____________________________________________________________________________________________________
Subject PSYCHOLOGY
Paper No and Title PAPER No.15: Clinical Psychology
Module No and MODULE No.20: Delusional Disorder
Title
Module Tag PSY_P15_M20
TABLE OF CONTENTS
1. Learning Outcomes
2. Introduction to delusional disorder
3. Problems in defining Delusional Disorder
4. Symptoms
5. Prognosis/ course
6. Diagnosis
6.1 Changes in DSM-V
6.2 classification of delusional disorder
7. Etiological approaches to delusional disorder
7.1 Biological perspective
7.2 Psychological approach
8. Epidemiology
8.1 Prevalence rates
8.2 Age of onset
8.3 Sex differences
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
8.4 Other demographic factors
8. Treatment
9.1 Pharmacological treatment
9.2 Psychological treatment
10. Summary
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
1. Learning Outcomes
After studying this module, you shall be able to
Know what are Delusional Disorders and how they are different from schizophrenia, mood
disorders etc
Learn about the symptomatology of delusional disorder
Identify the diagnostic methods and criteria
Evaluate the various treatment approaches
2. Introduction
Delusional Disorder was initially known as “Paranoia”. Over the years, the concept of paranoia has
undergone many changes. As per Kraepelin’s concept for example, paranoia was considered different
from schizophrenia (dementia praecox) characterized by absence of disturbance in thought, defect only in
judgment and no change in personality as in the latter. Some like Henderson and Gillespie (1994)
considered Paranoia as part of the Paranoid spectrum that had paranoia and paranoid schizophrenia at the
extremes with an intermediate Paraphrenia. In 1977 George Winokur renamed Paranoia as Delusional
Disorder . Delusions are defined in the 4th edition of the Diagnostic and Statistical Manual of Mental
Disorders (DSM-IV) of the American Psychiatric Association (1994) as follows:
“Delusion” is basically a false personal belief based on incorrect inference about external reality and
firmly sustained in spite of what almost everyone else believes and in spite of what constitutes
incontrovertible and obvious proof or evidence to the contrary. The belief is not one ordinarily accepted
by other members of the person’s culture or subculture (i.e., it is not an article of religious faith). When a
false belief involves an extreme value judgment, it is regarded as a delusion only when the judgment is so
extreme as to defy credibility.”
Delusional Disorder is thus a rare mental illness, involving delusions, which are mostly non-bizarre and
involve situations that may occur in real life. People with Delusional Disorders do not necessarily face a
lot of maladjustment, while some may be so preoccupied with their delusions that they may face
considerable distress.
3. Problems in defining Delusional Disorder
There was a lot of confusion about categorising delusional disorder as a distinct disorder.The first
problem that is faced while defining delusional disorder is the very definition of delusion. The criteria by
which delusions are operationally defined have been debated upon which basically focus on the
ambiguity of concepts of “truth” and “false” and the steps used to establish the nature of the statements.
Due to this, many alternative definitions of Delusions have emerged:
Oltmann (1988) used descriptive dimensions and provided a list of characteristics to define delusions
which can be briefly put as – “A belief which seems incredible to other people and is not shared by
anybody else, held with firm conviction regardless of presence of contradictory evidence, leads to
emotional preoccupation, is concerned solely with the individual, leads to subjective distress in
occupational and social functioning and no efforts are made by the person to resist this belief.”
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
Heidelber School: Karl Jaspers- the founder of this school
based in the University of Heidelberg – introduced three criteria
for the definition of delusions- (1) Subjective certainty, (2) incorrigibility, and (3) the realistic
impossibility of the content.
Thus, several definitions of both delusions and delusional disorder exists which lack consensus. This may
probably be due to the infrequency of the disorder and due to the fact that patients generally don’t
actually seek treatment and continue living with the beliefs. It is easily misdiagnosed as delusions form an
important part of the symptomatology of various other conditions like Schizophrenia, Mood-affective
disorders, Drug-abuse etc.
4. Symptoms of Delusional Disorders
The basic underlying feature of the clinical picture of delusional disorder is clearly the delusional system
of thoughts and beliefs which are rigidly held on to in spite of contradictory evidence. These are stubborn
and mostly false beliefs that are extremely difficult to change or modify. A unique feature is that the facts
may be interpreted and reinterpreted to prove and fit to the delusional belief instead of the other way
around. Thus, there is a problem in interpretation of facts. Since these delusions are mostly non-bizarre in
nature hence do not lead to major impairment except personal distress, unless the event directly involves
the delusional beliefs.
The delusions in delusional disorder have mostly of two basic properties i.e., these are Systematized and
Encapsulated and in varying degrees. Systematisation refers to the branching out or network of the set of
delusional beliefs gather around a common theme. Encapsulation refers to the phenomena of the thoughts
outside the realm of the delusional system being unaffected. So other cognitive abilities stay intact and
functional because of which there is very little functional impairment.
Manschreck (2000) talked about subjective and objective features of delusional disorder which are:
Subjective features: delusions of persecution, reference, grandeur, infidelity, supernatural, love,
jealousy and imposture.
Objective features include sensitivity, suspiciousness, moodiness, self-righteousness, irritability,
hate, litigiousness, aggressiveness, obstinacy etc.
All these features are quite difficult to define operationally thus making the judgement of the features
depends on merely the extremeness or deviances in the behaviours.
Munro (1992) also provided many clinical features of delusional disorder. He contrasted the features of
Delusional and normal modes of thought and behaviour. In the former, the person is preoccupied with
delusional ideas, is over alert and overdriven, experiences distress whereas in normal mode the person is
in a relatively calm mood, displays reasonable emotions, and is able to engage is everyday topics.
Other symptoms may include various types of hallucinations- usually tactile and olfactory are more
common and prominent. In delusional disorder there may be certain types of hallucinations but unlike
schizophrenia, there is no impairment in form of thinking.
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
5. Course/ prognosis
The course of the disorder is varied. Typically, the course is chronic with high persistence of delusions.
Studies are not very consistent and there are people who suffer severe impairment while others who show
a high level of recovery. There are moderate chances of relapses within few months or years. This is
mostly because of reluctance to adhere to treatment or medication which can lead to worse prognosis.
People with the disorder generally retain normalcy in many areas of functioning and can do reasonably
well with little or no assistance.
6. Diagnosis
The criteria for Delusional Disorder as per DSM-IV are as follows:
A. The essential feature of Delusional Disorder is the presence of one or more nonbizarre delusions that
persist for at least 1 month.
B. A diagnosis of Delusional Disorder is not given if the individual has ever had a symptom presentation
that met Criterion A for Schizophrenia
C. Auditory or visual hallucinations, if present, are not prominent. Tactile or olfactory delusions may be
present (and prominent) if they are related to the delusional theme.… Apart from the direct impact of the
delusions, psychosocial functioning is not impaired, and behaviour is not markedly delusional Disorder or
bizarre.
D. If mood episodes occur concurrently with the delusions, the total duration of these mood episodes is
relatively brief compared to the total duration of the delusional period.
E. The delusions are not due to the direct physiological effects of a substance (e.g., cocaine) or a general
medical condition (e.g., Alzheimer’s disease, systemic lupus erythematous)
6.1 Changes in DSM- V
There are a few changes given in DSM-V in the description and diagnostic criteria of delusional disorder
as it was given in DSM-IV. “Criterion A for Delusional Disorder no longer has the requirement that the
delusions must be non-bizarre. A specifier for bizarre type delusions provides continuity with DSM-IV.
The demarcation of Delusional Disorder from psychotic variants of obsessive-compulsive disorder and
body dysmorphic disorder is explicitly noted with a new exclusion criterion, which states that the
symptoms must not be better explained by conditions such as obsessive-compulsive or body dysmorphic
disorder with absent insight/delusional beliefs. DSM-V no longer separates Delusional Disorder from
shared Delusional Disorder. If criteria are met for Delusional Disorder then that diagnosis is made. If the
diagnosis cannot be made but shared beliefs are present, then the diagnosis “other specified schizophrenia
spectrum and other psychotic disorder” is used.
The patients are also interviewed with the focus on obtaining valuable information about the person’s life
situation and past history. The psychologist/ psychiatrist may also obtain information by going through
past medical records, interviewing the patient’s family and other significant people in his/her
surroundings. The psychologist/ psychiatrist may use a semi-structured interview called a mental status
examination to assess the patient's concentration, memory and logical thinking. The mental status
examination is intended to reveal peculiar thought processes in the patient. The Peters Delusion Inventory
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
(PDI) is a psychological test that focuses on identifying and
understanding delusional thinking; but its use is more common in
research than in common practice.
6.2 Classification of delusional disorder
There are different types of Delusional Disorder based on the main theme of the delusions experienced.
The types of Delusional Disorder include:
Erotomanic: Someone with this type of Delusional Disorder has a strong belief that another
person, often someone important or famous, is in love with him or her and has erotic feelings
about the patient. The person might also attempt to contact the object of the delusion or stalk
them
Grandiose: A person with this type of Delusional Disorder has an inflated sense of self-worth,
power, knowledge, or identity. The person might believe he or she has some great talent, some
super-natural ability or has made an important discovery.
Jealousy: A person with this type of Delusional Disorder believes and accuses his or her sexual
partner with infidelity. Such patient generally believes that his/her partner has been cheating and
is in love with some other person.
Persecutory: People with this type of Delusional Disorder believe that they (or someone close to
them) are being mistreated, or that someone is spying on them or planning to harm them. They
believe that most or some set of people are always conspiring against them. It is not uncommon
for people with this type of Delusional Disorder to make repeated complaints to legal authorities.
Somatic: A person with this type of Delusional Disorder believes that he or she has a physical
defect or medical problem.
Mixed: People with this type of Delusional Disorder have two or more of the types of delusions
listed above.
Some other types of delusions include:
Controlled: in this type of delusion the person believes that his actions, thoughts and feelings etc
are all directed and controlled by some external force and not in his/her control.
Reference: Delusions of reference refers to the strongly held belief that random and everyday
events, objects, behaviours of others, etc. have a particular and unusual personal significance.
They may try and find some sort of secret message in these events just for themselves.
Delusion of poverty: in this the person strongly believes that he/ she is financially deprived and
impoverished.
Delusions of guilt: The belief that one is solely responsible for all the misery around him/her.
They assume blame of all the catastrophes and mishappenings around them or in places that are
not even remotely related to them. They think its because of their ill deeds that people in the
world are suffering.
Nihilistic Delusions: A belief that one is dead and doesn’t exist and everything around him is
unreal or the world is coming to an end etc.
Delusions of misidentification: one develops a strong belief that one’s identity, place etc has
changed.
Another broad classification of delusions is mood-congruent and mood-incongruent delusions. Whether
a delusion is mood- congruent or incongruent is decided by the relationship between the emotional or
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
affective state and the content of the delusion. For example if a
depressed person has delusion if guilt, worthlessness, nihilistic
delusion etc then it is mood congruent. Whereas if the person has delusions of grandiose accompanying
depression then they are mood incongruent delusions
6.2.1 Induced delusional disorder (folie a’ deux)
This is a rare condition where two family members or individuals, usually in a very close relationship and
are isolated from others by culture, language or physical proximity, (say belong to a particular family or
are a small group of immigrants) exhibit the same delusions where one partner induces the delusion in to
other one. The theme of the delusional system is often persecutory or grandiose. The person who
manifests the delusions first is called the primary case, which in turn influences the other person known
as the secondary case. The former shows true psychotic symptoms, whereas the latter would recover
promptly once he/ she is separated from the former. The delusional system may be part of Schizophrenia,
or it may be a primary delusional disorder in itself. Most often it occurs in family members who share
close genetic links. Otherwise, the causes are unknown and usually attributed to social isolation as well.
6.3 Differential Diagnosis
It is very important to rule out the possibilities of delusions originating from other medical problems.
Delusions occur in many other disorders- neurological and psychological thus increasing chances of
misdiagnosis. Delusions are manifested as one of the main symptoms in some neurological and medical
conditions like Parkinson’s disease, Huntington’s disease, Alzheimer’s disease, and Lymbic system
disorders like epilepsy, cerebrovascular diseases. Psychological disorders like schizophrenia, mood
disorders, obsessive-compulsive disorders, somatoform disorders and paranoid personality disorders are
also constituted with delusions as main feature. Delusions are caused in cases of substance- abuse and
drugs e.g. in consumers of cocaine, amphetamines and drugs like antidepressants, antiparkinson agents
etc Hence, it is important to carefully compare the symptoms and diagnose the disorder. E.g. delusional
disorder can be distinguished from schizophrenia by the non-bizarre quality of delusions and taking into
account the other symptoms of schizophrenia. Somatoform type of delusional disorder is distinguished
from depression by the lack of pervasive quality of depressive mood. Mania also can have in common
persecutory delusions but can be distinguished by the other symptoms accompanying mania like
hyperactivity, poor concentration, uninhibited behaviors etc.
7. Etiology
7.1 Biological approaches
7.1.1 Brain defects and neurological causes
There has been major focus on the role of hemisphere specialisation and the limbic system to find a cause
for delusions. More often than not defects in the left-temporal lobe has been associated with hallucinatory
and delusional states while on the other hand damage in the right parietal lobe has frequently caused two
specific types of abnormal belief, Capgrass Syndrome and Anosognosia. Cummings (1985) emphasised
the role of limbic system and the basal ganglia in the development of delusions and these mediate mood
and motivation. Stuss and Benson (1986) has asserted that damage to the prefrontal areas of the brain has
role in development of delusions and reported in 1990 five cases in which delusions were accompanied
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
by the same due to accident or disease. If we see the role of
neurotransmitters, it has been scientifically proven that excess of
dopamine has been found to cause hallucinations and delusions.
7.1.2 Genetics
Frequently in psychiatry a question that is often raised is whether Delusional Disorders are related to
schizophrenia or mood disorders or whether they represent a separate group of disorders. Studies show
that rates of schizophrenia and mood disorders in relatives of delusional disorder patients does not differ
from the prevalence rates in the general population. Only if they have been related in any way, the
incidences should have shown a higher rate as compared to general population. Thus, this shows that
delusional disorders are a distinct group of disorders (Kendler and Walsh, 1995). Catalano (1993) found
that involvement of genetic variation in the Dopamine D4 receptor gene led to increased vulnerability of
delusional disorder.
7.2 Psychological approaches
Delusional Disorders have been etiologically traced to majorly biological causes. However, some
psychological theories do exist.
7.2.1 Delusional Disorders as a result of Cognitive defect
Several studies have been done to ascertain whether there actually exists a cognitive impairment in belief
formation in patients with delusional disorder as compared to the process of belief formation found in
normal individuals. Various studies have been done in order to find if some kind of anomaly in the
cognitive processes is involved in the formation of beliefs. However, a reasoning defect in deluded
patients has not been evident yet. Thus, it further supports the possibility that actually no defect is present
and the cognitions that produce these delusions are normal.
7.2.2 Delusions and Time sense
Melges and Freeman (1975) proposed a cybernetic model for the formation of delusions which points at
temporal disturbance of formal thought as the primary cause of delusions. Experiencing disintegration of
the temporal sequence of thoughts makes patients feel as if they are losing control which may be labelled
as “mysterious”. This may further lead to anger and fear leading to further deterioration and cause them
to behave in a hostile manner.
7.2.3 Delusions and attention
In 1903, Berze proposed that paranoid patients have attentional defects which serve as causative factor for
delusions.
7.2.3 Delusions and perception
Pavlov (1934) had proposed first theory that asserted that delusion of reference and control were due to
perceptual disturbances, which he felt occurred due to pathological inertness of cells of sensory cortex. To
compensate for this inertness, other cells are hyper aroused, thus leading to irrelevant ideas to find their
way to consciousness. Delusions may develop in patients with hearing deficits (Houston & Royse, 1954).
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
Incidences of visual defects have also been found more in
delusional disorder patients. To prove this, Zimbardo, Anderson
and Kabat (1981) demonstrated that hypnotically induced hearing loss in normal individuals led to higher
scores on the paranoia scale of MMPI.
7.2.4 Freud’s hypothesis
Freud’s psychoanalytical perspective asserts that delusions stem from repressed homosexual tendencies.
He hypothesised this based on a case of a German lawyer. However, his theory has been criticised for
many reasons that include inconsistency, overlooking of facts, inclusion of only 4 kinds of delusions and
that this approach is unscientific and biased.
8. Epidemiology
Epidemiology is defined as the study of the distribution and determinants of diseases in human
populations.
8.1 Prevalence
The rates of prevalence show that delusional disorder is uncommon but not rare. Estimates of general
population show that the prevalence rate is almost 24-30 cases per 1, 00,000 people. The incidence rates
have been estimated to be 0.7-3.0 new cases per 100,000 people. In India, 5% of cases have paranoia out
of all patients with delusions. ( Kala & Wig, 1978)
8.2 Age of onset
Delusional Disorders are most likely to appear during mid-life. Both age of onset and age of admission
peak around age of 40-50.
8.3 Sex differences
Not much difference has been found, with both sexes being affected almost equally. Incidence rates in
females are slightly higher, with 55% of first admission patients being women.
8.4 Other demographic factors
Marital status: 32% cases of delusional disorder were found to be unmarried.
Educational qualification: delusional disorder patients were found to be more poorly educated as
compared to other affective disorders. ( Kendler, 1982)
Premorbid Personality: Patients with delusional disorder are more likely to be extrovert, dominant and
hypersensitive (Bonner, 1951; Johanson, 1964; Retterstol,1966).
9. Treatment
9.1 Pharmacological treatment
Oral neuroleptics like Pimozide are being promoted to be therapeutically specific for delusional disorder
as compared to other psychotic drugs. Srinivasan et al, (1994) from India came up with treatment using
trifluperazine, haloperidol, Chlorpromazine and electroconvulsive therapy. Delusional disorder treatment
often involves the use of Atypical (also known as Newer-generation) antipsychotic medicines.
Risperidone, Quetiapine and Olanzapine are some examples of the same.
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
____________________________________________________________________________________________________
9.2 Psychological treatment
There are various psychotherapies available. But in any
psychotherapy for delusional disorder establishing a trusting relationship with the client is the key like
that of any psychotherapy. The therapist must reassure and be compassionate to the client to facilitate the
process of treatment. It has been accepted that to confront the client about his or her delusions is not a
good idea as this can rather make them angry and hostile instead of leading to conviction about the
delusional nature of their beliefs. “Initially, the therapist should neither agree with nor challenge the
patient’s delusions.” (Kaplan and Sadock, 1985). Cognitive therapy has yielded good results when it
comes to reducing delusional thinking by modifying the belief itself, voicing counter-arguments against
their delusional beliefs and develop alternative explanation for their experiences. Beck (1952) and
Chadwick and Lowe (1990, 1994) employed these strategies and reported successful results
10. Summary
Delusional Disorder was initially known as “Paranoia”
Delusional Disorder is thus a rare mental illness, involving delusions, which are mostly non-bizarre
and involve situations that may occur in real life.
Defining delusional disorder has led to a lot of debate regarding the very definition of delusions.
The main aspect of the clinical picture of delusional disorder is the delusional system of thoughts and
beliefs which are rigidly held on to in spite of contradictory evidence.
Diagnosis is done based on DSM IV-TR or DSM-V criteria accompanied by interviews and
administration of psychological tests.
The types of delusional disorder include Erotomanic, Grandiose, Jealous, Persecutory, Somatic and
Mixed.
Biological approaches mainly define the etiology of delusional disorder.
Treatment involves administration of neuroleptics combined with cognitive therapy.
PSYCHOLOGY PAPER No.15: Clinical Psychology
MODULE No.20: Delusional Disorder
