Subthreshold hypomania is associated with a significantly increased risk for lifetime suicide attempts among those with major depressive disorder, according to a study recently published in the Journal of Affective Disorders. Subthreshold hypomania was also associated with a diagnosis of posttraumatic stress disorder (PTSD).

The researchers used data from face-to-face interviews with 12,526 adults who each came from a different household. The Korean Composite International Diagnostic Interview was used to assess depression, and a questionnaire was used to collect information on lifetime suicide attempts. To compare variables between groups, the χ2 test was utilized. The Student t-test was used to compare those having major depressive disorder with and without subthreshold hypomania, as well as those not having major depressive disorder with and without subthreshold hypomania.

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Among interviewees, 825 had major depressive disorder, and 11,701 had no major depressive disorder diagnosis. There were 72 (8.73%) participants with major depressive disorder and subthreshold hypomania. This subgroup had significantly higher PTSD (18.1% vs 9.0%; P =.014) and lifetime suicide attempts (28.6% vs 16.1%; P =.008) than the 753 participants with major depressive disorder and no subthreshold hypomania, and its individuals were significantly younger (38.9±11.9 years vs 45.5±14.3 years; P =.0001). The group without major depressive disorder and with subthreshold hypomania (n=130) had higher lifetime suicide attempts and rates of comorbidities than did the group without major depressive disorder or subthreshold hypomania (n=11,571). Those with major depressive disorder were 8.30 times likelier (95% confidence interval [CI], 6.67-10.33) to have a lifetime suicide attempt (P <.001) compared with those without major depressive disorder. The lifetime suicide attempt risk for those with subthreshold hypomania vs no subthreshold hypomania was 8.55 times higher (95% CI, 5.96-12.26; P <.001). The group with major depressive disorder and subthreshold hypomania was 2.08 (95% CI, 1.20-3.62; P <.001) times likelier to have a lifetime suicide attempt than those with major depressive disorder without subthreshold hypomania.

Limitations to this study include a cross-sectional design, the potential for recall bias, possible underrepresentation of major depressive disorder and bipolar disorder, potential false negatives on the questionnaires, the potential psychiatric implications of nonresponders to the questionnaire, and the use of only Korean participants, which may make it difficult to generalize the results to other ethnicities.

The study researchers conclude that “a lifetime history of subthreshold hypomania was associated with suicide attempts in community populations with [major depressive disorder]. In comparison with the [major depressive disorder] without subthreshold hypomania group, the [major depressive disorder] with subthreshold hypomania group were more likely to have a PTSD diagnosis, and more frequent morning worsening of mood. This study indicated that community populations with [major depressive disorder] should be carefully monitored if they have a history of subthreshold hypomania because individuals with [major depressive disorder] and a history [of] subthreshold hypomania may be at greater risk for suicide attempts, and for past PTSD experiences.”

Reference

Choi KW, Na EJ, Hong JP, et al. Comparison of suicide attempts in individuals with major depressive disorder with and without history of subthreshold hypomania: a nationwide community sample of Korean adults [published online January 26, 2019]. J Affect Disord. doi: 10.1016/j.jad.2019.01.022