Clinical depression Also called: Major depression Requires a medical diagnosis The persistent feeling of sadness or loss of interest that characterises major depression can lead to a range of behavioural and physical symptoms. These may include changes in sleep, appetite, energy level, concentration, daily behaviour or self-esteem. Depression can also be associated with thoughts of suicide. People may experience: Mood: anxiety, apathy, general discontent, guilt, hopelessness, loss of interest, loss of interest or pleasure in activities, mood swings, or sadness Sleep: early awakening, excess sleepiness, insomnia, or restless sleep Whole body: excessive hunger, fatigue, loss of appetite, or restlessness Behavioural: agitation, excessive crying, irritability, or social isolation Cognitive: lack of concentration, slowness in activity, or thoughts of suicide Weight: weight gain or weight loss Also common: poor appetite or repeatedly going over thoughts Consult a doctor for medical advice