According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, the essential feature of delusional disorder is the occurrence of one or more delusions that continue for at least a month. These delusions can lead to social and occupational problems, as others begin to see these individuals as irrational.

It’s critical that assessments of depression, cognition, and mania symptoms are thoroughly completed in order to correctly distinguish delusional disorder from other psychotic disorders, including the various schizophrenia spectrum.

Diagnostic Criteria for Delusional Disorder DSM-5 297.1 (F22)

While the essential feature of this disorder is simply the existence of one or more delusions that occur for at least 1 month, the following are all used to make a correct diagnosis of delusional disorder:

  • The individual has one or more delusions that persist for at least a month or more.
  • Criterion A for schizophrenia is not and never has been met.
  • Aside from the delusion(s) direct effects, functioning is not obviously impaired, and behavior is not noticeably strange.
  • Any manic or major depressive episodes have been brief, compared to the length of the delusional period.
  • The disturbance cannot be attributed to the physiological effects of a substance, another medical condition, or another mental disorder.

The severity of the delusions should be noted and it should also be specified if delusions involve bizarre content, or are clearly implausible. Additionally, there are a few subtypes with specific delusional themes that should be specified:

  • Erotomanic type: This involves delusions about another person being in love with the affected individual.
  • Grandiose type: Individuals with the grandiose type of delusional disorder believe they have a great talent (which is unrecognized) or made a great, important discovery.
  • Jealous type: This involves delusions about his or her lover being unfaithful.
  • Persecutory type: This subtype pertains to individuals with delusions involving their beliefs that they are being conspired against, spied or cheated on, poisoned or drugged, harassed or followed, or generally obstructed in the pursuit of long-term goals.
  • Somatic type: Individuals with the somatic type of delusional disorder have delusions involving bodily functions/and or sensations.
  • Mixed type: There is not one delusional theme that persists over others.
  • Unspecified type: The dominant delusional belief cannot be clearly determined or does not fall into the descriptions of the specific types.

Who Is at Risk of Developing Delusional Disorder DSM-5 297.1 (F22)?

While an individual’s cultural and religious background must be considered during assessment of a possible delusional disorder, there is not one cultural or religious group that is at a higher risk of developing delusional disorder. Furthermore, one gender is not more prone to developing the disorder either, although the jealous subtype is most likely more common in males. The only existential risk factor involves the presence of schizophrenia and schizotypal personality disorder, as there is a significant familial relationship.

Is There Treatment for Delusional Disorder?

While delusional disorder can be a difficult one to treat, affected individuals do have a few options:

  • Psychotherapy: This is typically the most effective treatment for individuals suffering from delusional disorder. The therapist will avoid directly challenging the delusional beliefs and instead concentrate on realistic problems and goals the person has. Then, when a solid relationship has been established between therapist and patient, the therapist can start reinforcing positive behaviors of the individual.
  • Medications: Anti-psychotic medication is the most common form used to treat delusional disorder. However, this treatment approach can be problematic as patients may become suspicious of professionals suggesting the use of medication.

Functional Consequences of Delusional Disorder

The majority of individuals suffering from delusional disorder often appear normal, especially when they are not acting on or discussing their delusions. However, it is possible (though rare) for affected individuals to experience substantial impairment and poor occupational functioning, as well as social isolation.

Differential Diagnosis

  • Obsessive-compulsive and related disorders. In cases that involve an individual feeling that his or her obsessive-compulsive disorder beliefs are true, a delusional disorder diagnosis should not be made, but rather an obsessive-compulsive disorder, with absent insight/delusional beliefs specifier. This remains true for other disorders, such as body dysmorphic disorder.
  • Schizophrenia and schizophreniform disorder. The absence of other characteristics of the active phase of schizophrenia can differentiate delusional disorder from schizophrenia and schizophreniform disorder.
  • Depressive and bipolar disorders and schizoaffective disorder. If delusions only present themselves during mood episodes, the diagnosis is depressive or bipolar disorder with psychotic features. Delusional disorder is to only be diagnosed if the total duration of all mood episodes is brief compared to the period of delusions.
  • Delirium, major neurocognitive disorder, psychotic disorder due to another medical condition, and substance/medication-induced psychotic disorder. Individuals with these disorders may show symptoms that point to delusional disorder (e.g., simple persecutory delusions in major neurocognitive disorder would be diagnosed as major neurocognitive disorder with behavioral disturbance).