Purpose: Mixed features in a major depressive episode (MDE) predict bipolar disorder (BD). The mixed features specifier included in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) could be restrictive because it excludes the symptoms common to both mania/hypomania and depression, including psychomotor agitation. On the other hand, an anxious distress (ANXD) specifier has also been introduced in the DSM-5, and psychomotor agitation has been defined as a severity of ANXD. In this study, we retrospectively investigated the association between presence of ANXD in an MDE and bipolarity.
Patients and methods: The subjects were patients admitted with an MDE to the Department of Psychiatry at Tokyo Women's Medical University Hospital from December 2014 to March 2016. Eligible patients were older than 20 years of age and met the DSM-5 criteria for major depressive disorder or BD. All data were extracted from medical records. The subjects were grouped according to whether they did or did not have ANXD. The demographics and clinical features of these groups were compared. Severity of illness was evaluated according to the Hamilton Rating Scale for Depression (HRSD) score on admission.
Results: ANXD was present in 31 and absent in 33 of 64 patients with MDE. The HRSD score was significantly higher in the group with ANXD than in the group without ANXD (P=0.0041). Mixed features (P=0.0050) and suicide attempts (P=0.0206) were significantly more common in the group with ANXD than in the group without ANXD.
Conclusion: We found that the presence of ANXD in an MDE was associated with greater severity and more mixed features and suicide attempts. It is important to evaluate a patient with an MDE for ANXD so that a diagnosis of mixed depression is not missed. More studies in larger samples are needed to investigate further the association between ANXD in MDE and bipolarity.
Keywords: anxious distress; bipolarity; major depressive episode; mixed features.