Cocaine abuse/dependence in schizophrenia

Schizophrenia is associated with a nearly 50% lifetime prevalence of substance usedisorder. Studies suggest that among psychoactive substances, cocaine may be associatedwith particularly poor outcomes in schizophrenia patients. During intoxication and/orwithdrawal, cocaine can induce psychiatric (e.g. grandiose thinking, paranoia, mania,depression, anxiety and impulsivity) and cognitive symptoms (e.g. attention, visualmemory, working memory deficits) in non-psychosis abusers. Moreover, cocaine usetakes its toll on society through increased violence, homelessness and HIV-risk. Althoughthe phenomenon has been less extensively studied, cocaine abuse has also been shown toproduce extrapyramidal symptoms (EPS; e.g. parkinsonism, dyskinesia). In relativenumbers, cocaine abuse / dependence is about ten times more prevalent in schizophrenia,compared to the general population. Schizophrenia patients who abuse cocaine mayaggravate their psychiatric, cognitive, and antipsychotic-induced EPS and show a morefrequent pattern of re-hospitalization, non-compliance, homelessness, and aggressivebehaviour. After reviewing the psychiatric, neurological (extrapyramidal), cognitive andaggressive/violent consequences of cocaine abuse / dependence in non-psychosisindividuals, we will discuss the impact of cocaine use in schizophrenia and theetiological/neurobiological models that have been proposed to explain its use in thesepatients. In addition, we will critically examine the role of antipsychotics aspharmacological treatments for cocaine use disorder in schizophrenia and nonschizophreniaindividuals. The efficacy of integrated psychosocial interventions aimed at relieving substance (cocaine) abuse in schizophrenia will also be discussed.