Are patients enrolled in first episode psychosis drug trials representative of patients treated in routine clinical practice?

Background: Evidence on efficacy of antipsychotic medications comes primarily from controlled trials which select eligible consenting patients for experimental and regimented treatments, who do not abuse drugs, and are in good general health. Thus, it is not clear to what extent results are generalizable to most individuals treated for a psychotic illness who may not be eligible for such trials. Objective: This study compared characteristics of patients treated in a large randomized trial of persons with early psychosis to a cohort from a large epidemiological study of first episode psychosis. Methods: Included were the 535 patients enrolled in a controlled trial of antipsychotic medication and 179 similarly diagnosed persons from the Suffolk County Mental Health epidemiological study. Drug trial exclusion criteria were used to estimate the number of patients from the epidemiological study who would have been ineligible for the drug trial. The two samples were compared on key characteristics. Results: Thirty-three percent (n=59) of the epidemiological sample did not meet inclusion criteria for the drug trial (due to antidepressant treatment, n=26; current substance abuse, n=18; recent suicide attempt, n=9; and for more than one reason, n=6). There were no significant differences between the two study samples on age of onset, age, gender and premorbid functioning. Drug trial patients had higher Brief Psychiatric Rating Scale (BPRS), slightly lower Clinical Global Impression (CGI), and less formal education than those in the epidemiological study. Conclusions: While some patients in the epidemiological sample would have been excluded from the drug trial, patients in the two studies were similar on several key variables.