The impact of depression heterogeneity on inhibitory control

Major depressive disorder (MDD) is associated with deficits in executive cognitive function, including inhibitory control. However, inconsistencies have been found across studies. Depression is a heterogeneous disorder and these inconsistencies may therefore relate to heterogeneity in relatively small samples.

Here we sought to examine event-related potentials (ERPs) during a cognitive Go/No-Go task in melancholic (n = 60) and non-melancholic depressed patients (n = 54) relative to controls (n = 114).

Behavioural responses indicate that inhibitory control processes are differentially affected by subtypes of depression such that melancholic patients exhibit a greater number of commission errors and more variable response rates in comparison to non-melancholic patients and controls respectively. However, ERPs do not differ during a cognitive Go/No-Go task when ERPs associated with correct responses are examined.

These findings indicate that while patients with melancholia differ from patients without melancholia and controls, no neurophysiological differences are observed when controlling for observable behavioural impairment.