Definitions and drivers of relapse in patients with schizophrenia: a systematic literature review

Relapse in patients with schizophrenia has devastating repercussions, including worsening symptoms, impaired functioning, cognitive deterioration and reduced quality of life. This progressive decline exacerbates the burden of illness on patients and their families. Relapse prevention is identified as a key therapeutic aim; however, the absence of widely accepted relapse definition criteria considerably hampers achieving this goal. We conducted a literature review in order to investigate the reporting of relapses and the validity of hospitalization as a proxy for relapse in patients with schizophrenia. The primary aim was to assess the range and validity of methods used to define relapse in observational or naturalistic settings. The secondary aim was to capture information on factors that predicted or influenced the risk of relapse. A structured search of the PubMed database identified articles that discussed relapse, and hospitalization as a proxy of relapse, in patients with schizophrenia. National and international guidelines were also reviewed. Of the 150 publications and guidelines identified, 87 defined relapse and 62% of these discussed hospitalization. Where hospitalization was discussed, this was as a proxy for, or a component of, relapse in the majority of cases. However, hospitalization duration and type varied and were not always well defined. Scales were used to define relapse in 53 instances; 10 different scales were used and multiple scales often appeared within the same definition. There were 95 references to factors that may drive relapse, including non-adherence to antipsychotic medication (21/95), stress/depression (11/95) and substance abuse (9/95). Twenty-five publications discussed the potential of antipsychotic therapy to reduce relapse rates-continuous antipsychotic therapy was associated with reduced frequency and duration of hospitalization. Non-pharmacological interventions, such as psychoeducation and cognitive behavioural therapy, were also commonly reported as factors that may reduce relapse. In conclusion, this review identified numerous factors used to define relapse. Hospitalization was the factor most frequently used and represents a useful proxy for relapse when reporting in a naturalistic setting. Several factors were reported to increase the risk of relapse, and observation of these may aid the identification of at-risk patients.