Factors and motives associated with drop-out in an ambulatory service for patients with psychotic disorders.

The aim is to study motives and factors associated with treatment drop-out in an ambulatory psychiatric service, which integrates medical, social, familial and rehabilitation treatments. Only 9% of the psychotic patients dropped out, whose motives were non-compliance with medication and unawareness of illness, and the associated factors were comorbidity of substance abuse, social isolation and male gender.

Pharmacokinetic drug interaction potential of risperidone with cytochrome p450 isozymes as assessed by the dextromethorphan, the caffeine, and the mephenytoin test.

Two published case reports showed that addition of risperidone (1 and 2 mg/d) to a clozapine treatment resulted in a strong increase of clozapine plasma levels. As clozapine is metabolized by cytochrome P450 isozymes, a study was initiated to assess the in vivo interaction potential of risperidone on various cytochrome P450 isozymes. Eight patients were phenotyped with dextromethorphan (CYP2D6), mephenytoin (CYP2C19), and caffeine (CYP1A2) before and after the introduction of risperidone.