Alopecia areata bidirectionally linked to major depressive disorder

A bidirectional association exists between alopecia areata (AA) and major depressive disorder (MDD) among probands and unaffected siblings, reveals a study. This suggests that shared familial mechanisms tend to cause AA and MDD.

This study recruited participants from the National Health Insurance Research Database in Taiwan. A total of 2,123 probands with AA, 2,298 unaffected siblings and 9,192 matched controls were included to examine the risk of MDD. To assess the risk of AA, the authors included 16,543 probands with MDD, 17,352 unaffected siblings and 69,408 matched controls. The adjusted relative risk was calculated using the Breslow-Cox model.

The unadjusted relative risks for MDD were 8.22 (95 percent confidence interval [CI], 6.41–10.54) with AA probands and 2.55 (95 percent CI, 1.91–3.40) with unaffected siblings compared with matched controls. For AA, the unadjusted relative risks were 1.66 (95 percent CI, 1.24–2.22) with MDD probands and 1.64 (95 percent CI, 1.27–2.12) with unaffected siblings.

These findings are consistent with those of a recent study, which found that while patients with AA were at risk for developing MDD, having MDD also increased the risk for developing AA. [JAMA Dermatol 2019;155:475-479]

The current study, however, had certain limitations. Chief of which was the lack of data from the National Health Insurance Research Database on disease severity, body mass index, smoking habits, alcohol consumption and stressful life events.

“AA has long been associated with MDD,” according to the authors. “However, most evidence to date has derived from cross-sectional or case-control studies.”