Delusional Disorder DSM-5 297.1 (F22)

Delusional Disorder DSM-5 297.1 (F22)

DSM-5 Category: Schizophrenia Spectrum and Other Psychotic Disorders


Delusional disorder is one of the less common psychotic disorders, in which patients have delusions but not the other classical symptoms of schizophrenia (thought disorder, hallucinations, mood disturbance or flat affect). There have been some changes in diagnostic criteria for this condition in the new edition of the Diagnostic and Statistical Manual of Mental Disorders, intended to improve the reliability and stability of the diagnosis and facilitate consistent treatment (American Psychiatric Association, 2013).

A delusion is a belief that is held with strong conviction despite evidence disproving it that is stronger than any evidence supporting it. It is distinct from an erroneous belief caused by incomplete information (misconception or misunderstanding), deficient memory (confabulation) or incorrect perception (illusion). The psychiatrist and philosopher Karl Jaspers proposed 3 criteria for delusional beliefs in 1913: certainty (the belief is held with absolute conviction), incorrigibility (the belief cannot be changed with any proof to the contrary) and impossibility or falsity (the belief cannot be true) (Jaspers, 1967). Delusions are associated with a variety of mental and neurological disorders, but are of diagnostic importance in the psychotic disorders.

Symptoms of Delusional Disorder

Delusions are generally categorized in 4 groups: bizarre, non-bizarre, mood-congruent and mood-neutral. Bizarre delusions are strange and implausible, such as being vivisected by aliens, while non-bizarre delusions are possible but unlikely, such as being under surveillance. Mood-congruent delusions are false beliefs that are consistent with the patient’s mood if disordered, such as power and influence with mania and rejection and ostracism with depression. Mood-neutral delusions are not related to the patient’s mood, such as having two heads or one arm.

Delusions have a great variety of themes, but certain recurrent themes have been identified (Spitzer, 1990). These include delusions of control, mind-reading, thought insertion, reference, persecution, grandeur, self-accusation, jealousy (Othello syndrome), romance or sexual involvement (erotomania), somatic change or disease or death (Cotard syndrome). Somatic delusions are associated with mood disorders and organic dementias, and may constitute their own diagnostic entity (body dysmorphic disorder) (Spitzer, 1990), while grandiose or persecutory delusions are often cardinal symptoms of schizophrenia and related disorders (Freeman, 2004).

Munro identified 10 characteristics of delusions (Munro, 1999). The patient expresses the delusional belief(s) with unusual force and persistence, and the belief or beliefs exert and inordinate effect on the patient’s life, often altering or dominating it. Despite profound conviction about the delusion, the patient is often secretive or suspicious in discussing it. Delusional patients tend to be oversensitive and humorless, especially regarding the delusion. The belief is central to the patient’s existence, and questioning it elicits an inappropriately strong emotional reaction. The belief is nevertheless unlikely, and not in keeping with the patient’s social, cultural or religious background. The patient is highly invested emotionally in the belief, and other elements of the psyche may be overwhelmed. If the belief is acted upon, abnormal behavior may result which is out of character for the patient, but which may be understandable in light of the delusion; the belief and behavior are felt to be uncharacteristic by those who know the patient.

Delusional disorder is a primary disorder, with no medical or neurologic cause apparent. It is chronic and may be lifelong, but the delusions are internally consistent and logically constructed. Although the logic of the delusion may be abnormal, general logical reasoning is unaffected, and there is no general disturbance of behavior. Abnormal behavior, if it occurs, is specifically related to the delusional belief. The patient has a heightened sense of self-reference, and trivial or nonspecific events assume great importance through connection to the delusional belief (Munro, 1999).

The causes of delusional thinking are unknown. Morimoto et al. compared patients with delusional disorder to schizophrenics and age-matched normal controls (2002). Patients with delusional disorder had greater sensitivity to small doses of the dopamine-blocking neuroleptic haloperidol than did schizophrenic patients. Plasma levels of the dopamine metabolite homovanillic acid (HVA) were higher in patients with delusions of persecution than in controls, but not in patients with delusional jealousy, and elevated HVA levels decreased with haloperidol treatment. Certain polymorphisms or gene variants associated with the DR2 and DR3 dopamine receptors and the enzyme tyrosine hydroxylase involved in dopamine synthesis were significantly more common in delusional disorder than in schizophrenia or normal controls. These findings suggest that delusional symptoms arise from dopaminergic hyperactivity and may have a genetic basis.

Delusional disorder is more common among people with impaired hearing or vision, and with chronic situational stressors (Maina et al., 2001). These may lead to inaccurate perceptions of reality and inappropriate defensive reliance upon them. Devinsky et al. found a significant association between bilateral frontal lobe and right cerebral hemisphere lesions and delusions (2009). They suggested that right hemisphere injury can result in unbalanced left hemisphere overactivity, allowing left hemisphere language centers to “create a story” that cannot be compared to reality by malfunctioning right hemisphere centers. Impaired right-hemisphere monitoring of the relations between self and environment can also allow an exaggerated self-referential character to be imparted to thoughts and beliefs, and impairment of frontal lobe self-monitoring and correction can result in delusional resistance to counterargument and refutation.


Delusional disorder is infrequent in psychiatric practice, possibly because many patients are able to function tolerably well despite their delusions, and perhaps also because those who believe implicitly in their delusions may not feel the need for treatment and may resist the suggestions of others that they seek psychiatric attention. Prevalence is estimated at 24 to 30 cases per 100,000 people, and new cases each year number 0.7 to 3.0 per 100,000. One to 2 per cent of mental health hospitalizations and only 0.001 to 0.003 per cent of first-time psychiatric admissions are due to delusional disorder (Kendler, 1982).

Diagnostic Criteria

Diagnosis of delusional disorder requires the presence of delusions of at least 1 month’s duration. The patient must never have met Criterion A for schizophrenia, which means that delusions must not have been accompanied by most types of hallucinations, disorganized speech (incoherence or derailments into tangents), grossly disorganized or catatonic behavior, or negative symptoms (flattening of affect, muteness, loss of volition). Tactile and olfactory hallucinations may be part of nonschizophrenic delusions, but not auditory or visual ones. Functioning must not be affected except for the immediate consequences of the delusions, such as hiding from imagined pursuers or preparing to confront the supposed lover of one’s wife. Episodes of mood disturbance if present must be much briefer in duration than the delusions: a patient who is despondent all the time because he is sometimes sure that he has cancer is more likely to be depressed than delusional. The delusion(s) must not be due to a general medical condition or to the effects of drug abuse or medication.

Delusions are further classified by type, based on the predominant thene of the delusion. Erotomanic delusions involve the belief that another person, often of higher status, is in love with the patient. Grandiose delusions are those of power, wealth, importance, relationships to famous people, a special relationship to God or even being a deity. The jealous type are delusions that one’s spouse or partner is unfaithful. Persecutory delusions involve conspiracy against or mistreatment of the patient. Somatic delusions are those of illness or deformity. Mixed delusions have more than one theme.

DSM-5 changes the diagnostic criteria for delusional disorder to reflect revision of the diagnostic criteria for schizophrenia. In previous editions of the manual, delusions had to be “non-bizarre”, i.e., having erroneous beliefs related to real life (being followed or poisoned or persecuted) rather than, for example, the iconic delusion of being Napoleon Bonaparte. Bizarre delusions, such as detachment or liquefaction of body parts, can now be identified as manifestations of delusional disorder if they cannot be better explained by conditions such as body dysmorphic disorder or obsessive compulsive disorder. In addition, DSM-5 removes the distinction between delusional disorder and shared delusional disorder, in which two or more individuals share a delusional belief, historically referred to as folie à deux. It was previously difficult to diagnose delusional beliefs in more than one person if the belief in question might ordinarily be widely shared in the patients’ culture, such as demonic possession at certain times in history or the existence of elves in certain countries. The revised criteria simply propose that if two patients strongly espouse an erroneous belief and have the other symptoms described above, then both patients have delusional disorder.

Treatment of Delusional Disorder

Patients with delusional disorder may be difficult to treat, in part because of the centrality of the delusions in their lives and in part because the delusions may not be very disruptive in the absence of other positive or negative psychotic symptoms. The often-formidable internal logic of the delusional system, even if wrong, may also militate against treatment adherence. Put another way, if you believed unhesitatingly that you were President of the United States, or that you were being poisoned, or that your wife had put you in treatment so she could run off with the postman, would you take your medication? A nonconfrontational culturally-sensitive approach to agreed-upon therapeutic goals, that includes the family when possible, is recommended, outpatient in nature except when violence or harm are concerns and aimed at maintaining social function and improving quality of life (Fochtmann, 2005).

Studies of medication treatment are mostly in classes C (series of cases) and D (single case studies) of the evidence-based medicine hierarchy, with little or no class A (randomized controlled trial) or B (systematic but nonblinded or nonrandomized trials) evidence. Studies between 1966 and 1985 involved about 1000 delusional disorder patients, of whom 257 were well-described, and found recovery with antipsychotic drug treatment in 52.6 per cent and improvement in 28.2 per cent, while 19.2 per cent did not improve. Pimozide (68.5 per cent recovery and 22.4 per cent improvement) was better than other typical neuroleptics (22.6 per cent recovery and 45.3 per cent improvement) (Munro, 1995). Studies since 1985 used primarily atypical neuroleptics, such as respiridone (Risperdal), quetiapine (Seroquel) and olanazapine (Zyprexa), in a small number of patients (224 reported, 134 well described). Ninety per cent of patients had symptom improvement while 50 per cent were symptom-free, often after polypharmacy or with other treatment modalities used as well. No differences in response were found between pimozide and other typical neuroleptics, or between typical and atypical antipsychotic agents, but patients with persecutory delusions did worse (50 per cent improvement and no complete recovery) (Freudenmann & Lepping, 2008). Antidepressants, particularly SSRI agents and clomipramine, have been occasionally helpful, mainly with somatic delusions (Hayashi et al., 2004).

Supportive psychotherapy is helpful for most patients, chiefly cognitive treatment that uses Socratic questioning to identify maladaptive thoughts and replace them with more adaptive beliefs, but is careful not to address the unrealistic nature of the delusions too early in the treatment process (Silva et al., 2003). Cognitive behavioral therapy (CBT) and attention placebo control (APC) have been compared in their effect on the Maudsley Assessment of Delusions Schedule (MADS), and both produced improvement, but CBT was more effective in lessening strength of delusional conviction, decreasing affect related to delusional beliefs and diminishing action on the beliefs (O’Connor, Stip & Pelissier, 2007). Training patients in behavioral principles and social skills so that they feel more in control of their situations and are better able to interact with those they think are judging or harming them has been shown to dissipate feelings of powerlessness that reinforce delusions (Liberman, 2008). Some feel that insight-oriented psychotherapy is ineffective or even contraindicated in delusional disorders, but case reports have suggested that patients may sometimes be helped to contain feelings of impotence, badness and hatred, to question their internal view of the world and to accept an alliance with therapists (Liberman, 2008).


American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders, ed. 5. Washington, DC: APA Press.

Devinsky, O. (2009). Delusional misidentifications and duplications: Right brain lesions, left brain delusions. Neurology, 72(1), 80-87.

Fochtmann, L.J. (2005). Treatment of other psychotic disorder. In Sadock, B.A., Kaplan, V.A., Ruiz, P. (Eds). Kaplan and Sadock’s Comprehensive Textbook of Psychiatry, ed. 8. Philadelphia: Lippincott Williams and Wilkins, 1545-1550.

Freeman, D., & Garrity, P.A. (2014). Paranoia: The Psychology of Persecutory Delusions. Hove: Psychology Press.

Freudenmann, R.W., Lepping, P. (2008). Second-generation antipsychotics in primary and secondary delusional parasitosis: outcome and efficacy. J Clin Psychopharmacol, 28(5), 500-508.

Hayashi, H. et al. (2004). Paroxetine treatment of delusional disorder, somatic type. Hum Psychopharmacol, 19(5), 351-352.

Jaspers, K. (1967). General Psychopathology. Baltimore: Johns Hopkins University Press, 106.

Kendler, K.S. (1982). Demography of paranoid psychosis (delusional disorder): A review and comparison with schizophrenia and affective illness. Arch Gen Psychiat, 39(8), 890-902.

Liberman, R.P. (2008). Recovery from Disability: Manual of Psychiatric Rehabilitation. Arlington, VA: Amer Psychiatric Publishing.

Maina, G., Albert, U., Badà, A., & Bogetto, F. (2001). Occcurrence and clinical correlates of psychiatric co-morbidity in delusional disorder. Eur Psychiat, 16(4), 222-228.

Morimoto, K., et al. (2002). Delusional disorder: molecular genetic evidence for dopamine psychosis. Neuropsychopharmacology, 26(6), 794-801.

Munro, A. (1999). Delusional Disorder: Paranoia and Related Illnesses. Cambridge, U.K.: Cambridge University Press.

Munro, A., & Mok, H. (1995). An overview of treatment in paranoia/delusional disorder. Can J Psychiatry, 40(10), 616-622.

O’Connor, K. et al. (2007). Treating delusional disorder: a comparison of cognitive-behavioural therapy and attention placebo control. Can J Psychiatry, 52(3), 182-190.

Silva, S.P., Kim, C,K., Hoffman, S.G., Loula, E.C. (2003). To believe or not to believe: Cognitive and psychodynamic approaches to delusional disorder. Harv Rev Psychiatry, 11(1), 20-29.

Spitzer, M. (1990). On defining delusions. Compr Psychiat, 31(5), 377-397.

Help Us Improve This Article

Did you find an inaccuracy? We work hard to provide accurate and scientifically reliable information. If you have found an error of any kind, please let us know by sending an email to, please reference the article title and the issue you found.

Share Therapedia With Others