Mood disorders are a category of illnesses that describe a serious change in mood. Illness under mood disorders include: major depressive disorder, bipolar disorder (mania – euphoric, hyperactive, over inflated ego, unrealistic optimism), persistent depressive disorder (long lasting low grade depression), cyclothymia (a mild form of bipolar disorder), and SAD (seasonal affective disorder).

Alcoholism and other forms of drug dependence are also related to depression. Dual diagnosis – substance abuse and another psychiatric disorder, usually a mood disorder – is an increasingly serious psychiatric concern. Whether drug abuse causes depression, depression leads to drug abuse, or both have a common cause, a vicious spiral ensues when addicts use the drugs to relieve symptoms the drugs have caused. Cocaine and other stimulants act on neurotransmitters in the brain’s pleasure center, causing elation that is followed by depression as the effect subsides. Sometimes what appears to be major depression clears up after abstinence from alcohol or drugs. People with serious mood disorders also have twice the average rate of nicotine addiction, and many become depressed when they try to stop smoking.