By Eleanor McDermid, Senior medwireNews Reporter
People who fall into the DSM-5 Other Specified Bipolar and Related Disorders (OSBARD) category carry a significant clinical burden, a study shows.
The OSBARD category contains: major depressive episodes with brief hypomanic episodes (2–3 days) or insufficient number of hypomanic symptoms; hypomanic episode with no prior major depressive episode; and short-duration cyclothymia (lasting less than 24 months).
Sylfa Fassassi (CHUV, Lausanne, Switzerland) and colleagues found that people with these disorders had a significantly increased rate of psychiatric comorbidities, a higher suicide rate and poorer functioning than unaffected people.
“[O]ur data support the position of these disorders within the bipolar spectrum”, write the researchers in the Journal of Affective Disorders.
The overall lifetime rate of OSBARD conditions was 1.1% among 3719 randomly selected people from the general population who underwent the semi-structured Diagnostic Interview for Genetic Studies. Specifically, 0.3% had hypomania without depression, 0.2% depression with brief hypomania and 0.5% depression plus hypomania with insufficient symptoms.
The presence of the OSBARD category made little difference to rates of bipolar I and II disorder, which had a lifetime occurrence of 1.0% and 0.8%, similar to that in other studies.
People who fell into the OSBARD category were distinct from patients with major depressive disorder (MDD). Both groups had elevated rates of psychiatric comorbidities relative to unaffected people, but OSBARD patients had notably higher rates of generalised anxiety disorder (8.1 vs 3.5%), post-traumatic stress disorder (13.5 vs 7.9%), substance use disorders (29.7 vs 16.1%) and impulse control disorder (16.2 vs 7.1%).
They also had a higher rate of suicide attempts (13.5 vs 9.4%) and poorer lifetime, worst and current functioning. This “clearly supports the separation of OSBARD from MDD”, say Fassassi and team.
By contrast, they say that the distinct position of OSBARD relative to bipolar II disorder is “questionable”, because people meeting criteria for these categories had very similar clinical characteristics. However, they stress that the similarities mean that people meeting the OSBARD criteria “are likely to deserve similar clinical attention” to patients with bipolar II disorder.
In addition, 3.0% of the cohort had a hyperthymic personality. However, this was associated with a “very mild clinical burden.” The researchers suggest that the trend towards more frequent comorbidities in this group, rather than hyperthymic personality per se, may account for the slightly increased clinical burden.
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