Clinical characteristics influencing age at onset in psychotic disorders

Age at onset of psychosis may carry clinical significance across psychotic disorders and appears to be associated with specific genetic abnormalities.

We used the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) to examine clinical characteristics contributing to age at onset variability in patients with schizophrenia (n = 80), schizoaffective disorder (n = 61), and bipolar disorder with psychotic features (n = 92).

Age at onset did not differ across DSM-IV diagnostic groups. Multiple regression analyses revealed that comorbid lifetime cannabis, but not alcohol, abuse/dependence was associated with a statistically significant 3 years earlier age at onset of psychosis. Patients developed cannabis abuse/dependence an additional 3 years before psychosis. Patients with comorbid lifetime panic disorder also had a 4-year earlier age at onset of psychosis. The effects of panic disorder and cannabis abuse/dependence were independent of one another.

Early onset of psychosis, regardless of the specific DSM-IV diagnosis, is characterized by differential clinical features, notably a history of lifetime cannabis abuse/dependence. Panic disorder comorbidity is also associated with earlier age at onset of psychosis. Our findings indicate that examination of clinical and biological characteristics of patients with psychosis regardless of DSM-IV diagnosis can uncover relevant information.