[Obsessive-compulsive symptoms in psychotic disorders: pathogenesis and treatment]

Comorbid disorders often occur in psychoses from the schizophrenia spectrum and are an additional burden for patients' quality of life, render treatment and rehabilitation prognosis more difficult and can also contribute to suicidal ideation. Specifically, obsessive-compulsive syndrome (OCS) and OC disorder (OCD) have been reported.

What is known about the epidemiology and pathogenesis and which conclusions can be drawn regarding the diagnostics and treatment?

This review evaluated current reports on comorbid OCS during different stages of psychotic disorders, starting with the at-risk mental state (ARMS) via the first manifestation and up to chronic courses. The focus was on pharmacological and psychotherapeutic consequences.

Patients with ARMS suffer much more often from OCS than the general population. The prevalence is even higher in patients with a first manifestation of psychosis. During the chronic courses ca. 30% of patients are affected by comorbid OCS and 12% fulfill the diagnostic criteria of a OCD. The pathogenesis can most likely be explained by a genetic disposition in the glutamatergic system, shared structural and functional abnormalities of cortical and subcortical structures, pharmacological influences and psychosocial stressors.

Clozapine and other antipsychotics may induce or aggravate OCS in a dose-dependent manner. In order to alleviate symptoms clozapine should be reduced to a minimally sufficient level. This can be attempted through combination, for example with dopaminergic antipsychotics. In general, serotonergic antidepressants can be added. Cognitive behavioral therapy should be offered to every patient with comorbid OCS. For future research multimodal longitudinal studies investigating the efficacy of interventions and aimed at the subjective level will be important.