Executive function in treatment-resistant depression before and after electroconvulsive therapy

The aim of this study was to examine executive functions (EF) in patients with treatment-resistant depression (TRD) before and after bitemporal electroconvulsive therapy (ECT) and to evaluate possible associations between the depression severity and executive tasks performances.

Patients (n = 29), treated with bitemporal ECT, underwent assessment at three time points: baseline, immediately after ECT course and 1 month later. The Stockings of Cambridge (SOC, CANTAB) was used to assess EF: (1) number of problems solved in minimum moves (SOC-P), (2) initial thinking time (SOC-I) and (3) subsequent thinking time (SOC-T).

The scores on the Hamilton Depression Rating Scale and the Clinical Global Impression scale were significantly reduced over time, with no negative effects on the EF. Among SOC subtests, only SOC-I improved over time, which was significantly correlated with the depressive symptoms reduction. SOC-T and SOC-P remained unchanged and did not correlate with mood. Interestingly, the patients with more lifetime psychiatric hospitalisations and more ECT applications were more likely to drop-out and to have longer SOC-T while performing the test.

Our results support the view that ECT does not produce long-lasting EF deficits, nor exacerbates the pre-existing ones. The improvement of the EF performances during and after the ECT-induced alleviation of mood symptoms in TRD is based mostly on the reduction of time needed to plan the problem solution.