Depression diagnosis was not related to processing speed, according to a recent study, however, depression symptom burden was, suggesting that how one defines depression matters when evaluating slowed processing speed in depressed individuals. Participants (n=223) were research volunteers who served in the US military since September 11, 2001, and denied a history of significant brain injuries. Depression was measured using a structured interview, the Personality Assessment Inventory (PAI), and the Beck Depression Inventory-II (BDI-II). Researchers found:
- There was not a consistent pattern of slowed processing speed in those with current depressive diagnoses compared to those without.
- However, depression symptom burden per the PAI Depression scale was significant for 7 of 10 processing speed tests.
- Only non-dominant fine motor dexterity was significantly slower in those with high vs low burden using BDI-II quartiles.
- Thus, the motor slowing hypothesis was supported, but only for depression burden and not diagnostic status or high vs low categorical classification.
Shura RD, Rowland JA, Martindale SL, Brearly TW, Delahanty MB, Miskey HM. Evaluating the motor slowing hypothesis of depression. [Published online ahead of print January 27, 2017]. Psychiatry Res. doi:10.1016/j.psychres.2017.01.074.