The specificity of neuropsychological impairment in predicting antidepressant non-response in the very old depressed

Aripiprazole as First-Line Therapy for Late-Life Depression: A Case Note Review

BACKGROUND

Aripiprazole, structurally considered a third-generation antipsychotic agent, is an effective adjuvant strategy for managing treatment-resistant depression. It has been used successfully as an add-on agent in late-life depression (LLD), but there are no controlled trials on its use as first-line therapy, either alone or in combination with an antidepressant.

METHODS

This is a case note review of aripiprazole prescribed to outpatients with LLD as a first-line therapy either in combination with an antidepressant or as a monotherapy. The local ethics committee approved the audit. Case notes of subjects with Hamilton Rating Scale for Depression scores of ≥11 and with at least 1 follow-up visit were included in the review. Remission was defined as the first occurrence of achieving a Hamilton Rating Scale for Depression score of <10.

RESULTS

Case notes of 54 subjects (mean age, 68.6 ± 6.9 years) were included, 52 of whom had unipolar depression. Aripiprazole alone was prescribed in 21 subjects, and with an antidepressant in the remaining subjects. The overall remission rate was 59% over 21 weeks, and in the remitted subjects (n = 32), the cumulative remission rate increased from 22% at week 2 to 82% at week 10. No subject discontinued treatment because of poor tolerability or serious adverse events.

CONCLUSIONS

Aripiprazole was found to be an effective first-line antidepressant in LLD. The remission rates in the present study were considerably higher than the published literature on antidepressant monotherapy in fresh episodes of LLD. This warrants controlled trials of aripiprazole as a first-line antidepressant for this disease entity.

Prediction of Antidepressant Efficacy by Cognitive Function in First-Episode Late-Life Depression: A Pilot Study

The response rate of treatment for late-life depression (LLD) is only 25-60%. The cognitive impairment associated with LLD often affects the effectiveness of antidepressants and may has the potential ability to predict response. This study seeks a biomarker for baseline cognitive function to predict efficacy of antidepressants. Sixty patients diagnosed with LLD received escitalopram or sertraline treatment for 8 weeks. Clinical symptom was measured using Hamilton Depression Rating Scale-17 (HAMD-17) and cognitive function was measured using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Trail Making Test (TMT) before and after 8-week treatment. Patients were divided into treatment effective group (TE) and treatment ineffective group (TI) according to reduction rate in scores of HAMD-17 after treatment. Thirty-eight matched healthy controls (HC) were assessed using RBANS and TMT. There was significant decrease of score of RBANS and increase of score of TMT in patients with LLD compared with HC. Regression analysis revealed that change in HAMD-17 score was significantly positively associated with baseline score of picture naming, figure copy, digit span, and delayed memory. The preliminary findings suggested that working memory, attention, visuospatial, language function, and delayed memory should be examined further as a means of providing the useful objective biomarkers of treatment response.

CLINICAL TRIALS REGISTRATION

[www.ClinicalTrials.gov], identifier [ChiCTR2100042370].

Targeting Cognitive Control Deficits With Neuroplasticity-Based Computerized Cognitive Remediation in Patients With Geriatric Major Depression: A Randomized, Double-Blind, Controlled Trial

Late life major depression (LLD) is often accompanied by cognitive deficits. When patients have specific deficits in cognitive control functions (CCD), they are not only distressing and debilitating, they often predict poor clinical outcomes such as reduced response to SSRI/SNRI antidepressants, increased disability, suicide and all-cause mortality. We recently reported that in an open label trial, our treatment designed to target these specific CCD with neuroplasticity-based computerized cognitive remediation (nCCR) improved depression and CCD in patients who failed to remit with conventional antidepressant treatment. This study tested the hypothesis that in patients with LLD who have failed at least one trial of an SSRI/SNRI antidepressant at an adequate dose for at least 8 weeks, nCCR will improve both depressive symptoms and the CCD associated with poor antidepressant response (i.e. semantic strategy, inhibition of prepotent responses) more than an active control group. Participants were randomized (1:1) to receive either 30 hours/ 4 weeks of neuroplasticity based computerized cognitive remediation (nCCR) designed to target CCD, or the active control condition matched for duration, engagement, reward, computer presentation, and contact with study staff. All participants and raters were blinded. Mixed effects model analysis the time effect (week) (F(1,71.22)=25.2, p<0.0001) and treatment group X time interaction (F(1,61.8)=11.37, p=.002) reached significance indicating that the slope of decline in MADRS was steeper in the nCCR-GD group. Further, the nCCR group improved their semantic clustering strategy(t(28)=9.5; p=.006), as well as performance on the Stroop interference condition, and cognitive flexibility (Trails B). Further, results transferred to memory performance, which was not a function trained by nCCR. clinicaltrials.gov.

Neurocognition in Post-Treatment Lyme Disease and Major Depressive Disorder

OBJECTIVE

Neurocognitive dysfunction in patients with residual or emergent symptoms after treatment for Lyme Disease is often attributed to comorbid depression. In this study, patients with Post-Treatment Lyme Disease Syndrome (PTLDS) were compared to patients with Major Depressive Disorder (MDD), as well as healthy comparison subjects (HC), on neurocognitive measures administered through the same laboratory, to determine if patterns of performance were similar.

METHODS

Two analyses were conducted. First, performance on the Wechsler Adult Intelligence Scale (WAIS-III) and on subtests from the Wechsler Memory Scale (WMS-III) was compared among the groups. Second, comparable subgroups of PTLDS and MDD patients with at least one low WMS-III score were compared on an additional set of measures assessing motor function, psychomotor performance, attention, memory, working memory, and language fluency, to determine if the overall profile of performance was similar in the two subgroups.

RESULTS

In the first analysis, PTLDS patients performed more poorly than both MDD and HC on tasks assessing verbal abilities, working memory, and paragraph learning. Processing speed in the two patient groups, however, was equally reduced. In the second analysis, MDD patients with low WMS-III exhibited concomitantly greater difficulties in psychomotor speed and attention, while low-WMS-III PTLDS patients exhibited greater difficulties in language fluency.

CONCLUSIONS

MDD and PTLDS can be confused neuropsychologically because both exhibit similar levels of psychomotor slowing. However, problems on memory-related tasks, though mild, are more pronounced in PTLDS. PTLDS patients with poorer memory also exhibit poorer language fluency, and less deficit in processing speed and attention compared to MDD.

Neurocognitive performance predicts treatment outcome with cognitive behavioral therapy for major depressive disorder

The current study examined the contribution of baseline neuropsychological functioning to the prediction of antidepressant outcome with cognitive behavioral therapy (CBT) for Major Depressive Disorder (MDD). We hypothesized that depressed participants who were more neurocognitively intact and had less rigid, negative thinking would respond better to CBT. Thirty-one MDD patients completed a comprehensive neuropsychological battery before initiation of CBT. A subgroup also completed a probabilistic reversal learning task. Depression severity was assessed with the Beck Depression Inventory (BDI); rigid, negative thinking was assessed with the Dysfunctional Attitudes Scale (DAS) and the Automatic Thoughts Questionnaire (ATQ) throughout treatment. Remitters were compared to non-remitters. Paradoxically, eventual remitters performed generally worse across the neuropsychological battery considered as a whole. Univariate testing showed a significant difference on only a single measure, the Continuous Performance Test d', when corrected for multiple comparisons. Baseline rigid, negative thinking did not predict treatment outcome. Results suggest that the structure of CBT may particularly benefit individuals with mild depression-related neurocognitive difficulties during a depressive episode. Further research is needed to examine these patient characteristics and their potential contribution to the mechanisms of CBT efficacy.

Predictors of treatment outcome in depression in later life: A systematic review and meta-analysis

BACKGROUND

Predictor analyses of late-life depression can be used to identify variables associated with outcomes of treatments, and hence ways of tailoring specific treatments to patients. The aim of this review was to systematically identify, review and meta-analyse predictors of outcomes of any type of treatment for late-life depression.

METHODS

Pubmed, Embase, CINAHL, Web of Science and PsycINFO were searched for studies published up to December 2016. Primary and secondary studies reported treatment predictors from randomised controlled trials of any treatment for patients with major depressive disorder aged over 60 were included. Treatment outcomes included response, remission and change in depression score.

RESULTS

Sixty-seven studies met the inclusion criteria. Of 65 identified statistically significant predictors, only 7 were reported in at least 3 studies. Of these, 5 were included in meta-analyses, and only 3 were statistically significant. Most studies were rated as being of moderate to strong quality and satisfied key quality criteria for predictor analyses.

LIMITATIONS

The searches were limited to randomised controlled trials and most of the included studies were secondary analyses.

CONCLUSIONS

Baseline depression severity, co-morbid anxiety, executive dysfunction, current episode duration, early improvement, physical illnesses and age were reported as statistically significant predictors of treatment outcomes. Only the first three were significant in meta-analyses. Subgroup analyses showed differences in predictor effect between biological and psychosocial treatment. However, high heterogeneity and small study numbers suggest a cautious interpretation of results. These predictors were associated with various mechanisms including brain pathophysiology, perceived social support and proposed distinct types of depressive disorder. Further investigation of the clinical utility of these predictors is suggested.

A Systematic Review of Cognitive Predictors of Treatment Outcome in Major Depression

Background: Research suggests that only 50% of patients with major depression respond to psychotherapy or pharmacological treatment, and relapse is common. Therefore, there is interest in elucidating factors that help predict clinical response. Cognitive impairment is a key feature of depression, which often persists beyond remission; thus, the aim of this systematic review was to determine whether baseline cognitive functioning can predict treatment outcomes in individuals with depression. Method: Studies examining cognitive predictors of treatment response in depression were identified using Pub Med and Web of Science databases. Given the heterogeneity of outcome measures, the variety of treatment protocols, and the differing ways in which data was presented and analyzed, a narrative rather than meta-analytic review technique was used. Results: 39 studies met inclusion criteria. Findings in younger adult samples were inconclusive. There was some evidence for a predictive effect of executive function and to a lesser extent, psychomotor speed, on treatment response. There was no evidence of learning or memory being associated with treatment response. In older-aged samples, the evidence was much more consistent, suggesting that poor executive function predicts poor response to SSRIs. Conclusions: Findings from the present review suggest that certain aspects of cognitive functioning, particularly executive function, may be useful in predicting treatment response in depression. This is certainly the case in elderly samples, with evidence suggesting that poor executive functioning predicts poor response to SSRIs. With further research, baseline cognitive functioning may serve as a factor which helps guide clinical decision making. Moreover, cognitive deficits may become targets for specific pharmacological or psychological treatments, with the hope of improving overall outcome.

A Meta-Analysis of Executive Dysfunction and Antidepressant Treatment Response in Late-Life Depression

OBJECTIVE

Depressed older adults with executive dysfunction (ED) may respond poorly to antidepressant treatment. ED is a multifaceted construct and different studies have measured different aspects of ED, making it unclear which aspects predict poor response. Meta-analytic methods were used to determine whether ED predicts poor antidepressant treatment response in late-life depression and to determine which domains of executive functioning are responsible for this relationship.

METHODS

A Medline search was conducted to identify regimented treatment trials contrasting executive functioning between elderly responders and nonresponders; only regimented treatment trials for depressed outpatients aged 50 and older were included. Following the most recent PRISMA guidelines, 25 measures of executive functioning were extracted from eight studies. Six domains were identified: cognitive flexibility, planning and organization, response inhibition, selective attention, verbal fluency, and the Dementia Rating Scale Initiation/Perseveration composite score (DRS I/P). Hedge's g was calculated for each measure of executive functioning. A three-level Bayesian hierarchical linear model (HLM) was used to estimate effect sizes for each domain of executive functioning.

RESULTS

The effect of planning and organization was significantly different from zero (Bayesian HLM estimate of domain effect size: 0.91; 95% CI: 0.32-1.58), whereas cognitive flexibility, response inhibition, selective attention, verbal fluency, and the DRS I/P composite score were not.

CONCLUSION

The domain of planning and organization is meaningfully associated with poor antidepressant treatment response in late-life depression. These findings suggest that therapies that focus on planning and organization may provide effective augmentation strategies for antidepressant nonresponders with late-life depression.

Cognitive control, reward-related decision making and outcomes of late-life depression treated with an antidepressant

BACKGROUND

Executive processes consist of at least two sets of functions: one concerned with cognitive control and the other with reward-related decision making. Abnormal performance in both sets occurs in late-life depression. This study tested the hypothesis that only abnormal performance in cognitive control tasks predicts poor outcomes of late-life depression treated with escitalopram.

METHOD

We studied older subjects with major depression (N = 53) and non-depressed subjects (N = 30). Executive functions were tested with the Iowa Gambling Test (IGT), Stroop Color-Word Test, Tower of London (ToL), and Dementia Rating Scale - Initiation/Perseveration domain (DRS-IP). After a 2-week placebo washout, depressed subjects received escitalopram (target daily dose: 20 mg) for 12 weeks.

RESULTS

There were no significant differences between depressed and non-depressed subjects on executive function tests. Hierarchical cluster analysis of depressed subjects identified a Cognitive Control cluster (abnormal Stroop, ToL, DRS-IP), a Reward-Related cluster (IGT), and an Executively Unimpaired cluster. Decline in depression was greater in the Executively Unimpaired (t = -2.09, df = 331, p = 0.0375) and the Reward-Related (t = -2.33, df = 331, p = 0.0202) clusters than the Cognitive Control cluster. The Executively Unimpaired cluster (t = 2.17, df = 331, p = 0.03) and the Reward-Related cluster (t = 2.03, df = 331, p = 0.0433) had a higher probability of remission than the Cognitive Control cluster.

CONCLUSIONS

Dysfunction of cognitive control functions, but not reward-related decision making, may influence the decline of symptoms and the probability of remission of late-life depression treated with escitalopram. If replicated, simple to administer cognitive control tests may be used to select depressed older patients at risk for poor outcomes to selective serotonin reuptake inhibitors who may require structured psychotherapy.

Neuroplasticity-based computerized cognitive remediation for treatment-resistant geriatric depression

Executive dysfunction (ED) in geriatric depression (GD) is common, predicts poor clinical outcomes and often persists despite remission of symptoms. Here we develop a neuroplasticity-based computerized cognitive remediation treatment (CCR-GD) to target ED in GD. Our assumption is that remediation of these deficits may modulate the underlying brain network abnormalities shared by executive dysfunction and depression. We compare CCR-GD to a gold standard treatment (escitalopram: 20mgs/12 weeks) in 11 treatment resistant older adults with major depression; and 33 matched historical controls. We find that 91% of participants complete CCR-GD. CCR-GD is equally as effective at reducing depressive symptoms as escitalopram but does so in 4 weeks instead of 12. In addition CCR-GD improves measures of executive function more than the escitalopram. We conclude that CCR-GD may be equally effective as escitalopram in treating GD. In addition, CCR-GD participants showed greater improvement in executive functions than historical controls treated with escitalopram.

Choosing treatment for depression in older adults and evaluating response

An update is provided on the current information regarding late life depression with regard to assessment, clinical implications, and treatment recommendations. Several treatments are considered evidence-based, but when deployed into field trials, the efficacy of these treatments falls short. It is thought that the lower impact in community trials is due in large part to patient, clinical, environmental, socio-economic, and cognitive correlates that influence treatment response. The aim is to assist providers in making decisions about what type of treatment to recommend based on a sound assessment of these clinical correlates.

Antidepressant treatment of melancholia in older adults

OBJECTIVE

This is the first prospective trial in an outpatient sample comparing the effect of nortriptyline with sertraline in the treatment of depression with and without melancholia. We hypothesized that patients with melancholia would respond better to nortriptyline than sertraline, whereas among patients without melancholia, nortriptyline and sertraline would have equal efficacy.

METHODS

We conducted a randomized 12-week trial comparing sertraline with nortriptyline in the treatment of patients with nonpsychotic, unipolar major depression stratified by the presence of melancholia. One hundred ten unipolar depressed patients with and without melancholia comprised our intent-to-treat sample. Seventy-two were nonmelancholic depressed and randomly assigned to treatment with sertraline (N = 40) or nortriptyline (N = 32). Thirty-eight were melancholic depressed and randomly assigned to treatment with sertraline (N = 18) or nortriptyline (N = 20).

RESULTS

The test of the interaction of medication group and melancholia status on response was not statistically significant. Among patients with melancholia, response rates were 47% to sertraline and 75% to nortriptyline, whereas among patients without melancholia, response rates were 51% to sertraline and 42% to nortriptyline. The odds of response for patients with melancholia treated with nortriptyline compared with sertraline was 3.46. The odds of response for patients without melancholia treated with sertraline compared with nortriptyline was 0.69. Similar findings were obtained in the remission and continuous outcome analyses.

CONCLUSION

This study did not find a significant difference between sertraline and nortriptyline in the treatment of depressed older adults with melancholia.

Cognitive deficits in geriatric depression: clinical correlates and implications for current and future treatment

The purpose of this article is to identify the cognitive deficits commonly associated with geriatric depression and describe their clinical significance. The complex relationship between geriatric depression and dementia is summarized and possible shared mechanisms discussed. Evidence regarding whether the cognitive deficits in depression may be mitigated with medication or with computerized cognitive remediation is presented.

The external validity of MRI-defined vascular depression

OBJECTIVE

Multiple diagnostic criteria have been used to define vascular depression (VD). As a result, there are discrepancies in the clinical characteristics that have been established for the illness. The aim of this study was twofold. First, we used empirically established diagnostic criteria to determine the clinical characteristics of magnetic resonance imaging (MRI)-defined VD. Second, we assessed the agreement between a quantitative and qualitative method for identifying the illness.

METHOD

We examined the baseline clinical and neuropsychological profile of 38 patients from a larger, double-blind, randomized, 12-week clinical trial comparing nortriptyline with sertraline in depressed older adults. Ten patients met quantitative criteria for MRI-defined VD based on the highest quartile of deep white matter hyperintensity (DWMH) volume. Fourteen patients met qualitative criteria for MRI-defined VD based on a DWMH score of 2 or higher on the Fazekas' modified Coffey rating scale.

RESULTS

Age, gender, cumulative illness rating scale-geriatric (CIRS-G) score, two measures of psychomotor retardation [the psychomotor retardation item of the Hamilton Rating Scale for Depression (HRSD) as well as performance on the Purdue Pegboard], and performance on the Stroop Color/Word test (a measure of the response inhibition component of executive functioning) were significantly different between those with VD and non-VD.

CONCLUSIONS

Patients with VD have a distinct clinical and neuropsychological profile that is mostly consistent across different methods for identifying the illness. These findings support the notion that MRI-defined VD represents a unique and valid subtype of late-life depression.

Neuroplasticity-based computerized cognitive remediation for geriatric depression

OBJECTIVE

This article describes a novel treatment model designed to target specific neurocognitive deficits in geriatric depression with neuroplasticity-based computerized cognitive remediation (NBCCR).

METHOD

The recent National Institute of Mental Health (NIMH) report "From Discovery to Cure" calls for studies focusing on mechanisms of treatment response with the goal of arriving at new interventions for those who do not respond to existing treatments. We describe the process that led to the identification of specific executive deficits and their underlying neurobiology, as well as the rationale for targeting these symptoms as a part of a strategy intended to improve both executive dysfunction and depression. We then propose a strategy for further research in this emerging area.

RESULTS AND CONCLUSIONS

Despite significant developments, conventional antidepressant treatments leave many older adults still depressed and suffering. Psychotherapy may be effective in some depressed elders, although a recent review concluded that none of the available treatment studies meets stringent criteria for efficacy in the acute treatment of geriatric depression. Appropriately developed and targeted NBCCR, has the potential to serve as a novel treatment intervention for geriatric depression. Pathophysiological changes associated with executive dysfunction may be an appropriate target for NBCCR. Examining both behavioral changes and indices of structural integrity and functional change of networks related to cognitive and emotional regulation may lead to a novel treatment and elucidate the role of specific cerebral networks in geriatric depression.

Executive dysfunction and treatment response in late-life depression

OBJECTIVES

Executive dysfunction in geriatric depression has been shown to predict poor response to antidepressant medication. The purpose of this review is to clarify which aspects of executive functioning predict poor antidepressant treatment response.

METHODS

Literature review.

RESULTS

From our review, the aspects of executive functioning that appear to be associated with antidepressant response rates are verbal fluency and response inhibition. There is some indication that the semantic strategy component may account for the effects of verbal fluency, although evidence comes from one study and needs replication. Processing speed has been proposed as a substrate that may underlie the effects of executive dysfunction on treatment response. Although processing speed does not appear to account for the relationship between response inhibition and treatment outcome, this issue has yet to be assessed with respect to verbal fluency.

CONCLUSIONS

Verbal fluency and response inhibition are specific aspects of executive dysfunction that appear to impact antidepressant response rates. Disruption of the frontostriatal limbic circuit (particularly the anterior cingulate and dorsolateral prefrontal cortex) may explain the relation between these two mechanisms.

Cognitive improvement following treatment in late-life depression: relationship to vascular risk and age of onset

OBJECTIVES

To test the hypothesis that the degree of vascular burden and/or age of onset may influence the degree to which cognition can improve during the course of treatment in late-life depression.

DESIGN

Measurement of cognition both before and following 12 weeks of treatment with sertraline.

SETTING

University medical centers (Washington University and Duke University).

PARTICIPANTS

One hundred sixty-six individuals with late-life depression.

INTERVENTION

Sertraline treatment.

MEASUREMENTS

The cognitive tasks were grouped into five domains (language, processing speed, working memory, episodic memory, and executive function). We measured vascular risk using the Framingham Stroke Risk Profile measure. We measured T2-based white matter hyperintensities using the Fazekas criteria.

RESULTS

Both episodic memory and executive function demonstrated significant improvement among adults with late-life depression during treatment with sertraline. Importantly, older age, higher vascular risk scores, and lower baseline Mini-Mental State Examination scores predicted less change in working memory. Furthermore, older age, later age of onset, and higher vascular risk scores predicted less change in executive function.

CONCLUSIONS

These results have important clinical implications in that they suggest that a regular assessment of vascular risk in older adults with depression is necessary as a component of treatment planning and in predicting prognosis, both for the course of the depression itself and for the cognitive impairments that often accompany depression in later life.

Semantic organizational strategy predicts verbal memory and remission rate of geriatric depression

OBJECTIVE

This study tests the hypothesis that the use of semantic organizational strategy during the free-recall phase of a verbal memory task predicts remission of geriatric depression.

METHODS

Sixty-five older patients with major depression participated in a 12-week escitalopram treatment trial. Neuropsychological performance was assessed at baseline after a 2-week drug washout period. The Hopkins Verbal Learning Test-Revised was used to assess verbal learning and memory. Remission was defined as a Hamilton Depression Rating Scale score of ≤ 7 for 2 consecutive weeks and no longer meeting the DSM-IV-TR criteria for major depression. The association between the number of clusters used at the final learning trial (trial 3) and remission was examined using Cox's proportional hazards survival analysis. The relationship between the number of clusters utilized in the final learning trial and the number of words recalled after a 25-min delay was examined in a regression with age and education as covariates.

RESULTS

Higher number of clusters utilized predicted remission rates (hazard ratio, 1.26 (95% confidence interval, 1.04-1.54); χ(2)  = 4.23, df = 3, p = 0.04). There was a positive relationship between the total number of clusters used by the end of the third learning trial and the total number of words recalled at the delayed recall trial (F(3,58) = 7.93; p < 0.001).

CONCLUSIONS

Effective semantic strategy use at baseline on a verbal list learning task by older depressed patients was associated with higher rates of remission with antidepressant treatment. This result provides support for previous findings indicating that measures of executive functioning at baseline are useful in predicting antidepressant response.

Neuropsychological profiles and short-term outcome in late-onset depression

OBJECTIVE

Neuropsychological impairments are common in older persons with late-onset depression. This study examined the relationship between neuropsychological profiles and short-term outcome in late-onset depression.

METHODS

A total of 54 non-demented Chinese elders presented with their first major depressive episode after 60 years of age participated in this study and were treated according to a standardised protocol. At entry, they were assessed on neurological signs (Parkinsonian features and neurological soft signs) and neuropsychological measures (executive function, psychomotor-speed, attention and working memory, episodic memory, conceptualisation, construction and global cognitive function). The Hamilton Depression Rating Scale (HAM-D) was administered at baseline, the sixth and 12th week of treatment.

RESULTS

Abnormal fist-edge-palm (FEP) test, a sign reflecting impairment in motor sequencing, was more common in non-remitters (defined as HAM-D score above 7) at the 12th week of treatment.

CONCLUSIONS

The FEP test may be included in the clinical assessment for patients with late-onset depression to identify a susceptible group who may require more intensive treatment. Further research is warranted to ascertain the link between late-onset depression, neuropsychological deficits and prognosis.

The depression-executive dysfunction (DED) syndrome and response to antidepressants: a meta-analytic review

BACKGROUND

The depression-executive dysfunction (DED) model predicts that cognitive impairment, particularly executive dysfunction, is associated with poor response to antidepressant medication. A meta-analysis was undertaken to assess the evidence for this hypothesis.

METHODS

The PsycInfo and PubMed databases were searched to identify studies that examined response to antidepressant treatment in relation to pre-treatment cognitive performance. Systematic screening yielded 17 eligible publications, providing data for 1269 individuals. Ninety cognitive tests and subtests were used by these studies; 30 were used by more than one study. Weighted mean Cohen's d effect sizes, 95% confidence intervals and Fail Safe Ns were calculated for these 30 tests.

RESULTS

Five cognitive tests provided good discrimination (d(w) > 0.5) between patients who ultimately responded to antidepressant medication and those who failed to respond. One was a test of executive function but the remainder assessed other cognitive domains. Due to the small number of studies the influence of methodological factors, such as participant age and treatment duration, could not be statistically examined. However, a supplementary analysis restricted to nine studies where SSRIs were the only class of antidepressant revealed a similar pattern of results.

CONCLUSIONS

Performance on selected tests of executive function and non-executive cognitive functions is associated with response to anti-depressant medication in some populations. The available evidence does not provide strong support for the DED model.

Antidepressant medication and executive dysfunction: a deleterious interaction in late-life depression

OBJECTIVES

To determine whether there is differential response to placebo or citalopram among older patients with and without deficient response inhibition (DRI).

DESIGN

This is an 8-week, double-blind, placebo-controlled trial.

SETTING

Outpatient psychiatry.

PARTICIPANTS

Unipolar depressed patients aged 75 years and older.

INTERVENTION

Citalopram (20-40 mg/day) or placebo pill.

MEASUREMENTS

Baseline Stroop Color-Word Test and weekly 24-item Hamilton Rating Scale for Depression assessments.

RESULTS

Citalopram-treated patients with DRI did significantly worse than placebo-treated patients with DRI. Conversely, citalopram-treated patients without DRI did significantly better than placebo-treated patients without DRI.

CONCLUSION

Patients with late-life depression and DRI respond worse to selective serotonin reuptake inhibitor (SSRI) than placebo. These findings suggest that there may be a deleterious interaction between DRI and antidepressant medication in late-life depression and that the mechanism of SSRI and placebo response is different.

Change in cognitive functioning following acute antidepressant treatment in late-life depression

OBJECTIVE

Selective Serotonin Reuptake Inhibitors (SSRIs) are the most commonly prescribed medications for geriatric depression. The association of late-life depression and cognitive impairment has been well documented. However, there have been few placebo-controlled trials examining the impact of SSRIs on cognitive functioning.

DESIGN

Prepost neuropsychological (NP) data collected as part of an 8-week, double-blind, placebo-controlled trial of citalopram in depressed patients aged 75 years and older were used to examine change in cognitive functioning.

SETTING

University-affiliated outpatient psychiatry clinics.

PARTICIPANTS

One hundred seventy-four community-dwelling men and women aged 75 years or older with nonpsychotic unipolar depression.

MEASUREMENTS

NP assessments included mental status (Mini-Mental State Examination), psychomotor speed (Wechsler Adult Intelligence Scale-III Digit Symbol Subtest), reaction time (Choice Reaction Time), visual-spatial skill (Judgment of Line Orientation), executive functioning (Stroop Color/Word Test), and memory (Buschke Selective Reminding Test).

RESULTS

Differences in the pattern of change by treatment group depended on responder status. Citalopram nonresponders were the only group to decline on verbal learning and psychomotor speed. Citalopram responders showed significant improvement in visuospatial functioning, when compared with nonresponders in either condition, but their improvement was not greater than responders on placebo. Citalopram responders showed greater improvement on psychomotor speed than citalopram nonresponders, but their improvement was not greater than placebo responders or nonresponders.

CONCLUSIONS

Medication may have a deleterious effect on some aspects of cognition among patients aged 75 years and older who have not responded. This suggests that patients should not be maintained on a medication if they have not had an adequate response.