Many patients with schizophrenia will relapse despite uninterrupted antipsychotic (AP) long-acting therapy (LAT). This exploratory analysis examined variables associated with relapse despite ensured adherence to LAT. This was a post-hoc exploratory analysis of a 1-year study of risperidone long-acting injection in patients with stable schizophrenia or schizoaffective disorder (NCT00297388; N=323). Patients were discontinued from previous oral APs and randomly assigned to biweekly intramuscular injections of risperidone long-acting injectable 50 (n=163) or 25 mg (n=161) for 52 weeks. Cox proportional hazards regression models examined variables putatively associated with relapse. A total of 59/323 (18.3%) patients relapsed over 12 months despite continuous AP LAT. Variables associated with the risk of relapse included illness duration (6.0% increase each year; P=0.0003) and country (Canada vs. USA, 4.7-fold risk increase; P=0.0008). When illness duration was further categorized as ≤5, 6–10, and >10 years, patients with an illness duration of >10 versus ≤5 years were at greatest risk of relapse (>10 vs. ≤5 years associated with a 4.4-fold increase in the risk of relapse; P=0.0181). Findings suggest that patients with more chronic illness have a greater risk of relapse despite ensured treatment adherence, supporting the need for early intervention to prevent the deleterious effects of chronicity.
aJanssen Scientific Affairs
bJanssen Research & Development, LLC, Titusville, New Jersey
cSaint Louis University School of Medicine, St Louis, Missouri, USA
Correspondence to Larry Alphs, MD, PhD, Janssen Scientific Affairs, LLC, 1125 Trenton-Harbourton Road – A32404, Titusville, NJ 08560, USA Tel: +1 609 730 3693; fax: +1 609 730 3125; e-mail: firstname.lastname@example.org
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Received October 29, 2015
Accepted February 10, 2016