Negative symptom correlates of physical activity and sedentary behaviour in schizophrenia


Background: People with schizophrenia tend to engage in less physical activity (PA) than the general population, and experience higher rates of cardiovascular disease and obesity. Symptoms of schizophrenia are heterogeneous, and categorized as Positive, Negative, or Cognitive. Negative symptoms (NS) – deficits in typical function – have been consistently associated with less PA among people with schizophrenia. Certain NS, specifically amotivation, may be more relevant to engaging in goal-directed activities than others. Associations between specific NS and PA have not been reported. A secondary analysis of reliability data for a Health Action Process Approach (HAPA) inventory for PA in schizophrenia examined relationships between symptomology, PA and sedentary behaviour. Methods: 26 participants with schizophrenia or schizoaffective disorder were assessed for symptoms using the Brief Psychiatric Rating Scale (BPRS), the Clinical Global Impression Severity scale (CGI), and the Apathy Evaluation Scale (AES). Participants reported moderate and vigorous PA and sitting time from the previous 7 days using the International Physical Activity Questionnaire, and PA Intentions from the HAPA inventory. Results: Pearson correlations revealed significant associations between high levels of amotivation (AES) and fewer weekly minutes of moderate PA (r=-.41, p=.035) and PA intentions (r=-.56, p=.003). Total BPRS (r=-.56, p=.003), the NS factor of the BPRS (r=.40, p =.045) and CGI scores (r=-.54, p=.004) were also inversely related to PA intentions. Sitting time was related to total BPRS (r=.43, p=.042) and CGI scores (r=.45, p=.032); a similar trend emerged with the AES (r=.38, p=.08). Symptom scales did not significantly correlate with vigorous or moderate-to-vigorous PA. Conclusion: These findings suggest a central role for amotivation as a disease-related barrier to moderate PA in patients with schizophrenia. A larger sample size would allow for more specific analysis of symptomology correlates of PA, which may help tailor PA promotion to the heterogeneous needs of this population.

Acknowledgments: This study was supported by a Canadian Institutes of Health Research (CIHR) operating grant #MOP-115709.