'Cool' and 'Hot' executive functions in suicide attempters with major depressive disorder

Abstract

Rationale: The World Health Organization reports that, by 2030, depression is expected to be the largest contributor to disease burden. Only small proportion of patients with major depressive disorder (MDD) achieves remission and the majority of them do not achieve long-term functional recovery. One of the neuropsychological domains that have been shown to be particularly impaired in depression, is that of executive function (EF).

Objectives: We examined whether the patients with MDD with and without suicide attempts had deteriorated 'cool' EF and 'hot' EF.

Methods: The study population comprised 34 MDD attempters, 36 MDD non-attempters, and 55 healthy controls. We adopted the symmetry span task (SSPAN) to measure the updating and the affective shifting task (AST) to measure the inhibition and set-shifting in general and in response to emotional material. The Iowa gambling task (IGT) was used to examine the affective decision-making ability.

Results: After controlling for PHQ-9, Anxiety (HADS), suicidal ideation, education year and gender, we reported that (1) the MDD non-attempters had worse updating than the healthy controls and the MDD attempters; (2) the MDD attempters had worse general inhibition (GI) than the healthy controls and the MDD non-attempters; (3) the MDD non-attempters had worse general set-shifting (GS) than the healthy controls and the MDD attempters; (4) there was no between-group difference in the 'hot' EFs; and (5) MDD attempters with longer durations (over 5 years) since last attempt had worse general inhibition.

Conclusions: The disrupted 'cool' EFs patients with MDD are consistent with previous review and meta-analytic studies. On the other hand, the two groups with MDD performed similarly to the healthy controls in the 'hot' EF.

Keywords: Decision-making; Inhibition; MDD; Set-shifting; Suicide; Updating.