Paper in The Australian and New Zealand Journal of Psychiatry
  • Quinn, C. R., Harris, A., & Kemp, A. (2012). The impact of depression heterogeneity on inhibitory control. The Australian and New Zealand Journal of Psychiatry, doi:10.1177/0004867411432073.

    Objective: Major depressive disorder (MDD) is associated with deficits in executive cognitive function, including inhibi¬tory 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.

    Method: 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).

    Results: 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 cogni¬tive Go/No-Go task when ERPs associated with correct responses are examined.

    Conclusions: 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.