Depression and bipolar disorders are both characterized as mood disorders in the American Psychiatry Association's Diagnostic and Statistical Manual, or DSM. The DSM is the authoritative manual providing diagnostic criteria of mental disorders. Despite being mood disorders, there are differences between depressive and bipolar disorders. The following describes the symptoms differentiating the disorders
Depressive Disorders
Major Depressive Disorder, or MDD, is the most commonly diagnosed depressive disorder. According to the DSM, the criteria for MDD include a depressed mood or decreased interest or pleasure in things usually enjoyed. Other symptoms include disturbed physical functioning (e.g., insomnia or sleeping too much; significant loss of energy; notable changes in appetite or weight; feeling restless or slowed down) and thinking indicators (e.g., feeling hopeless, worthless or guilty; an inability to concentrate or make decisions; having thoughts of suicide or death). In severe depression, individuals may experience hallucinations or delusions. These symptoms must last at least two weeks. Some individuals have MDD once during their lifetimes, whereas most individuals with MDD have recurrent depressive episodes. Of note, developing depression after the death of a loved one is considered normal, so mental health professionals do not consider it a disorder unless the symptoms last longer than two months or severe symptoms arise, such as suicidal ideation or hallucinations.
Dysthymic disorder is another depressive disorder and shares the symptoms of major depressive disorder. However, the symptoms are milder, fewer in number and last longer (for at least two years).
Bipolar Disorders
Bipolar disorder is characterized by alternating depression and mania. In other words, individuals experience a cycle of highs and lows in their mood. During times of depression, they have symptoms of major depressive disorder. When they are manic, individuals experience extreme elation or euphoria. They may also have grandiose ideas, require little sleep, have rapid speech or thoughts or are hyperactive. Individuals experiencing at least four manic or depressive episodes within a year are considered to have rapid-cycling. DSM criteria require that manic symptoms last for at least one week or are severe enough to warrant hospitalization. Hypomania is a less severe form of mania in that the symptoms last at least four days.
Cyclothymic disorder parallels dysthymic disorder in that it is a milder but more chronic form of bipolar disorder. Individuals with cyclothymia experience alterations between mild mania (hypomania) and depressive symptoms that last for at least two years.
Prevalence of Depression and Bipolar
Major depressive disorder is more common than bipolar disorder. In a given year, about 14.8 million American adults (about 6.7 percent of American adults) had major depressive disorder, and about 5.7 million (1.5 percent) had bipolar disorder. Women are twice as likely than men to have major depressive disorder, but bipolar disorder is found at similar rates in women and men.
References
- "Archives of General Psychiatry"; Prevalence, severity, and comorbidity of twelve-month DSM-IV disorders in the National Comorbidity Survey Replication (NCS-R); Ronald Kessler, Patricia Berglund, Olga Demler, Robert Jin, Kathleen Merikangas, and Ellen Walters; June 2005.
- "Diagnostic and Statistical Manual of Mental Disorders (4th ed. Text Revision)"; American Psychiatric Association; 2002.
