While most treatments have had “statistically significant” success in clinical trials, no common psychiatric or psychological treatments improve what are termed “negative” symptoms of schizophrenia at levels that are “clinically meaningful,” according to a meta-analysis in Schizophrenia Bulletin.
Led by King’s College London researchers, the study stated that there has been a great deal of focus on treating, and some degree of success in reducing, “positive” symptoms of schizophrenia such as hallucinations and delusions. However, less attention has been paid to whether common treatments are helping reduce or improve “negative” symptoms such as “diminished expression of affect,” disengagement, disinterest, social withdrawal, and impaired functioning in daily tasks.
The researchers searched for all randomized-controlled trials of interventions for negative symptoms in schizophrenia published before December of 2013. They examined 168 trials involving 6,503 patients in treatment arms and 5,815 patients in placebo groups.
The researchers found that virtually every major treatment approach — atypical antipsychotics, antidepressants, glutamatergic medications, drug combinations, and also psychological interventions — all helped reduce negative symptoms at “statistically significant” levels. And they also stated that there was, “No evidence of publication biases found.” Only first generation antipsychotics and brain stimulation techniques failed to produce statistically significant outcomes.
However, the impacts of the “effective” treatments, though statistically measurable, were generally so small that they were not truly meaningful when evaluated for their actual impacts on people’s “level of functioning or quality of life,” the authors wrote.
“Although some statistically significant effects on negative symptoms were evident, none reached the threshold for clinically significant improvement,” they concluded.
Fusar-Poli, Paolo, Evangelos Papanastasiou, Daniel Stahl, Matteo Rocchetti, William Carpenter, Sukhwinder Shergill, and Philip McGuire. “Treatments of Negative Symptoms in Schizophrenia: Meta-Analysis of 168 Randomized Placebo-Controlled Trials.” Schizophrenia Bulletin 41, no. 4 (July 1, 2015): 892–99. doi:10.1093/schbul/sbu170. (Abstract)