Background: Regular physical activity (PA) decreases morbidity in the general population; yet, information about the amount and effects of PA in persons with schizophrenia is scant. To develop interventions to increase PA and to assess its potential benefits in this group, accurate measurement of PA is needed. The purpose of this study was to characterize PA and determine the test-retest reliability and concurrent validity of the Yale Physical Activity Scale (YPAS), a self-report measure, in persons with schizophrenia.
Methods: PA was assessed with the YPAS, a scale of motivational readiness for PA, and accelerometry in middle-aged and older persons with a diagnosis of schizophrenia (n=54) and in a comparison group with no known psychiatric diagnosis (n=27).
Results: On the YPAS measures, persons with schizophrenia reported on average 11 h per week of PA, whereas the non-psychiatric comparison group reported about 32 h per week. Only about 30% of schizophrenia subjects were classified as being regularly active relative to 62% of the comparison group on PA motivational stages of readiness. On the accelerometry measures, the schizophrenia group had lower levels of light activity than the comparison group, but there were no differences in moderate and vigorous activity or sedentary behavior. Only in the comparison group were there significant associations between YPAS and accelerometer variables. Several YPAS scores demonstrated high test-retest reliability in both groups, and concurrent validity was supported between the YPAS and PA motivational stages of readiness.
Conclusions: We found that the YPAS is a reliable measure of PA in schizophrenia for some indices. Although the YPAS demonstrated concurrent validity with other self-report measures, it did not demonstrate concurrent validity when compared to PA measured by accelerometry in persons with schizophrenia. Use of multiple measures, both subjective and objective, is recommended when assessing PA in schizophrenia.