Baseline predictors of cognitive change in the treatment of major depressive episode: systematic review

Change in Cognitive Function over the Course of Major Depressive Disorder: A Systematic Review and Meta-analysis

Major depressive disorder (MDD) is associated with significant cognitive deficits during the acute and remitted stages. The aim of this systematic review and meta-analysis was to examine the course of cognitive function whilst considering demographic, treatment, or clinical features of MDD that could moderate the extent of cognitive change. Databases were searched to identify studies that reported on cognitive function in MDD with a ≥12-week test-retest interval. Relevant studies were pooled using random effects modelling to generate an inverse-variance, weighted, mean effect size estimate (Hedges' g) of cognitive change for each cognitive variable and for an overall composite cognitive domain. Of 6898 records, 99 eligible studies were identified from which 69 were meta-analysed, consisting of 4639 MDD patients (agemean = 40.25 years, female% = 64.62%) across 44 cognitive variables. In over 95% of cognitive variables, improvements were either of non-significant, negligible, or of a small magnitude, and when compared to matched healthy controls, the possibility of practice effects could not be precluded. Depressive symptom improvement and the number of previous depressive episodes moderated the extent of cognitive change, demonstrating state- and scar-like features for one-quarter of the cognitive domains. Further longitudinal studies are required to elucidate the MDD cognitive trajectory from initial onset. Findings nonetheless suggest that following pharmacological and non-pharmacological treatment, cognitive change in MDD is typically small, but the capacity for change may be less with episode recurrence. Targeting cognition early in the course of illness may facilitate better prognosis and support a more complete functional recovery.

Enhanced External Counterpulsation Improves Cognitive Function of Persons With Long COVID

OBJECTIVE

The aim of this study is to determine the effects of enhanced external counterpulsation (EECP) in patients with long COVID and objectively assessed cognitive impairment.

DESIGN

A retrospective evaluation of long COVID patients referred for EECP, with cognitive sequela, and having completed an objective digital assessment before and after therapy. Patients had either cognitive impairment or no cognitive impairment at baseline. We assessed changes in composite score using multifactor analysis of variance. Multiple linear and logistic regression analyses were conducted to evaluate several independent variables.

RESULTS

Eighty long COVID patients (38 cognitive impairment vs. 42 no cognitive impairment) were included for analyses. All baseline characteristics were well matched. There was significant improvement in composite score post EECP in those with objective cognitive impairment at baseline. There were no notable documented safety concerns.

CONCLUSIONS

This is the first study showing that EECP led to significant improvement in cognitive functioning of long COVID patients with objectively defined cognitive impairment. Although a lack of a negative control group is a limitation of this study, EECP seems to be highly safe and effective with the potential for widespread application.

Randomised controlled trial of Interpersonal and Social Rhythm Therapy and group-based Cognitive Remediation versus Interpersonal and Social Rhythm Therapy alone for mood disorders: study protocol

BACKGROUND

Individuals with mood disorders frequently experience cognitive impairment, which impacts on the long-term trajectory of the disorders, including being associated with persisting difficulties in occupational and psychosocial functioning, residual mood symptoms, and relapse. Current first-line treatments for mood disorders do little to improve cognitive function. Targeting cognition in clinical research is thus considered a priority. This protocol outlines a prospectively-registered randomised controlled trial (RCT) which examines the impact of adding group-based Cognitive Remediation (CR) to Interpersonal and Social Rhythm Therapy (IPSRT-CR) for individuals with mood disorders.

METHODS

This is a pragmatic, two-arm, single-blinded RCT comparing IPSRT-CR with IPSRT alone for adults (n = 100) with mood disorders (Major Depressive Disorder or Bipolar Disorder) with subjective cognitive difficulties, on discharge from Specialist Mental Health Services in Christchurch, New Zealand. Both treatment arms will receive a 12-month course of individual IPSRT (full dose = 24 sessions). At 6 months, randomisation to receive, or not, an 8-week group-based CR programme (Action-based Cognitive Remediation - New Zealand) will occur. The primary outcome will be change in Global Cognition between 6 and 12 months (treatment-end) in IPSRT-CR versus IPSRT alone. Secondary outcomes will be change in cognitive, functional, and mood outcomes at 6, 12, 18, and 24 months from baseline and exploratory outcomes include change in quality of life, medication adherence, rumination, and inflammatory markers between treatment arms. Outcome analyses will use an intention-to-treat approach. Sub-group analyses will assess the impact of baseline features on CR treatment response. Participants' experiences of their mood disorder, including treatment, will be examined using qualitative analysis.

DISCUSSION

This will be the first RCT to combine group-based CR with an evidence-based psychotherapy for adults with mood disorders. The trial may provide valuable information regarding how we can help promote long-term recovery from mood disorders. Many issues have been considered in developing this protocol, including: recruitment of the spectrum of mood disorders, screening for cognitive impairment, dose and timing of the CR intervention, choice of comparator treatment, and choice of outcome measures.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry, ACTRN12619001080112 . Registered on 6 August 2019.

Prediction of residual cognitive disturbances by early response of depressive symptoms to antidepressant treatments in patients with major depressive disorder

BACKGROUND

Patients with major depressive disorder (MDD) frequently retain cognitive disturbances after recovery from mood symptoms. We investigated the relationship between early response of mood symptoms and/or remission, and residual cognitive disturbances after 6 months of antidepressant treatment.

METHODS

518 patients with MDD were followed up for 6 months after antidepressant treatment initiation (first-line or switch from a previous drug). Subjective and objective cognitive disturbances were assessed by the Perceived Deficits Questionnaire - Depression (PDQ-D) and digit symbol substitution test (DSST), respectively. Depressive symptoms, as well as remission and early response to treatment, were assessed using the Montgomery-Asberg Depression Rating Scale (MADRS). Multivariable linear and logistic regression models were used to adjust for confounders.

RESULTS

Early response of depressive mood (≥50% reduction in MADRS score at month 1) was related with fewer residual subjective cognitive symptoms, as evaluated by the PDQ-D at month 6 (p<0.001). Likewise, early remission status at month 2 was inversely associated with PDQ-D scores at month 6 (p<0.001). Among patients with baseline DSST scores of ≥1 standard deviation below the norm, early response/remission was associated with better performance on the DSST at month 6 (p<0.05).

LIMITATIONS

The cohort may not be representative of the general MDD patient population, and the possible influence of concomitant medications was not evaluated.

CONCLUSIONS

These findings suggest that early improvements in depressive symptoms predict better cognitive outcomes in patients with MDD. Grouping of patients by mood and cognition status in early stages of antidepressant treatments may facilitate efforts to improve long-term functional outcomes.

Systematic review of the effects of evidence-based psychotherapies on neurocognitive functioning in mood disorders

OBJECTIVE

Neurocognitive impairment is considered a core feature of mood disorders. Research has shown that neurocognitive impairment often persists beyond mood symptom resolution and can have significant deleterious effects on interpersonal relationships, academic achievement, occupational functioning and independent living. As such, neurocognitive impairment has become an important target for intervention. In this systematic review, we aimed to examine the extant literature to ascertain whether current standard evidence-based psychotherapies can improve neurocognitive functioning in mood disorders.

METHOD

Studies examining changes in neurocognitive functioning following evidence-based psychotherapy were identified using MEDLINE, PsycINFO and Web of Science databases. Given the heterogeneity of study procedures, treatment protocols and patient samples, a narrative rather than meta-analytic review technique was employed.

RESULTS

Nineteen studies (21 articles) met inclusion criteria. There was preliminary evidence of improved executive functioning following evidence-based psychotherapy for Major Depressive Disorder and Bipolar Disorder. There was also some signal of reduced negative biases in emotional information processing following psychotherapy in depression. Due to methodological variability across studies however, it was difficult to draw clear conclusions.

CONCLUSION

Findings from the current review suggest that evidence-based psychotherapies may influence some aspects of neurocognitive functioning in mood disorders. This continues to be an ongoing area of importance and warrants further research.

The effect of selective serotonin reuptake inhibitors on cognitive impairment in patients with depression: A prospective, multicenter, observational study

Whether selective serotonin reuptake inhibitors (SSRIs) can improve cognitive function in depressed patients remains unclear. We aimed to explore the effect of SSRIs on cognitive function and the influencing factors in patients with major depressive disorder (MDD) with impaired cognitive function. We used a neurocognitive test battery to assess five cognitive domains, namely, attention/vigilance, learning, memory, processing speed and executive functioning, and calculated the Global Deficit Score (GDS). A GDS≥0.5 indicated overall cognitive impairment. The changes in the cognitive domains and overall cognitive function were analyzed in MDD patients with a baseline GDS≥0.5 who completed 8 weeks of SSRI treatment. We divided the patients into the cognitive remission and nonremission groups to explore the associated factors. In total, 160 patients (mean age 37.6 ± 10.8 years, 30.6% male) were included in the final analysis. The median (quartiles) of baseline GDS and HRSD17 were 1.4 (0.8, 1.9) and 19.5 (17.0, 23.0), respectively. All five cognitive domains improved after the treatment, while only 41 (25.6%) patients achieved cognitive remission. Recurrence and a higher baseline GDS were risk factors for cognitive nonremission. More aggressive interventions may be needed to promote cognitive remission in clinical practice, especially for patients with severe cognitive impairment and recurrent episodes.

Cognition in mood disorders

Cognitive impairment plays a key role in determining the course of illness and functional outcomes in mood disorders. This article summarises and discusses important papers within this thematic series of BJPsych Open that contribute to a greater understanding of the complexity of 'Cognition in Mood Disorders'.