Executive Dysfunction as Risk for Depression
thesisposted on 01.08.2019, 00:00 by Huiting Liu
Major Depressive Disorder (MDD) is a common and costly illness, with only moderately efficacious treatments available. Identifying risk and potential pathways for the development of MDD can help better inform treatment and prevention efforts. One common deficit in MDD is executive dysfunction; however, few studies have examined whether deficits in executive function (EF) connote risk for MDD. The present study aimed to examine whether 1) EF is poorer among individuals with current MDD and individuals with remitted MDD, compared to depression-free controls, 2) indices of EF are positively correlated within sibling pairs, and 3) family history of MDD is associated with worse performance on EF. In a sample of 402 individuals, we assessed current and lifetime MDD, family history of MDD, and measured two components of EF: set shifting and inhibition, using four subtests from a standardized battery of EF (Delis-Kaplan Executive Function System; DKEFS). Results demonstrated that set shifting deficits were present in both the acute stage of depression as well as in remission from the disease. Set shifting abilities were also significantly associated within sibling pairs, suggesting that these abilities are familial in nature. However, family history of MDD was not associated with worse performance on set shifting or inhibition. This finding may be contributable to incomplete family psychiatric data and potential false negatives in families without a history of MDD. Additionally, inhibition deficits were not present in current MDD, potentially suggesting specificity in the EF deficits in MDD. Taken together, these results lend some support to our hypothesis that set shifting may be a potential vulnerability marker for depression.