Schizophrenia symptoms in the acute phase are often characterized by hallucinations and delusions, which are usually treatable with medication. However, most patients are still troubled with pervasive cognitive deficits, which include poor memory, impaired information processing, and loss of concentration. Antipsychotic medications have little impact on improving cognition, and other pharmacological approaches towards treating cognitive deficits have demonstrated limited efficacy thus far. Non-pharmacological interventions have been developed to specifically target cognitive symptoms, including cognitive remediation therapy (CRT). This therapeutic approach involves completing tasks designed to train various cognitive functions such as memory, attention, and problem-solving skills. However, CRT has only a small effect on psychiatric symptoms, and improvements are lost over time.
A number of recent meta-analyses have shown that structured exercise can significantly improve positive symptoms, negative symptoms, and social functioning in this population. A meta-analysis study combined the data from ten independent clinical trials with a total of 385 patients diagnosed with Schizophrenia. According to a new study from University of Manchester researchers, around 12 weeks of aerobic exercise training can significant improve patients’ brain functioning. The research showed that patients who are treated with aerobic exercise programs, such as treadmills and exercise bikes, in combination with their medication, will improve their overall brain functioning more than those treated with medications alone. There was also evidence among the studies that programs, which used greater amounts of exercise and those which were most successful for improving fitness, had the greatest effects on cognitive functioning.
Furthermore, by increasing cardiorespiratory fitness and metabolic health, exercise may also reduce the physical health problems associated with Schizophrenia, such as obesity and diabetes, which contribute towards reduced life expectancy and adversely affect cognitive functioning. Exercise has also been found to increase hippocampal volume and white matter integrity in healthy older adults and those with Schizophrenia. Additionally, cross-sectional research has demonstrated that physical activity and fitness are associated with better cognitive performance and higher levels of neurotrophic factors which promote brain plasticity. Results from cognitive outcomes showed that exercise improves global cognition significantly more than control conditions. Analyses suggested that supervision from physical health instructors results in better cognitive outcomes. This may be due to increased exercise engagement among participants or better program delivery resulting in more favorable outcomes.
Meta-regression analyses indicated that higher weekly duration of exercise tends to be associated with greater improvement in cognition. The amount that an individual exercises appears to be an important factor for achieving cognitive enhancement. Previous studies have shown that the amount of exercise achieved by participants during an intervention is a significant predictor of cognitive improvements. Additional studies have previously examined the relative influence of exercise duration, frequency, and intensity on cognitive improvements following a 12-week exercise program. The result indicated that exercise intensity was the best predictor variable. This also suggests that aerobic exercise may be more effective for cognition in Schizophrenia than yoga, which previous meta-analyses have found to only be effective for long-term memory.
This meta-analysis study indicated that exercise has similar effects on cognition in Schizophrenia to CRT. Individual studies have shown significantly greater improvements from combining CRT with aerobic exercise for various cognitive subdomains, along with significantly greater reductions in negative symptoms of Schizophrenia. There is also some preliminary evidence supporting the role of brain-derived neurotrophic factor (BDNF) as a mediating factor for cognitive improvements from exercise.
The two other domains, which showed significant changes in response to exercise, were attention and working memory. Since these factors are strong predictors of functional recovery after a first episode of Schizophrenia, implementing exercise interventions from the early stages of illness may facilitate functional recovery. Indeed, exercise may confer even greater benefits in the early psychosis, as cognitive enhancement interventions are more effective at this time than later in the illness. Consistent with this, three recent studies in young patients with first-episode psychosis (aged 23–26) have observed large cognitive improvements from moderate/vigorous exercise after just 10–12 weeks. With the currently limited evidence, it is unclear whether this high level of responsiveness to exercise among first-episode patients is due to their younger age or their earlier stage of illness.
References:
Firth, J., Stubbs, B., Rosenbaum, S., Vancampfort, D., Malchow, B., Schuch, F.,…Yung, A.R. (2016). Aerobic exercise improves cognitive functioning in people with schizophrenia: a systematic review and meta-analysis. Schizophrenia Bulletin. DOI: 10.1093/schbul/sbw115
Jonathan Torres, M.S.
WKPIC Doctoral Intern
(Director’s Note: We have come to our final Friday Factoids post from the 2015-2016 intern class. Stay tuned for the first offerings of the 2016-2017 crew!)