About a quarter of patient's admissions ages 18-65 in Abarbanel mental health center (MHC) are with substance abuse (Natan, Gimelfarb, Barak & Baruch, 2005). Concurrent comorbidity has become the rule among psychiatric inpatients. Unfortunately the majority of the clinical trials with Antipsychotic drugs exclude the Dual Diagnosis patients (DDP).

To compare the efficacy, safety, drugs craving and compliance with Risperidone versus Haloperidol treatment of DDP.

Ten DDP (meeting DSM-IV criteria for Schizophrenic spectrum disorders; median age=28 years [range, 20-39 years]) from MHC were randomly assigned to either Resperidone (N=5; mean endpoint dose 5.2 mg/day) or Haloperidol (N=5; mean endpoint dose 6.0 mg/day) treatment.

There were no differences between Resperidone and Haloperidol according to efficacy, safety, drugs craving and compliance in each point of time.

Comparing to start-point in each of the groups: No difference in treatment efficacy between the groups (NS); No weight change during Risperidone treatment (NS) and there was weight gain about 2.6 BMI points (SD=.3) after Haloperidone treatment (p<.05); No differences in drugs craving and compliance between the groups (NS).

Although not significant, 60.0% of DDPs who received Haloperidol (N=3) relapsed compared with 0.0% of the DDPs on Risperidone (Fisher's Exact Test p<.08).

The preliminary results suggest, that treatment efficacy and drugs craving are equal in both groups. Compliance with Risperidone is equal to compliance with Haloperidol. But side effects' profile of Risperidone is more convenient than of Haloperidol.