Risperidone versus other antipsychotics for people with dual diagnosis of a psychiatric disorder and an alcohol or drug use disorder
What is dual diagnosis?
Dual diagnosis is a term used to describe people who have both a psychiatric disorder and an alcohol or drug use disorder. Up to 75% of people with a serious mental illness (SMI) are dual diagnosis. It has been suggested that one of the reasons behind the high levels of substance use in people with SMI is due to ‘self-medication’, with patients taking additional drugs in order to counter their distressing symptoms. People with a dual diagnosis have been shown to have more complications in their treatment, including higher rates of relapse and re-hospitalisation, more contact with legal and forensic services, higher levels of psychotic symptoms, more risk-taking behaviour, greater levels of side-effects to antipsychotics and lower medication adherence. Antipsychotics are the main treatment for SMI. It has been suggested that second-generation antipsychotics (SGAs) such as risperidone may be superior to older, first-generation antipsychotics (FGAs) in improving negative affective states, reducing drug craving, improving subjective well-being, and may lead to fewer side-effects and hence greater medication adherence. Such improvements in symptoms may lead to less self-medication with alcohol and drugs, and improved overall mental states. However it remains unclear to what extent risperidone, one of the first atypical antipsychotics to be manufactured, is superior to other antipsychotics for dual diagnosis.
Who may be interested in this review?
Mental health care practitioners who treat people with SMI and dual diagnosis, and who prescribe antipsychotics for these conditions. People who use mental health services and their families who may be involved in their treatment and care.
What does this review aim to answer?
How effective and safe is risperidone compared to other antipsychotics for treating people with a dual diagnosis?
Which studies were included in the review?
We conducted searches for relevant randomised studies in January 2016 and October 2017. We found eight randomised controlled trials with 1073 participants who had a dual diagnosis. The majority of participants were adults over 18 years (4 participants were 17 years). Risperidone was compared to clozapine, olanzapine, perphenazine, quetiapine and ziprasidone.
What does the evidence from the review tell us?
We found no great effect favouring risperidone over any of the other comparison medications. Very limited data were available for side-effects; and again, we found no real differences between risperidone and other antipsychotics. Overall the quality of the evidence available was graded as low to very low, and currently there is not sufficient evidence to indicate risperidone is superior or inferior to other antipsychotics in the treatment of people with severe mental illness and co-occurring substance misuse.
What should happen next?
More high-quality research is needed. Future research should include samples sufficiently large to detect meaningful clinical differences in outcomes.