Everyone feels down or euphoric from time to time, but this is different from having a mood disorder such as major depressive disorder or bipolar disorder.Mood disorders are extended periods of depressed, euphoric, or irritable moods that in combination with other symptoms cause the person significant distress and interfere with his or her daily life, often resulting in social and occupational difficulties.Consequently, the research presented below was largely based on a similar, but not identical, conceptualization of mood disorders drawn from the (APA, 2000).
Bipolar II Disorder is characterized by single (or recurrent) hypomanic episodes and depressive episodes.
Another type of BD is cyclothymic disorder, characterized by numerous and alternating periods of hypomania and depression, lasting at least two years.
To meet criteria for PDD, a person cannot be without symptoms for more than two months at a time. If someone meets criteria for an MDE during a PDD episode, the person will receive diagnoses of PDD and MDD. Bipolar I Disorder (BD I), which was previously known as manic-depression, is characterized by a single (or recurrent) manic episode.
A depressive episode is not necessary but commonly present for the diagnosis of BD I.
Although the onset of MDD can occur at any time throughout the lifespan, the average age of onset is mid-20s, with the age of onset decreasing with people born more recently (APA, 2000).
Prevalence of MDD among older adults is much lower than it is for younger cohorts (Kessler, Birnbaum, Bromet, Hwang, Sampson, & Shahly, 2010). Recovery begins within three months for 40% of people with MDD and within 12 months for 80% (APA, 2013).
This means that nearly one in five Americans will meet the criteria for MDD during their lifetime.
The 12-month prevalence—the proportion of people who meet criteria for a disorder during a 12-month period—for PDD is approximately 0.5% (APA, 2013).
To qualify for cyclothymic disorder, the periods of depression cannot meet full diagnostic criteria for an MDE; the person must experience symptoms at least half the time with no more than two consecutive symptom-free months; and the symptoms must cause significant distress or impairment.
was published in 2013, and findings based on the updated manual will be forthcoming.