Behavioural Brain Research 292 (2015) 463–469 Contents lists available at ScienceDirect Behavioural Brain Research journal homepage: www.elsevier.com/locate/bbr Research report The first observation of seasonal affective disorder symptoms in Rhesus macaque Dongdong Qin a,c,∗ , Xunxun Chu a , Xiaoli Feng a , Zhifei Li a , Shangchuan Yang a , Longbao Lü d , Qing Yang e , Lei Pan f , Yong Yin f , Jiali Li a , Lin Xu a,b , Lin Chen c , Xintian Hu a,b,∗ a Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China b CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China c State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China d Kunming Primate Research Center, Chinese Academy of Sciences, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China e Department of Nuclear Medicine, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650101, China f Department of Rehabilitation Medicine, the Fourth Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650021, China h i g h l i g h t s • Short photoperiod led monkeys to display depression-related behaviors. • Monkeys presented with physiological abnormalities during the short photoperiod. • Antidepressant treatment can reverse all of the depression-related symptoms. a r t i c l e i n f o Article history: Received 8 April 2015 Received in revised form 30 June 2015 Accepted 2 July 2015 Available online 8 July 2015 Keywords: Seasonal affective disorder Short photoperiod Rhesus macaque Depression-related symptoms Antidepressant treatment a b s t r a c t Diurnal animals are a better model for seasonal affective disorder (SAD) than nocturnal ones. Previous work with diurnal rodents demonstrated that short photoperiod conditions brought about depression- like behavior. However, rodents are at a large phylogenetic distance from humans. In contrast, nonhuman primates are closely similar to humans, making them an excellent candidate for SAD model. This study made the first attempt to develop SAD in rhesus macaque (Macaca mulatta) and it was found that short photoperiod conditions could lead monkeys to display depressive-like huddling behavior, less sponta- neous locomotion, as well as less reactive locomotion. In addition to these depression-related behavioral changes, the physiological abnormalities that occur in patients with SAD, such as weight loss, anhedonia and hypercortisolism, were also observed in those SAD monkeys. Moreover, antidepressant treatment could reverse all of the depression-related symptoms, including depressive-like huddling behavior, less spontaneous locomotion, less reactive locomotion, weight loss, anhedonia and hypercortisolism. For the first time, this study observed the SAD symptoms in rhesus macaque, which would provide an important platform for the understanding of the etiology of SAD as well as developing novel therapeutic interventions in the future. © 2015 Elsevier B.V. All rights reserved. ∗ Corresponding authors at: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Insti- tute of Zoology, Chinese Academy of Sciences, No. 32 Jiaochang Donglu, Kunming, Yunnan 650223, China. Fax: +86 871 6519 7002. E-mail addresses: qindong108@163.com (D. Qin), xthu@mail.kiz.ac.cn (X. Hu). 1. Introduction Seasonal affective disorder (SAD), also known as winter depres- sion, is a mood disorder in which people who have normal mental health throughout most of the year, but experience depressive symptoms in the winter or autumn year after year [1]. SAD was first described in 1984 [1], and exists in DSM-V (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) as “sea- sonal pattern”, a specifier of either unipolar or bipolar affective http://dx.doi.org/10.1016/j.bbr.2015.07.005 0166-4328/© 2015 Elsevier B.V. All rights reserved.