The introduction of second generation antipsychotic (SGA) drugs represents a major advance in the treatment of schizophrenia. Concerns about the metabolic and cardiovascular adverse effects of the SGA, as opposed to first generation antipsychotic (FGA), have been disseminated. The benefits and risks of SGA have been studied with a focus on particular organ systems. Cardiovascular diseases are the leading cause for death in development countries. Weight gain and drug dependence are the risk factors for cardiovascular disease.

Concurrent comorbidity has become the rule among psychiatric inpatients. Unfortunately the majority of the clinical trials with SGA exclude the Dual Diagnosis patients (DDP). There is no evidence for examination of weight change during risperidone long-acting injectable (RLAI) treatment in DDP.

To compare the weight change in RLAI versus FGA-LAI treatment of DDP.

Twenty two DDP (21 (95.4%) males) meeting DSM-IV criteria for Schizophrenic spectrum disorders (median age=29 years [range, 21-39 years]).

BMI was determined by the dividing of weight by the square of height. The BMI was calculated for DDP who were treated by FGA-LAI or by RLAI treatment at baseline and after a period of 3 months.

There were no significant differences between the groups before the treatment (NS). There was no significant weight change as opposed to baseline in each of the groups (NS).

Treatment of DDPs with RLAI is safe and does not increase the middle-term risk of weight change.