The concurrence of psychoactive substance use and schizophrenia is important in its effect on therapeutic responses and patient prognosis. The prevalence of these disorders depends on the methodology used:retrospective studies and those in which drug consumption information was not collected in a structured way present a prevalence of disorders due to substance use between 3-22%.When this information is gathered systematically, the prevalence goes up to 30-50%. Between the variables that predict a high risk of disorders due to substance use we found: young adult male, first hospital admittance at a young age, greater frequency of hospital re-admittance, better previous social adaptation to the disease and higher frequency of violent and impulsive behaviour.We try to determine the association of sociodemographic variables and the prevalence of disorders due to substance use.

331 schizophrenic patients admitted to the Psychiatric Ward of Conxo Hospital.Among these subjects, determination was made of the existence of comorbid disorders due to substance use.A descriptive analysis was carried out based on categorical variables using SPSS.

23 patients presented comorbidity(7%).The overall sample of schizophrenic subjects consisted of 93% males, however, the subjects with comorbidity were 100% male.With respect to marital status, there were a greater proportion of single patients with comorbidity(95%).There was a higher proportion of institutionalized patients in the group with comorbidity and a lower level of education. The comorbid group included more subjects who were unemployed.

schizophrenic patients with comorbidity are single men with poor social capacity.It´s important that we collet the drug consumption information by structured way.