Mood disorders, also called affective disorders, are a group of illnesses that have as their distinguishing characteristic an experience of mood that is unusual for the circumstances. Common mood disorders include bipolar disorder, depression, postpartum depression, cyclothymia, schizoaffective disorder, and seasonal affective disorder. Most mood disorders are at least somewhat treatable with drugs and psychotherapy.

Mood disorders in which a single mood exists to an unhealthy degree are called unipolar disorders. Severe depression is an example of a unipolar mood disorder and is relatively common among both adolescents and adults. Depression may be characterized by a number of symptoms, including diminished pleasure or interest, irregular sleep patterns, fatigue, suicidal thoughts, lack of concentration or memory, and delusional guilt. Generally speaking, a person may be diagnosed with depression if four or more of these features have been present for a two-week period, in tandem with either loss of interest or a generally depressed mood.

Mania is another of the unipolar mood disorders. Mania is essentially the inverted state of depression, often characterized by an unrealistically high self-image, a lack of sleep accompanied by little or no fatigue, runaway trains of thought, engaging in potentially harmful pleasurable activities to an alarming degree, distractibility, and an increased agitation of movement. If these symptoms persist for more than a continuous week, are not the result of drug use, and are severe enough to impair social interaction, a diagnosis of mania may result.

Bipolar disorder, also sometimes referred to as manic depression, is a mood disorder in which both the states of mania and depression exist at different times. Someone suffering from bipolar disorder will likely experience a period of mania, followed by a period of depression. These shifts usually follow a set pattern, with mood changes occurring anywhere from once every few months to, in some rare cases, once every few hours. Additionally, for someone suffering from bipolar disorder, characteristics of both a manic and a depressive state may coexist.

Mood disorders are quite common in the modern world, with nearly 1% of the adult population of the United States suffering from bipolar disorder alone. Mood disorders often go untreated for long periods of time, because many people have trouble accepting that they are suffering from an illness, rather than “normal” depression or mania. Luckily, treatment is available, and there is a growing amount of public recognition of mood disorders as illnesses which can, and should, be treated.