Delusional Disorder

Background

• Delusional disorder is characterized by the presence of delusion(s), or false belief(s), held firmly despite counterevidence or implausibility. Other manifestations of psychotic disorders, such as disorganized thinking, grossly disorganized or abnormal motor behavior, and negative symptoms are absent.
• Typical thematic content of the delusions include persecution (or paranoia), jealousy (infidelity), somatic complaints, grandiosity, erotomania, or a mixture of these themes.
• Individuals with delusional disorder may suffer some impairment in social and occupational functioning related to the delusion, but they are generally able to remain highly functional, and may not come to medical attention unless for another medical concern or if required for legal or criminal reasons.

Evaluation

• Evaluate patients with delusional thoughts carefully for alternative causes.
  • Presentations of other psychiatric disorders, such as specific phobias, anxiety, obsessive compulsive disorder (OCD), and factitious disorder may be difficult to distinguish from delusional thinking.
  • Persistent delusional thoughts may be seen with other psychiatric conditions including brief reactive psychosis, schizophrenia, affective disorders, mania, substance use disorders, and substance toxicity.
  • Delusions can also be symptomatic of other neurophysiological conditions, such as dementia, temporal lobe epilepsy, Huntington disease, Parkinson disease, multiple sclerosis, and traumatic brain injury.
• The diagnosis of delusional disorder is made clinically based on the presence of a persistent (> 1 month) and steadfast false belief despite counterevidence or implausibility, no other signs of psychotic disorder, and after alternative diagnoses are ruled out.
• Use formal criteria such as the ICD-10 criteria or Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for the diagnosis.

Management

• Individuals with delusional disorder may be unlikely to seek psychotherapeutic treatment, as most do not view their delusions as unreasonable.
• Consider medication and psychotherapy for treatment of delusional disorder.
  • Consider first-generation (typical) or second-generation (atypical) antipsychotics as a first-line medication option for most psychotic disorders, including delusional disorder. When selecting an antipsychotic, review its adverse effect profile, particularly motor side effects, metabolic side effects, and cardiovascular side effects, and how these may affect individual patients.
  • Consider cognitive behavioral therapy or cognitive analytic therapy as adjuncts to medication management.
• Treat comorbid psychiatric and medical conditions, which are common in patients with delusional disorder, such as anxiety, depression, and substance abuse.