Background: The relationship between major depressive disorder (MDD) and personality disorders is complex, with implications for diagnosis and treatment. We sought to explore the relationship between these disorders quantitatively in an inpatient setting.
Methods: We conducted a structured observational study exploring symptoms of depression and selected neurocognitive functions over the span of an inpatient admission in those with depression and personality disorders. Sixty inpatients presenting with symptoms of depression completed ratings of mood and neurocognitive function. Diagnosis was confirmed by structured clinical interview (SCID-5-RV) at discharge and used to allocate patients to one of the two groups for analysis: those with MDD-only and those with a personality disorder (with or without MDD).
Results: On admission, observer-based ratings of depression were significantly higher in the MDD-only group while subjective ratings were higher in the personality disorder group. Depression rating scores lessened in both groups during the admission, but at discharge, the personality disorder group continued to report higher subjective ratings. The personality disorder group also rated themselves as more cognitively impaired than the MDD-only group and unlike the MDD-only group, they did not report subjective improvements in cognitive function over the course of admission. Objective assessment of cognitive function demonstrated improvements in both groups.
Conclusions: In this study, the presence of a personality disorder was associated with greater subjective severity of depressive symptomatology and selected neurocognitive functioning, despite similar or lower objective severity in comparison with those with MDD. This finding has implications for understanding the patient journey through health care settings.
Keywords: Major depressive disorder; neurocognition; personality disorder.