Mood disorders are psychological conditions characterized by persistent disturbances in a person’s emotional state, particularly involving prolonged sadness, loss of interest, excessive excitement, irritability, or fluctuations between depression and elevated mood. In counselling psychology, understanding the causes of mood disorders is important because these disorders generally arise from an interaction of biological, psychological, and social factors rather than from a single cause. Biological factors play an important role in the development of mood disorders. Genetic vulnerability is one of the major factors. Individuals having close family members with depression or bipolar disorder may have a greater risk of developing similar conditions. However, heredity does not necessarily determine that a person will develop a disorder; it