Exercise Boosts Cognitive Function in Schizophrenia

Megan Brooks

August 18, 2016

Exercise can improve cognitive function in people with schizophrenia, a meta-analytic review of published studies indicates.

"Collectively, these studies show that aerobic exercise is effective for improving brain function overall in patients with schizophrenia, with particularly large effects on attention, working memory, and social cognition," Joseph Firth, PhD, doctoral researcher at the Institute of Brain, Behaviour and Mental Health, University of Manchester, United Kingdom, told Medscape Medical News.

"Improving the physical fitness of people with schizophrenia is not only important for physical health but also for mental health and brain functioning," he added.

"Taking part in regular exercise would help people with psychosis and schizophrenia to concentrate more, hold more information in mind, and think more clearly about social situations, all of which would improve their ability to function in the real world and recover from their condition," Dr Firth added.

The study was published online August 11 in Schizophrenia Bulletin.

The analysis included 10 independent clinical trials involving a total of 385 schizophrenia patients. The mean age of participants was 37.3 years, the mean duration of illness 13.4 years, and 56% of the patients were male.

Neurocognitive outcomes data were available for 186 patients assigned to exercise interventions; there were 199 persons in control groups. On average, exercise programs were 12.2 weeks long (range, 4 to 24 weeks), with two to four sessions per week. Sessions lasted 20 to 60 minutes. All focused largely on aerobic exercise, although three also incorporated resistance training.

Exercise significantly improved overall cognitive performance (Hedges' g = 0.33; 95% confidence interval [CI], 0.13 - 0.53; P = .001) with no statistical heterogeneity. The effect size in the seven randomized controlled studies was g = 0.43 (P < .001), with low heterogeneity between studies, the researchers report.

Exercise significantly improved the cognitive domains of working memory (g = 0.39; P = .024), social cognition (g = 0.71; P = .002), and attention/vigilance (g = 0.66; P = .005). Effects on processing speed, verbal memory, visual memory, and reasoning and problem solving were not significant, they note.

Greater amounts of exercise were associated with larger improvements in global cognition (β = .005; P = .065).

"We do not know the exact amount of exercise required to yield the cognitive benefits," Dr Firth said, "although we have found across the 10 studies that those which use greater amounts of moderate to vigorous exercise tend to have the largest benefits. Also, we found that exercise programs which effectively improve patients' fitness tend to have the largest effects on cognition."

The results also show that interventions that were supervised by physical activity professionals were more effective (g = 0.47; P < .001).

"Given the challenges in improving cognition, and the wider health benefits of exercise, a greater focus on providing supervised exercise to people with schizophrenia is needed," the researchers conclude in their article.

Experts Weigh In on "Hot" Topic

Meenakshi Dauwan, MD, and Iris Sommer, MD, PhD, of University Medical Center Utrecht, the Netherlands, who reviewed the study for Medscape Medical News, noted that the efficacy of exercise interventions in schizophrenia is a "very timely and hot topic.

"This study shows promising effects of aerobic exercise on cognitive functioning in schizophrenia. However, the authors do not include studies investigating the effect of neuromotor exercises (eg, tai chi, yoga), while such exercise may be especially helpful in people with schizophrenia," Dr Dauwan and Dr Sommer point out.

A recent meta-analysis they conducted showed that yoga specifically improves the cognitive subdomain of long-term memory in patients with schizophrenia. "Future research needs to explore the potential mechanisms through which different types of exercise interventions can improve cognition in schizophrenia," they concluded.

Lena Palaniyappan, MBBS, PhD, director, Prevention and Early Intervention Program for Psychoses, Western University and Lawson Health Research Institute, London, Ontario, Canada, who also reviewed the study for Medscape, said, "This paper is a rigorous synthesis of the current state of evidence relating to the beneficial effect of exercise on cognition for patients with schizophrenia.

"While not directly addressed in this work, it is important to evaluate this evidence in the context of other beneficial effects of exercise in this population: reducing the impact of metabolic side effects of antipsychotics and improving mood."

Dr Palaniyappan also noted that it is hard to "disentangle the nonspecific effects that arise when providing group training sessions and regular, multiple- times-a-week contact with an instructor. Further, there is no clear dose-response relationship: exercising under supervision seems to help, irrespective of the frequency."

He said it is also important to realize that the trials do not examine the durability of the cognitive gain after stopping the exercise.

"So it is hard to know whether an enduring shift in cognition can be brought about by regular exercise. Nevertheless, the results presented here remind us that multidisciplinary care for schizophrenia can benefit by including a physical training instructor in the care team," Dr Palaniyappan said.

The study had no commercial funding, and the authors have disclosed no relevant financial relationships.

Schizophr Bull. Published online August 11, 2016. Full text

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