Current Treatments for Delusional Disorder

Delusional disorders form part of the spectrum of psychotic disorders in psychiatry. They are poorly understood in practically every aspect of their nature, including cause, phenomenology, prevalence, comorbidity, course, treatment, and prognosis. The key symptom in delusional disorders is one or more delusions. A cardinal characteristic of delusional disorder, conviction that one is not mentally ill, contributes complexity to the treatment challenges and profoundly affects the therapeutic relationship. Diagnosis and differential diagnosis are critical tasks. Delusional conditions may arise from many sources and, only when the case conforms to the criteria and is clearly idiopathic—is a primary delusional disorder—can we feel confident that the patient suffers from delusional disorder rather than a secondary delusional condition. Adequate treatment follows principles for the treatment of delusions. First line pharmacological treatment for delusional disorder is antipsychotic medication, both first and second-generation agents, and some evidence suggests that clozapine may be effective in certain cases. The assumption in such a formulation is that the delusion(s) encountered in delusional disorders respond as a class of symptoms found in different disorders. Hence, the approach for failed interventions with these agents may be similar to that proposed for the treatment of schizophrenia or other psychotic disorders. Namely, searching for evidence of failure to take medication, inadequate dosing, a missed diagnosis of a substance disorder, medical condition, or even another psychiatric disorder should be considered. For individuals with delusional disorders who are also experiencing comorbid depression or anxiety, the addition of appropriate agents for those symptoms may provide a synergistic strategy for overall effectiveness. Psychotherapy is another important clinical tool. Cognitive behavioral therapy focusing on different aspects of delusions (i.e., anxiety, reasoning biases, faulty logic, etc.) has demonstrated some value for at least short-term improvement. Various techniques may be useful in allying with the patient and supplying means to assist in managing their thinking and approach to circumstances and factors that promote delusion formation and encourage actions taken to respond. A significant problem in applying what we know about delusional disorders to treatment is the limited available evidence. Lack of randomized controlled trials, which form the standard in most clinical disorders, is a major shortcoming. Recent observations of compromised cognitive functioning in working memory, attention, and executive function should be replicated with similar standards. Systematic case studies and large series are useful, and a growing effort to be more rigorous methodologically in all contributions including case registries and longer follow-up studies is promising. Nevertheless, our knowledge remains less than optimal. These comments apply not only to pharmacological observations but also to those of neuropsychological and psychotherapeutic studies.