Set Shifting and Inhibition Deficits as Potential Endophenotypes for Depression

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• The causes of Major Depressive Disorder (MDD) remain unclear, necessitating the identification of intermediate phenotypes (endophenotypes) to aid treatment and prevention.
• Cognitive impairments, specifically in set-shifting and inhibition, are frequently observed in MDD but require further investigation as potential endophenotypes.

Purpose of the Study:

• To determine if set-shifting and inhibition meet endophenotype criteria for MDD.
• To assess if these cognitive functions are impaired in individuals with current MDD and remitted MDD.
• To examine the familiality of set-shifting and inhibition deficits within sibling pairs.

Main Methods:

• Utilized Delis-Kaplan Executive Function System subtests to measure set-shifting and inhibition.
• Employed the Structured Clinical Interview for DSM-5 to assess psychopathology.
• Analyzed data for impairments in current MDD, remitted MDD, and familial correlations.

Main Results:

• Set-shifting deficits were found to be familial and present in both current and remitted MDD groups, suggesting state-independent characteristics.
• Inhibition deficits were familial but showed limited impairment in current or remitted MDD groups.
• Remitted MDD individuals without current disorders demonstrated impairments in one of two inhibition tasks.

Conclusions:

• Impaired set-shifting emerges as a strong candidate for an MDD endophenotype.
• Inhibition may not serve as a robust endophenotype for MDD.
• Further research is needed to confirm generalizability across populations and explore longitudinal associations.