiety disorder. In Brown, Schulberg and
the Washington University criteria) had poorer out- colleagues’ (1996) primary care study of nortriptyline
come and greater psychosocial impairment than and interpersonal therapy, the presence of a comorbid
depressed patients without an anxiety disorder. In the anxiety disorder was associated with a nonsignificantly
NIMH Collaborative Depression Study, the presence of higher rate of premature discontinuation from treat-
panic attacks predicted a lower recovery during the first ment, and patients with a lifetime history of panic dis-
2 years of the follow-up interval (Coryell et al., 1988). order had a lower recovery rate than patients without
Grunhaus and colleagues (Grunhaus, 1988) similarly panic. Levitt et al., (1993) treated 31 depressed out-
found poorer outcome in depressed patients with patients with seasonal affective disorder (SAD) with
comorbid panic disorder than depressed patients with- light therapy and 25 patients without SAD with desi-
out panic. In an 8-month follow-up of depressed pri- pramine or imipramine. The presence of a comorbid
mary care patients treated with nortriptyline or anxiety disorder did not predict response to light ther-
interpersonal therapy, patients with a history of GAD apy in the patients with SAD. In the patients without
or panic disorder were less likely to have recovered from SAD who were treated with a TCA, the presence of a
their depressive episode (Brown et al., 2000). In the comorbid anxiety disorder was associated with a sig-
Medical Outcomes Study, panic or phobic disorder, but nificantly lower response rate. None of these studies
not GAD, coexisting with MDD predicted a lower included a placebo group.
remission rate 1 year after the initial evaluation, though The poorer outcome of anxious depressed patients
2 years after the evaluation only panic disorder was compared to nonanxious depressed patients, particu-
significantly associated with a lower remission rate larly in naturalistic longitudinal studies of the course of
(Sherbourne and Wells, 1997). Gaynes and colleagues depression, raises the question of whether improving the
(Gaynes et al., 1999) prospectively followed 68 primary detection of anxiety disorders would result in improved
care patients with MDD every 3 months for 1 year after outcome. The clinical implications of underdiagnosing
the initial diagnostic evaluation. Half of the patients anxiety disorders in depressed patients depend on two
had a coexisting anxiety disorder, the most frequent factors—(1) whether or not anxiety disorders have an
being social phobia. Twelve months after intake the impact on the longitudinal course of depression, and (2)
patients with a comorbid anxiety disorder were sig- the availability of effective treatment that is specific for
nificantly more likely to still be in an episode of depres- anxiety disorders. As reviewed above, the literature
sion, and they experienced more disability days during suggests that the presence of a comorbid anxiety dis-
the course of the 12 months than the depressed patients order is associated with a poorer outcome. The second
without an anxiety disorder. question is whether or not appropriate intervention will
There are few controlled treatment studies of the improve outcome. It is logical to speculate that
prognostic or treatment implications of anxiety dis- improved diagnostic practice, resulting in improved
orders in depressed patients because many of these detection of anxiety disorders and treatment directed to
studies exclude patients with clinically significant the additional concerns related to anxiety disorders, will
comorbid anxiety disorders (Bennie et al., 1995; New- result in improved treatment outcome. However, it is
house et al., 2000; Rapaport et al., 1996; Tollefson et al., also possible that the presence of a comorbid anxiety
1994a). We are not aware of any effectiveness studies, in disorder will be associated with poorer outcome even
which exclusion criteria are minimal, that have exam- when the diagnosis is known. In studies finding that the
ined the prognostic significance of comorbid anxiety presence of a comorbid anxiety disorder was associated
disorders. Nor are there studies of the influence of with a greater likelihood of depression chronicity, it is
comorbid anxiety disorders on treatment selection for not clear whether the health care providers were aware
patients seen in routine clinical practice. While there are of the researchers’ anxiety disorder diagnoses. It is
several controlled studies of the prognostic significance therefore unknown if the greater chronicity of depres-
of anxious features in depressed patients (Joffe et al., sion in patients with high anxiety was due to the failure
1993; Tollefson et al., 1994b), we do not consider these of appropriate treatment or the failure to provide
studies here because of the uncertain relationship appropriate treatment. There are no studies that have
between the severity of anxiety features and a diagnosis examined the important question of whether the treat-
 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333 331

ment of depressed patients with and without comorbid clinical populations using unstructured clinical inter-
anxiety disorders should differ; though clinical experi- views. Given that the structured interview is considered
ence and inference from the extant literature suggests the diagnostic gold standard, this suggests that comor-
that the presence of a comorbid anxiety disorder bidity is underdiagnosed in routine clinical settings.
impacts upon case formulation and treatment planning. Structured interviews such as the SCID are too long
and unwieldy for use in routine outpatient mental
4.2. Treatment planning in depressed patients with health settings. A less time consuming semi-structured
comorbid anxiety disorders interview, such as the Mini International Neu-
ropsychiatric Interview (MINI, Sheehan et al., 1998) is
Experts in the treatment of depression with comorbid brief enough to be incorporated into clinical practice;
anxiety disorders have described how knowledge of a however, this would require a significant change in how
comorbid anxiety disorder might impact upon the clinicians conduct their diagnostic evaluations. It is
treatment of MDD (Nutt, 1999; Pollack and Marzol, likely that clinicians already in practice will resist such a
2000; Roy-Byrne, 1999). For example, treatment plan- change. The difficulty of convincing clinicians to use a
ning for depressed patients with a comorbid anxiety brief semi-structured interview in clinical practice, even
disorder could include referral for CBT for the anxiety when underrecognition of psychopathology has been
disorder. Choice and dosing of pharmacologic agents well established, was reported by Spitzer and colleagues
might also vary. Depressed patients with a comorbid (1999) in their research on the PRIME-MD in primary
panic disorder might have a benzodiazepine prescribed care settings. It is well known that changing physician
as well as an antidepressant at treatment onset in order behavior is difficult, and we believe that there will be
to achieve more rapid relief from the panic attacks. If an significant obstacles to overcome in getting clinicians to
SSRI is prescribed, dosage titration might be more gra- routinely use a measure such as the MINI. It is more
dual (Gorman et al., 1987). The best empirically sup- likely that clinicians would use an inexpensive, screening
ported treatment decision is the preferential selection of instrument that does not intrude on the clinician’s usual
an SSRI over a TCA in the treatment of depressed practice but provides clinically relevant diagnostic
patients with comorbid OCD (Hoehn-Saric et al., 2000). information. Potentially, a reliable and valid self-report
Depression comorbid with social phobia might also be screening questionnaire would enhance and not inter-
preferentially prescribed an SSRI. The addition of a fere with usual clinical practice. Elsewhere we described
benzodiazepine might be considered in depressed the reliability and validity of a broad-based screening
patients with comorbid GAD. questionnaire for Axis I disorders (Zimmerman and
In the recently revised APA Practice Guideline for the Mattia, 2001a,b), and in a separate report we examine the
treatment of MDD (2000), four suggestions were made ability of the scale to detect comorbid anxiety disorders
regarding the treatment of depression comorbid with an in patients with a principal diagnosis of MDD (sub-
anxiety disorder: initiate antidepressant medication at mitted for publication). The completion of paperwork
lower than usual dosages and slowly titrate upwards; before an initial evaluation is common in physicians’
SSRIs and clomipramine are effective for OCD and offices. The advantage of the empirically developed
therefore should be considered when treating depressed measures such as the PDSQ over home-grown forms is
patients with comorbid obsessive features; buproprion that the psychometric and diagnostic properties of the
has not been found to be effective in the treatment of scientifically studied instruments have been established
panic disorder (and although the guidelines do not spe- thereby guiding the interpretation of the results.
cifically state this, the inference is that this medication Finally, our review of the treatment literature indi-
should not be considered a first line treatment for cates that there are few placebo-controlled studies that
depressed patients with this comorbidity); and benzo- have examined the effectiveness of treatments for
diazepines may be beneficial augmenting agents in the patients with comorbid depression and anxiety dis-
short term. Except for the single OCD study, none on orders. Because of the high frequency of this comorbid-
the treatment suggestions described above have been ity, this area of treatment research warrants further
subjected to empirical testing. study. Also sparse are studies examining differences
between active treatment and placebo in patients with
4.3. Future directions and without an anxiety disorder. For example, Smith,
Londborg and colleagues recently found that depressed
The literature is consistent concerning the prevalence patients treated with fluoxetine and clonazepam
and impact of anxiety disorder comorbidity in depressed responded more rapidly than patients treated with
patients. Substantial rates of comorbid disorders have fluoxetine plus placebo (Londborg et al., 2000; Smith et
been found in epidemiological and clinical populations al., 1998). Unfortunately, they did not examine whether
using structured research diagnostic interviews. How- this difference was true of patients with and without an
ever, much lower comorbidity rates have been found in anxiety disorder. Future treatment studies should
332 M. Zimmerman, I. Chelminski / Journal of Psychiatric Research 37 (2003) 325–333

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