Agitated depression: a valid depression subtype?

PURPOSE

The diagnostic validity of agitated depression (AD, a major depressive episode (MDE) with psychomotor agitation) is unclear. It is not classified in DSM-IV and ICD-10 classification of mental and behavioural disorder (ICD-10). Some data support its subtyping. This study aims to test the subtyping of AD.

METHODS

Consecutive 245 bipolar-II (BP-II) and 189 major depressive disorder (MDD) non-tertiary-care MDE outpatients were interviewed (off psychoactive drugs) with Structured Clinical Interview for DSM-IV Axis I Disorders--Clinician Version (SCID-CV), Hypomania Interview Guide (HIGH-C), and Family History Screen. Intra-MDE hypomanic symptoms were systematically assessed. AD was defined as an MDE with psychomotor agitation. Mixed AD was defined as an MDE with four or more hypomanic symptoms (including agitation).

FINDINGS

AD was present in 34.7% of patients. AD was mixed in 70.1% of AD patients. AD, vs. non-AD, had significantly (at alpha = 0.05) lower age at onset, more BP-II, females, atypical depressions, bipolar-I (BP-I) and BP-II family history, and was more mixed; racing/crowded thoughts, irritability, more talkativeness, and risky behaviour were significantly more common. Mixed AD, vs. non-AD, had significantly (at alpha = 0.01) lower age at onset, more intra-MDE hypomanic symptoms, BP-II, females, atypical depressions, BP-II family history, and specific hypomanic symptoms (distractibility, racing thoughts, irritable mood, more talkativeness, risky activities). Mixed AD, vs. non-mixed AD, had significantly more intra-MDE hypomanic symptoms (by definition), more recurrences, and more specific hypomanic symptoms (by definition). Non-mixed AD, vs. non-AD, had significantly more intra-MDE hypomanic symptoms and more talkativeness.

CONCLUSIONS

AD was common in non-tertiary-care depression outpatients, supporting its diagnostic utility. AD and many bipolar diagnostic validators were associated, supporting its link with the bipolar spectrum. Mixed AD, but not non-mixed AD, had differences vs. non-AD similar to those of AD, suggesting that psychomotor agitation by itself may not be enough to identify AD as a subtype. Findings seem to support the subtyping of mixed AD. This subtyping may have important treatment impact, as antidepressants alone might increase agitation.