Mood disorders are among the most common types of mental disorders in the United States, impacting nearly 44 million American adults each year. Mood disorders affect a person's mood to the point where it disrupts his life. If your significant other or coworkers tells you that you are moody, don't assume this means you have a mood disorder. Everyone shifts moods from time to time, often due to some kind of stimulus in their environment, such as the bad mood of another. Mood disorders range from extreme depression to extreme mania and last for an extended period of time. A little mood shift here and there, even though it may seem to disrupt your life for the moment (or the lives of others!), is harmless.

Depression

Everyone suffers sadness, and all people experience being in a bad mood, but when you say, “I'm depressed today,” that's not the proper description for your suffering. Depression (technically called clinical or major depression) is not a twenty-four-hour bug. It is a serious mood disorder in which there are severe changes in an individual's behavior, emotion, cognition, and physical functions. This overwhelming feeling of sadness and/or worthlessness must last at least two weeks and disrupt the sufferer's daily life to be diagnosed as depression.

The symptoms of depression include a feeling of worthlessness, a lack of desire to do anything, even those things you used to love to do, a feeling of overwhelming sadness, thoughts of death or suicide, a lack of energy, changes in appetite (overeating or not eating), changes in sleeping patterns (inability to fall asleep or sleeping a lot more than usual), difficulty concentrating and making decisions, and a lack of desire to be sociable.

Dysthymia

Dysthymia is another mood disorder. Basically it is a lower level of depression. People with dysthymia suffer similar symptoms of depression, such as a change in appetite, a change in sleeping patterns, a feeling of worthlessness or hopelessness, and a low energy level, over the course of at least two years. However, these symptoms aren't constant all the time. The sufferer may have periods during which she feels re-energized and back to normal. Even though the symptoms are milder, dysthymia still disrupts a person's daily life in that it makes activities more difficult to get through.

Bipolar Disorder

Bipolar disorder (formerly called manic-depressive illness) is a mood disorder in which an individual suffers severe mood swings between depression and mania, with periods of normalcy in between. The symptoms of depression in bipolar disorder are the same as those for depression discussed earlier. Mania is the opposite of depression. It is a period of extreme exhilaration wherein the individual is full of energy, high self-esteem, creativity, and ambition. Those in manic states feel as though they could conquer the world — quite different from depression. Imagine how exhausting and confusing it must be to alternate between two such states.

While it may seem like mania is a good thing, it takes its toll. The individual may suffer restlessness so severe that she may not sleep for days, rapid and dramatic speech (thus the inability to communicate effectively), extreme irritability, the inability to concentrate (thus the inability to finish anything), paranoia, impulsiveness, weight loss, and possibly hallucinations or delusions. Bipolar disorder is diagnosed when a person has a manic episode; otherwise, it would be diagnosed as depression, as the depression side of the disorder is the same as in clinical or major depression.

Cyclothymia

Cyclothymia is a lower level of bipolar disorder. People with cyclothymia suffer mood swings between mania and depression, but they are not as extreme. They will suffer the same symptoms as those with bipolar disorder, but on a milder level. The major difference between one with bipolar disorder and one with cyclothymia is that a person with cyclothymia never experiences a full-blown manic state, nor will he experience a major depressive episode. To be diagnosed, a person must experience these symptoms over the course of at least a two-year period.