Depression is a mood disorder whereby mood is sad. About 30% of psychiatric cases deal with depression. Both males and females are affected but females are slightly more prone to be depressed. Cause: The biological cause is that there is a decrease in the serotonin neurotransmitter. Signs and symptoms: A simple mnemonic to remember is SIPS CAGE. 1) Sleep - There is late onset of sleep, intermittent awakening and early morning awakening i.e. around 2 hours before the normal waking up time. Rarely, the patient may over sleep. 2) Interest - Patient will have a decrease interest in the daily activities. This can result in social withdrawal, decreased ability to function in occupational and interpersonal areas. At times there is the inability to experience pleasure aka anhedonia . 3) Psychomotor activity - In younger patients, there is slowness in the thinking process and activities also are carried out at a slow pace. In elderly on the other hand, there is restlessness and inc...