Patients in every stage of the psychosis continuum can present with negative symptoms. While no treatment is currently available to address these symptoms, a more refined characterization of their course over the lifetime could help in elaborating interventions. Previous reports have separately investigated the prevalence of negative symptoms within each stage of the psychosis continuum. Our aim in this review is to compare those prevalences across stages, thereby disclosing the course of negative symptoms.
We searched several databases for studies reporting prevalences of negative symptoms in each one of our predetermined stages of the psychosis continuum: clinical or ultra-high risk (UHR), first-episode of psychosis (FEP), and younger and older patients who have experienced multiple episodes of psychosis (MEP). We combined results using the definitions of negative symptoms detailed in the Brief Negative Symptom Scale, a recently developed tool. For each negative symptom, we averaged and weighted by the combined sample size the prevalences of each negative symptom at each stage.
We selected 47 studies totaling 1872 UHR, 2947 FEP, 5039 younger MEP, and 669 older MEP patients. For each negative symptom, the prevalences showed a comparable course. Each negative symptom decreased from the UHR to FEP stages and then increased from the FEP to MEP stages.
Certain psychological, environmental, and treatment-related factors may influence the cumulative impact of negative symptoms, presenting the possibility for early intervention to improve the long-term course.
From the Department of Psychiatry, McGill University, and Douglas Mental Health University Institute, Montreal.
Supported, in part, by the following awards from the Fonds de Recherche du Québec – Santé: doctoral award (Dr. Sauvé), Research Scholar salary awards (Drs. Brodeur and Shah), and Research Chair (Dr. Lepage).
Original manuscript received 11 May 2017, accepted for publication subject to revision 27 June 2017; revised manuscripts received 16 July and 12 September 2017.
Correspondence: Martin Lepage, PhD, Douglas Mental Health University, FBC Pavilion, 6875 Blvd. LaSalle, Verdun, Québec, H4H 1R3, Canada. Email: email@example.com
Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.harvardreviewofpsychiatry.org).