Systematic Review Links Negative Symptoms in Schizophrenia to Lower Quality of Life and Function
Key Clinical Summary
- A systematic review of 18,871 participants from 68 studies assessed the impact of negative symptoms on health-related quality of life (HRQoL) and functional outcomes in individuals with schizophrenia.
- Negative correlations were observed between the severity of negative symptoms and HRQoL (r = −0.67 to 0.69, median −0.321, mean −0.350) as well as functional outcomes (r = −0.85 to 0.63, median −0.261, mean = −0.24).
- Findings highlight the need for additional research exploring targeted treatment options for negative symptoms.
In individuals with schizophrenia, greater severity of negative symptoms was associated with decreased health-related quality of life (HRQoL) and worse functional outcomes, according to a systematic review published in Schizophrenia Research.
Study Findings
The researchers assessed data from 18,871 total participants across 68 studies evaluating the relationship between negative symptom severity and HRQoL or functional outcomes in patients with schizophrenia. Most studies were observational and cross-sectional, with sample sizes ranging from 17 to 1812 participants. Mean participant age with standard deviation ranged from 23.71 ± 4.07 to 55.1 ± 14.5 years.
Across the studies, the Positive and Negative Syndrome Scale (PANSS), Scales for the Assessment of Negative Symptoms (SANS), Brief Psychiatric Rating Scale (BPRS), and Clinical Assessment Interview for Negative Symptoms (CAINS) were most commonly used to assess negative symptoms. The Heinrichs Carpenter Quality of Life Scale (QLS) was most frequently used to measure functional and HRQoL outcomes.
In their review, the investigators reported a consistent, small, negative correlation between the presence and severity of negative symptoms and HRQoL. While individual study correlations varied in direction, pooled median and mean values reflected a modest overall negative association, with correlation coefficients ranging from −0.67 to 0.69 across studies (median −0.321, mean −0.350). A similar association was observed between negative symptoms and functional outcomes (r = −0.85 to 0.63, median −0.261, mean = −0.24).
Conversely, there was a slight, positive correlation between functional outcomes and HRQoL (r = −0.63 to 0.58, median 0.15, mean 0.067).
Clinical Implications
While positive symptoms are often responsive to antipsychotic treatment, negative symptoms have historically been more difficult to manage. The findings of this systematic review highlight the need for targeted therapeutic approaches to treat the negative symptoms of schizophrenia, particularly as HRQoL and functional outcomes may be especially impactful to patients: social engagement, daily activities, and overall well-being are among the outcomes that may be influenced by the negative symptoms of the disorder.
Expert Commentary
First author Allyssa Chan, BSc Candidate, Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada, senior author Roger S. McIntyre, MD, FRCPC, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada, and study coauthors noted that the review may have been limited by several methodological factors, including the heterogeneity in antipsychotic exposure and treatment phase across the included studies.
The authors emphasized that “further research is needed to investigate the neurobiology of negative symptoms, and to develop and evaluate pharmacological and non-pharmaceutical interventions, including mechanistically-informed psychotropic agents, for treating negative symptoms, and ultimately improving patient-centered outcomes.”
