Testing the efficacy of INtegral Cognitive REMediation (INCREM) in major depressive disorder: study protocol for a randomized clinical trial

Targeting disrupted rich-club network organization with neuroplasticity-based computerized cognitive remediation in major depressive disorder patients

Disrupted rich-club organization has been extensively studied in major depressive disorder (MDD) patients. Although data indicate that neuroplasticity-based computerized cognitive remediation (nCCR) can accelerate clinical responses in MDD patients, the mechanisms underlying its antidepressant efficacy are unknown. In this study, all MDD patients underwent two (baseline and week 4) neuropsychological assessments and DTI imaging. Additionally, 17 MDD patients did nCCR for 30 hours spread across 4 weeks. Rich-club organization was calculated with a graph-theoretical approach, and SC-FC coupling was explored. After 4 weeks of treatment, the number of rich-club connections, global efficiency, and SC-FC coupling strength increased significantly and were negatively associated with TMT-B scores. The effects of nCCR on disrupted rich-club organization may partly underlie its efficacy in improving the executive function of patients with MDD. Effects of nCCR on disrupted rich-club organization may partly underlie its efficacy in improving the executive function of patients with MDD.

In pursuit of full recovery in major depressive disorder

Many individuals with major depression disorder (MDD) who achieve remission of depressive symptoms, do not perceive themselves as fully recovered. This study explores whether clinical remission is related to functional remission and to patient's perception of recovery, as well as, which factors are associated with their functional and subjective remission. 148 patients with MDD in partial clinical remission were included. Demographics and clinical variables were collected through semi-structured interviews. Objective cognition was evaluated through a neuropsychological battery and subjective cognition through a specific questionnaire. The patient's psychosocial functioning and the perception of their remission were also assessed. Apart from descriptive analysis, Pearson correlations and backward stepwise regression models explored the relationship between demographic, clinical, and cognitive factors with patients' functional and self-perceived remission. From the whole sample, 57 patients (38.5%) were considered to achieve full clinical remission, 38 patients (25.7%) showed functional remission, and 55 patients (37.2%) perceived themselves as remitted. Depressive symptoms and objective and subjective executive function were the factors associated with psychosocial functioning. Besides, depressive symptoms, objective and subjective attention, and subjective executive function were the significant explanatory variables for self-perception of remission. The concept of full recovery from an episode of MDD should not only include the clinician's perspective but also the patient's psychosocial functioning along with their self-perceived remission. As residual depressive symptoms and cognition (objective and subjective) are factors with great contribution to a full recovery, clinicians should specifically address them when choosing therapeutic strategies.

Randomized clinical trial of integral cognitive remediation program for major depression (INCREM)

BACKGROUND

Despite achieving clinical remission, patients with depression encounter difficulties to return to their premorbid psychosocial functioning. Cognitive dysfunction has been proposed to be a primary mediator of functional impairment. Therefore, the new non-pharmacological procognitive strategy INtegral Cognitive REMediation for Depression (INCREM) has been developed with the aim of targeting cognitive and psychosocial functioning.

METHODS

This is a single-blind randomized controlled clinical trial with three treatment arms. Fifty-two depressed patients in clinical remission, with psychosocial difficulties and cognitive impairment, were randomly assigned to receive INCREM intervention, Psychoeducation programme, or treatment as usual. Patients were assessed before and after the study period, and six months after. The primary outcome was the change from baseline of patients' psychosocial functioning. Changes in cognitive functioning and other variables were considered secondary outcomes.

RESULTS

The analysis showed a significant improvement in psychosocial functioning in the INCREM group, especially six months after the intervention, compared to patients who received the psychoeducation programme. An improvement in cognitive performance was also observed in the INCREM group.

LIMITATIONS

This study includes a small sample size due to the anticipated end of the clinical trial because of the COVID-19 pandemic.

DISCUSSION

These results provide preliminary evidence on the feasibility and potential efficacy of the INCREM program to improve not only cognitive performance but also psychosocial functioning in clinically remitted depressed patients, and such improvement is maintained six months after. It can be speculated that the maintenance is mediated by the cognitive enhancement achieved with INCREM.