The longitudinal relationship between mental health disorders and chronic disease for older adults: a population-based study Chun-Min Chen 1 , I-Chen Lee 2 , Yung-Yu Su 3 , Judy Mullan 4 and Herng-Chia Chiu 1,2 1 Research Education and Epidemiology Center, Changhua Christian Hospital, Changhua, Taiwan 2 Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University, Kaohsiung, Taiwan 3 Department of Long-term Care, National Quemoy University, Kinmen, Taiwan 4 Graduate School of Medicine, University of Wollongong, New South Wales, Australia Correspondence to: H.-C. Chiu, PhD, E-mail: chiu@kmu.edu.tw; 345058@cch.org.tw Objective: Although mental health disorders in older adults are common, their relationship with chronic disease and the influence of chronic disease on the development of mental health disorders over time is not well understood. This longitudinal study investigated the change in status of mental health disorders and chronic disease, as well as their interrelationships, over time. Methods: Participants included community-dwelling older adults living in Taiwan, aged 65 years or older, who completed six waves of survey interviews. Mental health disorders were scored using the Short Psychiatric Evaluation Schedule, and chronic disease(s) status was recorded during consecutive biennial data collection waves. The autoregressive latent trajectory model and parallel latent growth curve model were used for data analysis. Results: The study findings suggest that in older people pre-existing mental health disorders and/or chronic disease(s) will predispose them to developing significantly more mental health disorders and/or chronic diseases respectively. The study findings also suggest that pre-existing mental health disorders can significantly contribute to the development of chronic disease over time, and that pre-existing chronic disease(s) significantly can contribute to the development of mental health disorders over time, indicating a reciprocal interrelationship. Conclusions: Our study findings suggest that it in addition to monitoring and treating chronic disease(s) in older people, it is also important to monitor and treat their mental health disorders. Doing so will result in overall better health outcomes and will facilitate a better quality of life as they age. Copyright # 2016 John Wiley & Sons, Ltd. Key words: mental health disorders; chronic diseases; change trajectory; elderly History: Received 01 March 2016; Revised 24 June 2016; Accepted 08 July 2016; Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/gps.4561 Introduction It is well known that chronic disease may have a negative effect on the mental health and well-being of older adults (Black et al., 1998; Chapman et al., 2005; Cole and Dendukuri, 2003). It is not surprising, therefore, that mental health disorders are common in older adults (Stordal et al., 2003) who suffer from chronic disease. The empirical evidence generally supports the hypothesis that chronic disease(s) increases the risk of experiencing mental health disor- ders (Bisschop et al., 2004; Wilhelm et al., 2003), and that the more serious the chronic disease(s) the more serious the mental health disorders (Wulsin et al., 1999). Results from both cross-sectional and longitu- dinal studies have confirmed that older people with chronic diseases reported more symptoms of mental health disorder, as compared to those without chronic Copyright # 2016 John Wiley & Sons, Ltd. Int J Geriatr Psychiatry 2016 RESEARCH ARTICLE