Physical activity and fitness in adolescents at risk for psychosis within the Northern Finland 1986 Birth Cohort.
Literature regarding physical activity and fitness among subjects at risk for psychosis especially in adolescents is scarce. This study evaluated the level of physical activity and cardio-respiratory fitness among subjects at risk for psychosis in a relatively large birth cohort sample. The study population consisted of the Northern Finland Birth Cohort 1986 including 6987 adolescents who self-reported their physical activity by responding to a postal inquiry in 2001-2002 at the age of 15-16 years. Their cardiorespiratory fitness was measured in a clinical examination by a submaximal cycle ergometer test. Vulnerability to psychosis was defined in three ways: having a parent with a history of psychosis, having prodromal symptoms of psychosis measured by PROD-screen questionnaire at the age of 15-16 years or having actually developed psychosis after the field study (in 2002-2005). The Finnish Hospital Discharge Register was used to find out about parental and the individual's own psychosis. Those individuals who developed psychosis were more likely to be physically inactive (OR 3.3; CI 95% (1.4-7.9) adjusted for gender, parental socio-economic status, family structure and parents' physical activity) and to have poor cardiorespiratory fitness (OR 2.2; 95% CI 0.6-7.8 adjusted for parental socio-economic status, family structure and parents' physical activity) compared to those who did not develop psychosis. Adolescents who would actually develop psychosis had a relatively low level of physical activity compared to their age mates. General recommendations for physical activity would be important for subjects at risk for developing psychosis in order to avoid detrimental effect of physical inactivity on overall health.