A mood disorder is a pattern of illness due to an abnormal mood. Nearly every patient who has a mood disorder experiences the "lows" of depression at some time, but some may also have the "highs" of mania. Many, but not all, mood disorders are diagnosed on the basis of a mood episode. Most patients with mood disorders will fit into one of the codeable categories listed below.
Mood disorders in general are quite prevalent with about 1 in 10 being affected. Depression is real and it is serious. It's more than "having a bad day." Depressed individuals can't simply wake up one day and "shake it off." It is a medical condition every bit as serious as any other medical condition and should be treated as such.
"Mood" should not be confused with "affect," as they are two different things defined separately in the DSM-IV-TR. The DSM-IV-TR defines the two as affect being "...the subjective or expression of a feeling state (emotion)...in contrast to mood, which refers to a more pervasive and sustained emotional 'climate,'affect refers to more fluctuating changes in emotional 'weather.' The person may be unaffected by happy moods, and just stay in a state of sorrow. Their mood will not lift, no matter who is around them. They are emotionally unresponsive.
Mood disorders pertain to both unipolar and bipolar disorders. Most are correlated with a mania and a depressive mood.
In unipolar disorders, the patient suffers from only severe depression. The person usually is on the low end of sad and depressed states of their mood.
In bipolar disorders, the person experiences both manic highs and depressive lows.
Certain prescription drugs can lead to mood disorders. These prescription drugs include: corticosteroids, levodopa (Parcopa and other drugs used to treat Parkinson’s disease), and methylphenidate (Ritalin and others, commonly used for treating attention deficit disorder) can trigger mania in bipolar disorder (2009). Other drugs, including some used to treat high blood pressure and cancer, have been known to cause depression. Prescription drugs do have side effects but unfortunately they can lead to mood changes as well. Brain trauma in an individual can lead to a alteration in a person’s mood (2009). Mood disorders are difficult to detect in milder forms because there is no blood or laboratory tests (2009).