This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mood disorders, Subject name: Psychiatry
[{'content': 'Early morning awakening and reduced latency of REM sleep is suggestive of \nSelect and explain. \nA. Delirium, B. Depression, C. Schizophrenia, D. Anxiety', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Disturbance of biological functions is common in depression, with insomnia (or sometimes increased sleep), loss of appetite and weight (or sometimes hyperphagia and weight gain), and loss of sexual drive. The somatic syndrome in depression is characterised by: a. A significant decrease in appetite or weight b. Early morning awakening, at least 2 (or more) hours before the usual time of awakening c. Diurnal variation, with depression being worst in the morning d. Pervasive loss of interest and loss of reactivity to pleasurable stimuli e. Psychomotor agitation or retardation. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no.72', 'role': 'assistant'}]