Mark has been experiencing sleeplessness, irritability, and a sense of increased energy for a week. there are times when he feels euphoric for no reason and has "racing" thoughts for a week. he most likely suffers from

Mark suffers mostly from bipolar depression, due to the observation of the situation that he had. Bipolar depression is the state where the patient has mood disorder that causes rapid changes in the emotional state of the person. This causes the person to experience mania and even crippling depression.