Abstract

Dual Diagnosis of Substance Abuse and Schizophrenia: Improving Compliance with Pharmacotherapy

Substance abuse affects approximately half of patients with schizophrenia and can act as a barrier to compliance with antipsychotic medication. Patients may use nicotine, alcohol, cannabis, cocaine or other drugs of abuse in order to overcome symptoms associated with schizophrenia itself or with the side effects of the antipsychotic medications used to treat the underlying illness. The impact of substance abuse for comorbid substance abusers compared with nonabusing schizophrenia patients includes a lower quality of life, increased tardive dyskinesia, increased psychosocial problems, more relationship difficulties, cognitive deficits and even suicide. Patients with a dual diagnosis also tend to have higher relapse rates, higher rates of hospitalization, and by inference, increased healthcare costs. Atypical antipsychotics are recommended for reducing substance abuse in schizophrenia patients and have been shown to be effective in this manner, though no antipsychotic is currently indicated specifically for treating substance abuse in patients with schizophrenia. However, despite the use of atypical antipsychotics in this population, noncompliance remains high and is often associated with rehospitalization or relapse. Long-acting injectable antipsychotic medications increase compliance rates; however, there are limitations to the use of conventional antipsychotic long-acting formulations in this population. Nonpharmacologic interventions such as substanceabuse management skills, training and motivational intervention are also important in reducing substance abuse and increasing compliance with antipsychotic medications. The combination of such nonpharmacologic interventions, along with a long-acting atypical antipsychotic, may be advantageous in treating dually diagnosed patients.

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