Depression, leads to sustained moods of sadness, loss of interest in day to day activities, low self esteem, disturbed sleep patterns and poor energy levels.

Bipolar disorder leads to fluctuations in moods that swing from low to high and back again in varying degrees. The two extremes of this disorder are mania and depression.

Schizophrenia impacts a person's ability to think clearly and distinguish fantasy from reality. The two main pillars of schizophrenia are delusion and hallucinations.