The risk of abuse/dependence of alcohol or drugs in schizofrenia have been estimed about 4 times the prevalence in general population. This fact difficults the treatment results and efficcacy: more relapses, more treatments withdrawal and poorer prognosis. The aims of our study is to evaluate the effect of Zyprasidone, an atypical antipsychotic with 5HT propierties, in patients with schizofrenia and comorbid substance use disorder in a single, open, prospective-naturalistic design.

36 outpatients were selected with Schizofrenic disorder diagnosis (DSMIV) and abuse/dependence of at least 1 substance in which Zyprasidone was recommended (inneficacy, intolerance of prior treatments,..). They were evaluated clinically and data about actual consum and craving were collected at inicial visit and follow-up monthly (3 to 6 months). Results were analized with SPSS pack.

The mean follow-up period was 3 month. 28 patients finished the evaluation showing a decrease in clinical measures (PANSS, ICG) with good tolerance (only 4 drop-outs associated to indesirable effects). The most frequent drug use disorder was tobacco followed by alcohol and cannabis.The results on number and frequency of drug use shows a slow tendency to reduce at the end of the evaluation as well the craving measures but no significant differences were found.

Our exploratory study with Zyprasidone, althougt metodological limitations, suggests that clinical schizofrenic symptoms can improve but also drug pattern use. Naturalistic studies of schizofrenia with comorbid substance use disorder can be useful to show the efficacy of antipsychotics in real clinical practice