Objective: Explore how clinicians select drug treatment based on symptoms, side effects and patient factors, including patient participation in the process, and the association between these factors and attitudes towards drugs.

Method: A cohort of 166 patients initially treated with risperidone was followed with yearly assessments over 5 years. At the end of the study, 101 patients were evaluated of whom 58 were still treated with risperidone.

Results: More women than men remained in the study, and on the initial medication. The most common reason for medication switch was lack of efficacy. Clinicians and patients agreed well in their global ratings of medication effects and side effects. Robust associations between switch decisions and patient characteristics including symptoms and side effects could not be identified. The effects of switches were rated as better by the clinicians than by the patients. Negative drug attitudes were associated with pronounced positive symptoms (threshold effect), whereas the corresponding association with 'lack of judgment and insight' was linear over the whole range.

Conclusion: The decision-making process appears to have many unknown components, and may benefit from more active patient involvement by using structured clinician and patient rating scales for monitoring the treatment. Such shared decision-making may improve compliance.