DOI10.1186/1471-2458-7-155LanguageEnglishKeywordsMedicine, Mental health, Biostatistics, Public health, Longitudinal study, Confounding, Strengths and Difficulties Questionnaire, Epidemiology, Physical activity, Gerontology, Demography, Psychiatry, Physical therapyPublishedJuly 12, 2007Citations172 citationsFWCI9.68