Are Randomized Controlled Trials on Pharmacotherapy and Psychotherapy for Positive Symptoms of Schizophrenia Comparable? A Systematic Review of Patient and Study Characteristics

Abstract

We examined patient and study characteristics of pharmacotherapy and psychotherapy trials to establish whether the effects of these 2 treatment strategies can be compared meaningfully. We inspected all randomized controlled trials included in 2 recent meta-analyses on antipsychotics and psychotherapy in patients with positive symptoms of schizophrenia, searching EMBASE, MEDLINE, PsycINFO, Cochrane Library, and ClinicalTrials.gov. Differences between psychotherapy and pharmacotherapy trials were analyzed with Wilcoxon–Mann–Whitney and chi-square tests. Eighty studies with 18 271 participants on antipsychotic drugs and 53 studies with 4068 participants on psychotherapy were included. Psychotherapy studies included less severely ill patients (P < .0001), with a shorter duration of illness (P = .021), lasted for a longer period (P < .0001), administered the intervention as add-on to antipsychotics (P < .0001), had higher risk of bias in some domains including blinding of outcome assessment (P < .0001), and were funded publicly more frequently (P < .0001). Antipsychotic trials had larger sample sizes (P < .0001) and more study centers (P < .0001), included more males (P = .0001), inpatients (P < .0001), and slightly older patients (P = .031), more often used diagnostic operationalized criteria (P = .006), and were sponsored by pharmaceutical companies. They did not differ in conflict of interest (P = .24). We found key differences between the 2 groups of studies that encompass higher risk of bias in psychotherapy studies and the inclusion of more severe patients in drug trials. These differences imply that study and patient characteristics should be carefully taken into account before considering a network meta-analysis. In the interest of patients, psychopharmacologists and psychotherapists should optimize their treatments rather than seeing them in competition.