<prompt> Which of the following is a classical symptom of depression?Altered sleep patternWeight lossGuiltDecreased appetite  <response>: Ans: C Guilt Ref: Synopsis of psychiatry-, Kaplan Sadock, 10th editionExplanationDepressionIt is a common psychiatric syndrome characterized by persistent pervasive sad mood,Because of such sad mood, the person might feel guilty, which in turn gives rise to thoughts like worthlessness, hopelessness helplessness Cognitive triad of Beck, which in turn put himher at risk of ending life ie., suicide.The other symptoms mentioned in the question do occur in any psychiatric disorder.So, the best answer would be Guilt which is pathognomonic of depression. 