Abstract
Seasonal affective disorder (SAD) is typically associated with winter; however, its less common variant, summertime depression, presents with depressive episodes during the summer months. We report a case of a 46-year-old male patient with recurrent summertime depressive episodes characterized by low mood, fatigue, anhedonia, insomnia, and loss of appetite, each resolving with the onset of the winter season. Our patient's history of summertime depression aligned with the atypical SAD symptoms, including irritability and weight loss, commonly associated with non-seasonal depression. A diagnosis of major depressive disorder, moderate severity, with a seasonal pattern was confirmed using the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision criteria, and the Seasonal Pattern Assessment Questionnaire. The patient was initiated on desvenlafaxine 50 mg once a day with a dose titrated to 100 mg once a day in two weeks, while his previous mood stabilizer oxcarbazepine 600 mg in two divided doses was continued. He achieved remission within four to six weeks with his Hamilton Rating Scale for Depression score decreasing from 18 to seven. Our case underscores the importance of recognizing seasonal patterns in affective disorders within tropical climates, like India, and highlights potential environmental and physiological mechanisms, such as heat stress and immune responses, contributing to summertime SAD.