What Are Mood Disorders?
Four basic forms of mood disorders are major depression, cyclothymia (a mild form of bipolar disorder), SAD (seasonal affective disorder) and mania (euphoric, hyperactive, overinflated ego, unrealistic optimism.)
How Common Are Mood Disorders?
About 20% of the U.S. population reports at least one depressive symptom in a given month, and 12% report two or more in a year. A survey conducted in 1992 found rates of major depression reaching 5% in the previous 30 days, 17% for a lifetime. Bipolar disorder is less common, occurring at a rate of 1% in the general population, but some believe the diagnosis is often overlooked because manic elation is too rarely reported as an illness.
The Relationship Between Psychiatric Disorders and Mood Disorders
Depression is a common feature of mental illness, whatever its nature and origin. A person with a history of any serious psychiatric disorder has almost as high a chance of developing major depression as someone who has had major depression itself in the past.
Alcohol, Substance Abuse and Depression
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.
Personality and Mood Disorders
People are more easily demoralized by depression and slower to recover if they are withdrawn and unreasonably self-critical or irritable, impulsive, and hypersensitive to loss. Most people with major depression also show some signs of anxiety, and 15-30% have panic attacks. As a biological mechanism for coping with danger, anxiety creates a need for help or protection that may give way to despair if it is disappointed. Chronically anxious people may also medicate themselves with alcohol or drugs that can cause depression.
Depression and Physical Illness
Depression is associated with physical illness as well. Some 25% of hospitalized medical patients have noticeable depressive symptoms and about 5% are suffering from major depression. Chronic medical conditions associated with depression include heart disease, cancer, vitamin deficiencies, diabetes, hepatitis, and malaria. Depression also is a common effect of neurological disorders, including Parkinson’s and Alzheimer’s diseases, multiple sclerosis, strokes, and brain tumors. Even moderate depressive symptoms are associated with a higher than average rate of arteriosclerosis, heart attacks, and high blood pressure. Depression can mimic medical illness and any illness feels worse to someone suffering from depression.