Drug-related disorders are observed in 30–50% of the patients diagnosed with schizophrenia and is therefore an important problem to be adressed in clinical practice. There are many reasons for the overlap between addictive disorders and schizophrenia: the tendency to alleviate antipsychotic-related side effects, the need to decrease anxiety or depression, to interfere with sensory gating defficits etc.

To assess the effects of atypical antypsychotic treatment in decreasing the drug of abuse consumption in a population of schizophrenia diagnosed patients.

A group of 23 patients, diagnosed with schizophrenia and a drug related disorder (dependence 52.1%, polisubstance dependence 17.4%, substance abuse 26%, other 4.5%), according to DSM IV TR criteria, were monitored for 6 months, while being treated with atypical antipsychotics (olanzapine 43.4%, risperidone 34.7%, aripiprazole 17.4%, amisulpride 4.5%), using Positive and Negative Syndrome Scale for Schizophrenia (PANSS), Clinical Global Impressions (CGI) and Inventory of Drug Taking Situations (IDTS) every 4 weeks.

The evolution of IDTS scores were not parallel to the PANSS evaluations: while the psychotic symptoms decreased continuously during the 6 months of the study (-40.5% at week 12 and -67.5% at endpoint), the IDTS decreased initially (- 33.2% at week 12) but increased slightly to the end of the study (-31.2% at endpoint). The CGI-I score has a decrease of 50.4% at week 12 and of 55.6% at week 24.

The evolution of drug related disorders during the atypical treatment of schizophrenia doesn’t correlate with the severity of psychosis and necessitates a specific management.