Epidemiology

The lifetime prevalence of dysthymia has been reported in one study as about 2% in men and about 4% in women.[4] Another study reported lifetime prevalence of about 6%, with women more frequently affected than men.[5] The US National Comorbidity Replication Study reported 12-month prevalence of dysthymic disorder of 1.5%, and lifetime prevalence of 2.5% of the general population.[6][7]

Of the 4 subtypes of persistent depressive disorder, it appears that chronic major depressive disorder (MDD) may be more common than dysthymia. A study using the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) epidemiological database determined that 12-month and lifetime prevalence of chronic MDD (1.5% and 3.0%, respectively) were greater than for dysthymia (0.5% and 0.9%, respectively).[8] Similarly, a study on the lifetime prevalence of DSM-5 depressive disorders in an urban area reported a lifetime prevalence of 15.2% for PDD with persistent major depressive episode and 3.3% for PDD with pure dysthymia.[9]

Most patients have an early onset of chronic depression. A middle age-onset form has also been proposed.[10] Cerebrovascular disease appears to play a role in the aetiology of late onset depressive disorder.[10] Individuals with geriatric-age onset of chronic depression may suffer from vascular depression.[11] In one study, later age of depression onset was associated with worse outcomes, including greater risk of developing persistent depressive disorder, recurrent major depression, and functional impairment. The outcomes were worst for people aged 70 years or older, compared to the reference group of people aged 18 to 29 years at depression onset.[12]

Most people with persistent depressive disorder have comorbid psychiatric conditions, such as anxiety disorders and substance misuse. About 80% of people with persistent depressive disorder will at some point experience major depressive episodes, which may be recurrent ('double depression').[13][14][15][16] Chronic forms of depression account for about 30% of all unipolar mood disorders.[17] There is considerable psychosocial morbidity and excessive healthcare use associated with persistent depressive disorder.[18][19][20][21][22][23]

Use of this content is subject to our disclaimer