Memory impairment in patients with late-onset major depression: the effect of antidepressant therapy

A Systematic Review of Antidepressants and Psychotherapy Commonly Used in the Treatment of Late Life Depression for Their Effects on Cognition

Cognitive dysfunction is common in late life depression (LLD) and is a major risk factor for dementia. Recent studies show limited improvement in cognition with commonly employed treatments for LLD, contradicting the notion that cognition "returns to normal" with treatment. However, findings differ with the treatments used. The aim of this study is to perform a systematic review of studies of antidepressants and psychotherapies commonly employed in LLD to determine their effects on cognition, particularly processing speed, memory, and executive function. We searched for trials of acute phase treatment, in nondemented individuals 60 years and older with unipolar nonpsychotic Major Depressive Disorder, that assessed cognitive performance with neuropsychological tests before and after treatment. We compared the magnitude of change in cognition by examining within group effect sizes. Six antidepressant trials and two psychotherapy trials (both using Problem Solving Therapy)(PST) provided relatively comparable data that allowed for quantitative comparison. Nine other antidepressant trials provided descriptive findings. Sertraline and vortioxetine had significant positive effects on processing speed and memory. Duloxetine had significant effects on memory. The most selective SRIs-citalopram and escitalopram-had minimal effects on cognition and citalopram had adverse effects in depression nonresponders. PST had modest effects on processing speed and no effect on memory. Effects of practice and improvement in depression on cognition are examined. In all but one study, cognition was a secondary outcome and various quality indicators (e.g. blinding cognitive assessment to treatment) were often not reported. As a consequence, these findings must be considered preliminary.

Autobiographical memory impairment in genetic generalized epilepsies: neurocognitive and pathophysiological determinants

The neuropsychological breakdowns of autobiographical memory (AM) in adults suffering from genetic generalized epilepsy (GGE) are far from being understood and largely neglected.We aimed at identifying AM impairments in GGE by analyzing neurocognitive deficits in illness-related variables possibly affecting AM.Patients with GGE were compared to healthy controls (HCs), through semistructured interviews on AM, as well as neuropsychological measures to identify potential determinants of AM impairment.A single GGE group was formed by including patients with juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and epilepsy with generalized tonic-clonic seizures alone (EGTCA). Both GGE patients and HCs were tested for differential impairments in autobiographical episodic memory (AEM) and/or autobiographical semantic memory (ASEM), as well as other episodic- and/or semantic-memory and executive-function domains.The GGE patients exhibited overall impairment in autobiographical episodic and semantic information retrieval compared to HCs, both regarding childhood and the recent past. Furthermore, GGE patients demonstrated significantly poorer performance in immediate and delayed episodic recall, visuospatial working memory, visuoperceptual organization, face recognition memory, and verbal-executive functions compared to HCs. A distinct visuoperceptual involvement in retrieving childhood autobiographical episodic and semantic information has emerged, suggesting a potential connection between the latter AM systems and visual cognition.

Cognitive impairment of medicated patients with remitted depression and low anticholinergic activity

BACKGROUND

A recent meta-analysis has found that patients who have achieved remission of major depressive disorder (MDD) show cognitive dysfunction. Moreover, anticholinergic activity levels are associated with cognitive dysfunction, although the extent of these effects is unclear. Therefore, we measured serum anticholinergic activity (SAA) in blood samples of patients with remitted MDD and examined its relationship with cognitive function.

METHODS

We recruited 49 patients with remitted MDD following treatment and 165 healthy subjects. Subjects completed the Stroop test and the logical memory (LM) and visual reproduction (VR) subtests from the Wechsler Memory Scale-Revised. We compared cognitive function scores among those with SAA below the limit of quantification (SAA [-]), those with SAA above the limit of quantification (SAA [+]), and healthy controls.

RESULTS

The SAA (+) group scored significantly lower (p < 0.001) than the healthy control group on all tests, and the VR score of the SAA (-) group was significantly lower than that of the healthy control group (p = 0.024). LM scores in the SAA (+) group were significantly lower than that of the SAA (-) group (p = 0.033). Multiple regression analysis revealed a significant effect of SAA on the LM score (p = 0.015).

LIMITATIONS

Our study was a cross-sectional analysis of a small number of patients.

CONCLUSIONS

Our results support previous findings that the anticholinergic effect of antidepressants adversely affects cognitive function. Additionally, the cognitive impairment observed may persist because of MDD.

Cognitive Outcomes After Antidepressant Pharmacotherapy for Late-Life Depression: A Systematic Review and Meta-Analysis

OBJECTIVE

The authors evaluated whether treatment of late-life depression (LLD) with antidepressants leads to changes in cognitive function.

METHODS

A systematic review and meta-analysis of prospective studies of antidepressant pharmacotherapy for adults age 50 or older (or mean age of 65 or older) with LLD was conducted. MEDLINE, EMBASE, and PsycInfo were searched through December 31, 2022. The primary outcome was a change on cognitive test scores from baseline to after treatment. Secondary outcomes included the effects of specific medications and the associations between changes in depressive symptoms and cognitive test scores. Participants with bipolar disorder, psychotic depression, dementia, or neurological disease were excluded. Findings from all eligible studies were synthesized at a descriptive level, and a random-effects model was used to pool the results for meta-analysis.

RESULTS

Twenty-two studies were included. Thirteen of 19 studies showed an improvement on at least one cognitive test after antidepressant pharmacotherapy, with the most robust evidence for the memory and learning (nine of 16 studies) and processing speed (seven of 10 studies) domains and for sertraline (all five studies). Improvements in depressive symptoms were associated with improvement in cognitive test scores in six of seven relevant studies. The meta-analysis (eight studies; N=493) revealed a statistically significant overall improvement in memory and learning (five studies: effect size=0.254, 95% CI=0.103-0.404, SE=0.077); no statistically significant changes were seen in other cognitive domains. The evaluated risk of publication bias was low.

CONCLUSION

Antidepressant pharmacotherapy of LLD appears to improve certain domains of cognitive function, particularly memory and learning. This effect may be mediated by an improvement in depressive symptoms. Studies comparing individuals receiving pharmacotherapy with untreated control participants are needed.

A multi-method comparison of autobiographical memory impairments amongst younger and older adults

Objectives: Research indicates that, compared to younger adults, older adults have difficulty recalling memories of specific past events (those lasting less than 24 h) and this difficulty is associated with depression. These studies are largely confined to a single measure of specific memory recall and there are conflicting findings when alternative measures are used. This investigation provides the first comparison of memory specificity between younger and older adults using several different measures.Method: Older (n = 105) and younger (n = 88) adults completed the Autobiographical Memory Test (AMT), Autobiographical Memory Interview (AMI) and Sentence Completion for Events from the Past Test (SCEPT) and the number of specific memories was quantified for each measure. Participants also completed the Beck Depression Inventory Version II (BDI-II).Results: Compared to younger adults, older adults recalled fewer specific memories in the AMT and more specific memories in the AMI. This latter effect was particularly pronounced for memories related to childhood. There was no group difference in responses in the SCEPT. There was no evidence of an association between memory specificity and depression for any of the measures.Conclusion: Older adults have difficulty retrieving specific memories after cuing by nouns and adjectives, as in the AMT, but they have enhanced recall of specific memories after cuing by life periods, as in the AMI, and this is particularly true of memories related to childhood. Individual differences in memory specificity are not related to depression symptoms in healthy samples.

The Effect of Second-Generation Antidepressant Treatment on the Memory of Patients With Major Depressive Disorder: A Meta-analysis Study With Structural Equation Models

BACKGROUND

Major depressive disorder (MDD) has been linked to episodic memory deficits that may be improved after pharmacological treatment, but it is unclear whether there is a class of antidepressants that is more effective than others to ameliorate these deficits in MDD. In addition, the possible effects of clinical and sociodemographic variables on the improvement of MDD memory deficits after pharmacological treatment are currently unknown. Our aims are to study the possible neuropsychological effects of second-generation antidepressant classes on the episodic memory of MDD patients and to study the potential effects of clinical and demographic variables as moderators of the effects of antidepressants on the memory of depressed patients through a meta-analysis approach.

PROCEDURES

Nine articles were included in our study. A structural equation model meta-analysis was performed.

RESULTS

Our results suggest that selective serotonin reuptake inhibitors and serotonine-noradrenaline reuptake inhibitors would bring about a substantial improvement in the memory of depressed patients, whereas other antidepressant classes would cause rather modest effects. Our results also suggest that clinical and demographic variables play a very important role as mediators of memory improvement after MDD treatment. Thus, a relatively low level of symptom severity, a high degree of clinical improvement, a younger age, and more years of education were positively related to memory improvement after MDD treatment.

CONCLUSIONS

Although antidepressant class is an important variable linked to memory improvement in MDD, overall, the degree of memory amelioration in depression is very closely related to clinical and demographic variables of patients with depression.

Relationship Between Psychological Distress and Cognitive Function Differs as a Function of Obesity Status in Inpatient Heart Failure

Heart failure (HF) is a chronic medical condition rapidly growing in prevalence. Evidence links HF to cognitive decline, obesity, and psychological distress. The current study examined the association between cognitive function and ejection fraction (EF%), anxiety, depression, and obesity in inpatient HF. Patients completed the Generalized Anxiety Disorder 7-Item Scale (GAD-7), Patient Health Questionnaire 9-Item Scale (PHQ-9), and Mini-Cog while hospitalized for HF. Additional demographic and medical information was gathered via chart review. All models controlled for age. Of 117 patients assessed (49% male), 55% (n = 64) were obese. ANCOVA analyses were conducted comparing those with obesity and without on cognitive function: model A included EF%, model B included depression, and model C included anxiety. All three models were significantly related to cognitive function. There was a significant interaction effect of EF% and obesity and of anxiety and obesity to predict Mini-Cog scores. Post hoc partial correlational analyses revealed that anxiety was negatively associated with Mini-Cog scores among only patients without obesity. Depression was not significantly related to cognitive function in either group. However, patients with obesity demonstrated higher depression and anxiety than patients without. Results suggest that at lower EF%, and with higher anxiety, patients without obesity may be at greater risk of cognitive dysfunction than those with obesity. Cognitive dysfunction among HF patients with obesity may be independent of psychological distress. These findings may reflect the “obesity paradox” observed among HF patients, in that patients with obesity may have a different biopsychosocial presentation, which may lead to unexpected clinical outcomes. Further research is necessary to articulate the relationship of obesity and cognitive function in HF.

Individuals with psychotic-like experiences exhibit enhanced involuntary autobiographical memories

The relationship between hallucinations and stressful life events in psychosis is recognised, and has recently been supported by findings showing that the frequency of involuntary autobiographical memory and future projection predicts hallucination-proneness in the general population. To better understand the nature of this relationship, an online survey was conducted in 44 individuals with high Psychotic Like Experiences (PLE) and 44 matched controls, assessing the quantitative, qualitative and content characteristics of their involuntary autobiographical memories and future thoughts. Individuals with high PLE displayed a higher frequency of both involuntary autobiographical memory and future thought compared to controls. Moreover, the associated emotional intensity, feeling of reliving and intrusiveness were increased. Contrary to controls' memories, involuntary memories of individuals with high PLE more frequently referred to traumatic events and were associated with negative mood impact at retrieval. Taken together, these results can be seen as consistent with a relationship between involuntary memory and hallucination, by suggesting phenomenological and content related similarities between the two processes.

Investigating the relationship between age of onset of depressive disorder and cognitive function

OBJECTIVES

Depressive disorder is commonly associated with impaired cognitive function; however, it is unclear whether the age of onset of the first episode of depression, current depression severity, or historical severity of depressive episodes are associated with cognitive performance.

METHODS

This study examined baseline cross-sectional data from the ongoing online PROTECT study. A total of 7344 participants, 50 years or older, with a history of depression and no diagnosis of dementia were divided into three groups according to age of onset of their first depressive episode: early-onset, midlife-onset, and late-onset. Performance on measures of visuospatial episodic memory, executive function, verbal working, and visual working memory were evaluated. Demographic and clinical characteristics such as age, education, and severity of symptoms during their worst previous depressive episode and current depression severity were included in multivariate regression models.

RESULTS

The late-onset depression group scored significantly lower on the verbal reasoning task than the early-onset group while there were no significant differences found on the other tasks. Midlife-onset depression participants performed better in the visual episodic memory task, but worse on the verbal reasoning task, than early-onset depression participants. Current depression severity was negatively correlated with all four cognitive domains, while historical severity score was found to be significantly associated with cognitive performance on the verbal reasoning and spatial working memory tasks.

CONCLUSIONS

The most important indicator of cognitive performance in depression appears to be current, rather than historic depression severity; however, late-onset depression may be associated with more executive impairment than an early-onset depression.

Overgeneral autobiographical memory and depression in older adults: a systematic review

OBJECTIVES

Overgeneral autobiographical memory (OGM) is a well-researched phenomenon in working age adults with depression. However, the relevance and importance of OGM in older adult depression is not well established. The aim of this review was to synthesise existing literature on OGM and depressive symptoms in older adults under the framework of the Capture and Rumination, Functional Avoidance and Impaired Executive Control (CaR-FA-X) model.

METHOD

Literature searches were conducted using PsychINFO, PubMed and Web of Knowledge. Eighteen articles were reviewed.

RESULTS

OGM is elevated in healthy older adults compared to adults of working age, and further elevated in older adults with depression. Evidence supports the role of impaired executive function as a mechanism for OGM in older adults with depression, but no studies measured other components of the CaR-FA-X model (i.e. functional avoidance and rumination).

CONCLUSION

OGM is prevalent in older adults and more so for those with depression; however, there is no clear understanding of the underpinning mechanisms. It is recommended that future research looks at the role of functional avoidance and rumination, and at the use of memory specificity interventions being developed in the working age adult literature.

(R)-fluoxetine enhances cognitive flexibility and hippocampal cell proliferation in mice

Fluoxetine is a clinically successful antidepressant. It is a racemic mixture of (R) and (S) stereoisomers. In preclinical studies, chronic treatment with fluoxetine (10 mg/kg) had antidepressant effects correlated with increased hippocampal cell proliferation in adult rodents. However, the contribution of the enantiomers of fluoxetine is largely unknown. We investigated the effects of treatment with (R)- and (S)-fluoxetine on cognitive behavioral paradigms and examined cell proliferation in the hippocampus of C57BL/6J female mice. In a behavioral sequencing task using the IntelliCage system in which discriminated spatial patterns of rewarded and never-rewarded corners were reversed serially, (R)-fluoxetine-treated mice showed rapid acquisition of behavioral sequencing (compared with S-fluoxetine) and cognitive flexibility in subsequent reversal stages in intra- and inter-session analysis. (R)-fluoxetine also increased cell proliferation in the hippocampus, in particular in the suprapyramidal blade of the dentate gyrus. (R)-fluoxetine had superior effects to (S)-fluoxetine in elevated plus maze, forced-swim and tail-suspension tests. These results suggest that (R)-fluoxetine, which has been reported to have a shorter half-life than (S)-fluoxetine, has superior antidepressant effects and more consistently improves spatial learning and memory. This profile offers advantages in depression treatment and may also aid management of the neurocognitive impairments associated with depression.

Late-onset depression: issues affecting clinical care

A growing body of evidence suggests that late-onset depression (depression occurring for the first time in later life) differs from early-onset (recurrent) depression in terms of clinical features, aetiology, neuroanatomical substrates and prognosis. Some evidence suggests that late-onset depression is more associated with somatic symptoms, cognitive deficits, cerebral structural abnormalities, vascular disease (‘vascular depression’) and poorer treatment outcomes than is early-onset depression. Both general adult and old age psychiatrists face the challenges of managing late-onset depression. In this article we attempt to clarify specific issues relating to late-onset depression in terms of clinical features, aetiology, treatment response and prognosis.

Autobiographical memory deficits in patients with depression follow a temporal distribution

Autobiographical memory deficits are known in depression. The temporal distribution thereof across periods of life has rarely been considered yet. Autobiographical memories for 5 life periods were investigated in 27 depressed in-patients and compared to 31 matched healthy controls using the Bielefelder Autobiographisches Gedächtnis Inventar. Depressed patients reported significantly less details in memories dating from childhood to 30 years, correlating with severity of depression. Memories from childhood and recent periods were less positive in depressed patients. Thus, we found a distinct pattern of autobiographical memory deficits in depressed patients. Possible etiological factors, however, need further investigations.

Brain serotonin 4 receptor binding is inversely associated with verbal memory recall

BACKGROUND

We have previously identified an inverse relationship between cerebral serotonin 4 receptor (5-HT ₄R) binding and nonaffective episodic memory in healthy individuals. Here, we investigate in a novel sample if the association is related to affective components of memory, by examining the association between cerebral 5-HT ₄R binding and affective verbal memory recall.

METHODS

Twenty-four healthy volunteers were scanned with the 5-HT ₄R radioligand [¹¹C]SB207145 and positron emission tomography, and were tested with the Verbal Affective Memory Test-24. The association between 5-HT ₄R binding and affective verbal memory was evaluated using a linear latent variable structural equation model.

RESULTS

We observed a significant inverse association across all regions between 5-HT ₄R binding and affective verbal memory performances for positive (p = 5.5 × 10^-4) and neutral (p = .004) word recall, and an inverse but nonsignificant association for negative (p = .07) word recall. Differences in the associations with 5-HT ₄R binding between word categories (i.e., positive, negative, and neutral) did not reach statistical significance.

CONCLUSION

Our findings replicate our previous observation of a negative association between 5-HT ₄R binding and memory performance in an independent cohort and provide novel evidence linking 5-HT ₄R binding, as a biomarker for synaptic 5-HT levels, to the mnestic processing of positive and neutral word stimuli in healthy humans.

The Cognitive Functions in Adults with Chronic Pain: A Comparative Study

Background. Several studies have reported an association between chronic pain and reduction of cognitive abilities of adults living in Western cultures. No literature could be found on the relationship between chronic pain and cognition among Middle Eastern adults. Objective. To compare four of the most commonly reported cognitive domains [memory, attention, processing speed, and executive functioning] among Middle Eastern adults with and without chronic pain. Methods. This matched group comparative study included 69 community residing and functionally independent Middle Eastern adults. Forty participants had chronic pain and 29 were pain-free. We administered five standardized cognitive assessments that are independent of culture and language to measure variable tasks of memory, attention, processing speed, and executive functioning. The study was conducted in a rehabilitation research setting with a controlled environment. Results. Evidence of decreased cognitive processing was found in patients with chronic pain. The chronic pain participants performed significantly worse than the pain-free participants on the cognitive measures of long-term memory, selective attention, processing speed, and executive functioning. Conclusion. The effect of Middle Eastern culture on the cognitive abilities of patients with chronic pain was negligible. Despite the wide variations between Eastern and Western cultures, the performance of our Middle Eastern participants in this study was consistent with performance of Western adults reported in previous studies.

Elucidating the link between the modifiable risk factors of Alzheimer's disease and neuroinflammation

Increased worldwide longevity through medical interventions, although beneficial, has allowed the age-related Alzheimer's disease (AD) to become an epidemic of the 21st century. AD pathology involves adverse activation of microglia, the immune cells of the brain and resulting chronic neuroinflammation. Certain diets, physical inactivity and Type 2 diabetes mellitus have been identified as the risk factors for developing AD, which may increase the risk of AD by neuroimmune mechanisms primarily through the overactivation of microglia. Thus, modifying these risk factors may represent an alternative therapeutic strategy for lowering the incidence of AD. We highlight the link between select modifiable risk factors and neuroimmune mechanisms, and demonstrate that by controlling microglial activation and neuroinflammation the prevalence of AD may be decreased.

Effects of sertraline, duloxetine, vortioxetine, and idazoxan in the rat affective bias test

RATIONALE

Affective biases seemingly play a crucial role for the onset and development of depression. Acute treatment with monoamine-based antidepressants positively influences emotional processing, and an early correction of biases likely results in repeated positive experiences that ultimately lead to improved mood.

OBJECTIVES

Using two conventional antidepressants, sertraline and duloxetine, we aimed to forward the characterization of a newly developed affective bias test (ABT) for rats. Further, we examined the effect of vortioxetine, a recently approved antidepressant, and the α₂ adrenoceptor antagonist idazoxan on affective biases.

METHODS

Sprague Dawley rats were tested in an affective bias test using a fully balanced within-subject study design. Rats learned to associate two different digging substrates with a reward during six reward-pairing days. The absolute value of the rewards was identical, but the affective state at the time of learning induces a positive or negative bias towards the treatment-paired digging substrate at recall. The choice bias between the two digging substrates at recall represents the affective bias. Sertraline (1, 3 and 10 mg/kg), duloxetine (1, 3 and 10 mg/kg), vortioxetine (1, 3 and 10 mg/kg) and idazoxan (3 and 10 mg/kg) were tested in the ABT.

RESULTS AND CONCLUSIONS

All four drugs, regardless of their mechanism of action, induced a positive affective bias in the ABT, although the overall effect of treatment was not statistically significant for sertraline and duloxetine. The largest effects were induced by vortioxetine and idazoxan, both of which caused significant positive biases at all tested doses.

Cognitive Function before and during Treatment with Selective Serotonin Reuptake Inhibitors in Patients with Depression or Obsessive-Compulsive Disorder

Objectives. Identification of adverse effects of selective serotonin reuptake inhibitors (SSRIs) is of great importance due to their extensive use in medicine. Some studies have reported the effects of SSRIs on cognitive functions, but the results are conflicting. This study was designed to assess the effect of these drugs on cognition of patients with depression or obsessive-compulsive disorder (OCD). Methods. Patients with depression or OCD, naïve to therapy, and candidates of receiving one drug from SSRI class, voluntarily, entered this study. Mini-Mental State Examination (MMSE) test was the tool to assess their cognitive functions. MMSE scores of each patient were recorded prior to taking SSRIs and at weeks 3, 5, and 8 of drug therapy. Results. 50 patients met our inclusion criteria, with a baseline mean MMSE score of 23.94. At 3, 5, and 8 weeks of treatment, the mean scores were 22.1, 21.4, and 20.66, respectively. With a p value of <0.0001, the gradual decline was statistically significant. Conclusion. The MMSE scores of our patients showed a gradual decline over the consecutive weeks after taking SSRI drugs. It seems that the use of SSRIs in patients with depression or OCD, can cause cognitive dysfunction in the acute phase of treatment.

Systematic Review of Cognitive Effects of Electroconvulsive Therapy in Late-Life Depression

OBJECTIVE

Late-life depression (LLD) is known to negatively impact cognition even after remission of mood symptoms. Electroconvulsive therapy (ECT) and newer nonconvulsive electrical and magnetic brain stimulation interventions have been shown to have cognitive effects in patients with neuropsychiatric disorders.

METHODS

This review systematically assessed the effects of ECT on cognition in LLD. EMBASE, Ovid Medline, and PsycINFO were systematically searched through June 2015. The search was limited to publications from peer-reviewed journals in the English language.

RESULTS

A total of 5,154 publications was identified; 318 were reviewed in full text, of which 39 publications related to ECT were included. We focused this review only on ECT because evidence on newer interventions was deemed insufficient for a systematic review. This literature suggests increased rates of interictal and postictal cognitive decline with ECT but no long-term (i.e., 6 months or longer) deleterious effects on cognition. Instead, long-term cognitive outcomes with ECT have been reported as either not changed or improved. This literature favors nondominant unilateral ECT over bilateral ECT for cognition.

CONCLUSION

Published literature on brain stimulation interventions in LLD is mainly limited to ECT. This literature suggests that deleterious effects of ECT in LLD are limited and transient, with better cognitive outcomes with unilateral ECT. There is not enough evidence to fully characterize long-term deleterious effects of ECT or effects of newer brain stimulation techniques on cognition in LLD.

Cognitive Dysfunction in Major Depressive Disorder. A Translational Review in Animal Models of the Disease

Major Depressive Disorder (MDD) is the most common psychiatric disease, affecting millions of people worldwide. In addition to the well-defined depressive symptoms, patients suffering from MDD consistently complain about cognitive disturbances, significantly exacerbating the burden of this illness. Among cognitive symptoms, impairments in attention, working memory, learning and memory or executive functions are often reported. However, available data about the heterogeneity of MDD patients and magnitude of cognitive symptoms through the different phases of MDD remain difficult to summarize. Thus, the first part of this review briefly overviewed clinical studies, focusing on the cognitive dysfunctions depending on the MDD type. As animal models are essential translational tools for underpinning the mechanisms of cognitive deficits in MDD, the second part of this review synthetized preclinical studies observing cognitive deficits in different rodent models of anxiety/depression. For each cognitive domain, we determined whether deficits could be shared across models. Particularly, we established whether specific stress-related procedures or unspecific criteria (such as species, sex or age) could segregate common cognitive alteration across models. Finally, the role of adult hippocampal neurogenesis in rodents in cognitive dysfunctions during MDD state was also discussed.

Management of Cognitive Impairment in Heart Failure

OPINION STATEMENT

Cognitive impairment (CI) is an inclusive term to describe trouble with memory, learning, concentration, or decision-making. CI is highly prevalent in patients with heart failure (HF) and is known to be associated with a variety of poor outcomes. While published HF guidelines recommend screening for CI, they do not indicate how, due to a lack of consensus in the literature about which instrument to use. Our recommendation is to use the Mini-Cog for this purpose because of its brevity and utility in identifying patients with HF at high risk for hospitalization or mortality. At this time, there is minimal published clinical trial evidence about how to manage CI in patients with HF. Reasonable approaches to management may include following guideline-directed medical therapy for HF, treatment of hypertension and atrial fibrillation, management of depression, proactive diagnosis and treatment of sleep apnea, and encouragement of aerobic exercise and weight loss. Left ventricular assist device (LVAD) therapy in patients with Stage D HF may improve CI in the short term after implantation, though there is a risk of worsening CI in the intermediate and long term. Clinicians who care for patients with HF should routinely screen for CI and when identified should encourage interventions to support self-care, increase family involvement, and arrange for more frequent follow-up.

Utility of the Neurobehavioral Cognitive Status Examination (COGNISTAT) in differentiating between depressive states in late-life depression and late-onset Alzheimer's disease: a preliminary study

BACKGROUND

It is often difficult to differentiate between the depressive states seen in late-life depression and late-onset Alzheimer' disease (AD) in the clinical setting.

METHODS

Thirty-four outpatients were recruited, all fulfilling the criteria of aged 65 years or above, scores of 14 or more on the Hamilton depression rating scale (HAM-D), and 26 or less on the Mini-Mental State Examination (MMSE). At the initial visit, they were administered the Neurobehavioral Cognitive Status Examination (COGNISTAT). At 1 month, a diagnosis of either senile depression (n = 24) or Alzheimer' disease (n = 10) was made.

RESULTS

The COGNISTAT revealed that the late-life depression group showed significantly higher scores in orientation and comprehension subtests compared with the AD group. At the study endpoint (6 months after treatment), MMSE detected significant improvements in the late-life depression group (n = 15), but no changes in the late-onset AD group (n = 7). Scores for memory, similarities, and judgment on the second COGNISTAT were significantly improved in the depressed group, whereas calculation scores deteriorated significantly in the AD group.

CONCLUSION

The COGNISTAT could prove useful in differentiating late-life depression from late-onset AD, despite similar scores on MMSE.

Influence of Pharmacotherapy on Cognitive Functions in Depression: A Review of the Literature

In addition to irregularities relating to the emotional sphere, the cognitive impairment in depression is a part of the clinical picture of this affective disorder. Some of the cognitive deficits may be associated with the severity of psychopathological symptoms of depression, while others are more established and can also occur during periods of remission. The participation in cognitive functioning of people with depression have a number of factors: the severity of symptoms, concurrent anxiety disorders, gender, age, education, duration of the disease, and number of previous episodes, as well as general somatic health or medication used. The pharmacological treatment may have varying impact on the different areas of cognition. Research on pharmacotherapy for depression and its impact on cognitive functioning continue and are very popular among clinicians and researchers. The relationship between antidepressants and cognitive abilities is always modulated by the type of depressive disorder, neurobiological factors, and demographic variables. This article presents a review of the studies relating to assessment of the effects of various antidepressants on cognitive abilities among patients with depression.

Antidepressant Use and Cognitive Decline: The Health and Retirement Study

BACKGROUND

Depression is associated with cognitive impairment and dementia, but whether treatment for depression with antidepressants reduces the risk for cognitive decline is unclear. We assessed the association between antidepressant use and cognitive decline over 6 years.

METHODS

Participants were 3714 adults aged 50 years or more who were enrolled in the nationally representative Health and Retirement Study and had self-reported antidepressant use. Depressive symptoms were assessed using the 8-item Center for Epidemiologic Studies Depression Scale. Cognitive function was assessed at 4 time points (2004, 2006, 2008, 2010) using a validated 27-point scale. Change in cognitive function over the 6-year follow-up period was examined using linear growth models, adjusted for demographics, depressive symptoms, comorbidities, functional limitations, and antidepressant anticholinergic activity load.

RESULTS

At baseline, cognitive function did not differ significantly between the 445 (12.1%) participants taking antidepressants and those not taking antidepressants (mean, 14.9%; 95% confidence interval, 14.3-15.4 vs mean, 15.1%; 95% confidence interval, 14.9-15.3). During the 6-year follow up period, cognition declined in both users and nonusers of antidepressants, ranging from -1.4 change in mean score in those with high depressive symptoms and taking antidepressants to -0.5 change in mean score in those with high depressive symptoms and not taking antidepressants. In adjusted models, cognition declined in people taking antidepressants at the same rate as those not taking antidepressants. Results remained consistent across different levels of baseline cognitive function, age, and duration of antidepressant use (prolonged vs short-term).

CONCLUSIONS

Antidepressant use did not modify the course of 6-year cognitive change in this nationally representative sample.

Effects of remission speed and improvement of cognitive functions of depressed patients

Major depressive disorder (MDD) presents neuropsychological alterations which improve after the treatment, but it might be mediated by clinical variables. Our goal is to study whether the speed of remission of MDD bears any relation to the improvement of the patients' cognitive functioning after a successful treatment. We carried out clinical and neuropsychological assessments of 51 patients with MDD. After these procedures they underwent a 24-week treatment with fluoxetine, and were assessed again with the same battery used prior to treatment. They were arranged into three groups according to how rapid their symptoms remitted. The patients with a rapid remission presented improvements in working memory, speed of information processing, and some executive functions, unlike the other groups. Rapid remitters also improved in episodic memory and executive functions more than the other patients.

The role of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in depression: central mediators of pathophysiology and antidepressant activity?

Depression is a major psychiatric disorder affecting more than 120 million people worldwide every year. Changes in monoaminergic transmitter release are suggested to take part in the pathophysiology of depression. However, more recent experimental evidence suggests that glutamatergic mechanisms might play a more central role in the development of this disorder. The importance of the glutamatergic system in depression was particularly highlighted by the discovery that N-methyl-D-aspartate (NMDA) receptor antagonists (particularly ketamine) exert relatively long-lasting antidepressant like effects with rapid onset. Importantly, the antidepressant-like effects of NMDA receptor antagonists, but also other antidepressants (both classical and novel), require activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Additionally, expression of AMPA receptors is altered in patients with depression. Moreover, preclinical evidence supports an important involvement of AMPA receptor-dependent signaling and plasticity in the pathophysiology and treatment of depression. Here we summarize work published on the involvement of AMPA receptors in depression and discuss a possible central role for AMPA receptors in the pathophysiology, course and treatment of depression.

Treatment-related improvement in neuropsychological functioning in suicidal depressed patients: paroxetine vs. bupropion

Neuropsychological dysfunction is associated with risk for suicidal behavior, but it is unknown if antidepressant medication treatment is effective in reducing this dysfunction, or if specific medications might be more beneficial. A comprehensive neuropsychological battery was administered at baseline and after 8 weeks of treatment within a randomized, double-blind clinical trial comparing paroxetine and bupropion in patients with DSM-IV Major Depressive Disorder and either past suicide attempt or current suicidal thoughts. Change in neurocognitive performance was compared between assessments and between medication groups. Treatment effects on the Hamilton Depression Rating Scale and Scale for Suicide Ideation were compared with neurocognitive improvement. Neurocognitive functioning improved after treatment in all patients, without clear advantage for either medication. Improvement in memory performance was associated with a reduction in suicidal ideation independent of the improvement of depression severity. Overall, antidepressant medication improved neurocognitive performance in patients with major depression and suicide risk. Reduced suicidal ideation was best predicted by a combination of the independent improvements in both depression symptomatology and verbal memory. Targeted treatment of neurocognitive dysfunction in these patients may augment standard medication treatment for reducing suicidal behavior risk.

Memory Impairment following Acute Tricyclic Antidepressants Overdose

Background. Psychiatric consultation is necessary for all patients with intentional poisoning and its reliability depends on the proper function of patients' memory performance. This study aimed to determine the possible memory impairment following acute TCAs' poisoning. Materials and Methods. In this cross-sectional study, patients with acute TCAs poisoning were allocated to two groups of severe poisoning (with coma, seizures, cardiac arrhythmias, hypotension, and a wide QRS complex) and mild-to-moderate poisoning according to their clinical presentation at the time of hospital admission. All patients underwent memory performance test both immediately and 24 hours after their initial consciousness after admission, using Wechsler Memory Scale (WMS-IV). Results. During the study period, 67 TCA-poisoned patients (aged, 20-64 years) were evaluated, of which 67.2% were female. The mean memory scores of patients immediately and 24 hours after the initial consciousness were 31.43 ± 9.02 and 50.62 ± 9.12, respectively (P < 0.001). Twenty-four hours after the initial consciousness, memory score was statistically correlated with the amount of ingested drug and the intoxication severity. Conclusion. Following the recovery from somatic symptoms of acute TCA poisoning, patients may still suffer from memory impairment and it seems that this time is not suitable for performing a reliable psychiatric consultation.

Drug-, dose- and sex-dependent effects of chronic fluoxetine, reboxetine and venlafaxine on open-field behavior and spatial memory in rats

In an effort to address the need to include both sexes in studies of effects of the SSRI fluoxetine, the NRI reboxetine and the SNRI venlafaxine on anxiety-related behavior and memory along with the use of chronic drug administration, male and female PVG/c rats were fed diets containing two doses of each drug for 21 days. The rats' anxiety level was then assessed in an open field. Short-term spatial memory for a brightness change in a Y maze was also measured. While there was little evidence of anxiolytic effects of any of the drugs, both fluoxetine and, to a lesser extent, venlafaxine appeared to be mainly anxiogenic in their action depending on both dose and sex. Reboxetine was relatively ineffective in this respect. Ability to locate the Y-maze arm that had changed (from white to black) seemed to be impaired for male (but not female) rats by both fluoxetine and venlafaxine and, to a much lesser extent, by reboxetine. Given the relative ineffectiveness of reboxetine in either test, it is possible that the effects of the other two drugs on both anxiety and memory were mainly due to their serotonin reuptake inhibiting properties. The differences that occurred between males and females in responsiveness to all three drugs supported the long-held view that both sexes should be investigated in studies of this sort, especially in view of reports of sex differences in effects of clinically prescribed antidepressants.

Cyr N, Lavretsky H. The patterns of cognitive and functional impairment in amnestic and non-amnestic mild cognitive impairment in geriatric depression

OBJECTIVES

Depressed older adults are at risk for the development of mild cognitive impairment (MCI), but few studies have characterized MCI subtypes in geriatric depression. The objective of this study was to identify the clinical patterns of MCI in late-life depression.

DESIGN

Baseline demographic, clinical, and neuropsychological test data collected as part of a randomized antidepressant trial for geriatric depression.

SETTING

UCLA-based outpatient clinic.

PARTICIPANTS

One hundred thirty-eight older adults with major depression.

MEASUREMENTS

A neuropsychological test battery and comprehensive evaluations of depression, apathy, quality of life, medical burden, and vascular risk factors.

RESULTS

Seventy-one participants (51%) had MCI and 67 (49%) were cognitively normal. Of subjects with MCI, 14 (20%) had amnestic MCI and 57 (80%) had non-amnestic MCI. Overall, patients with MCI had greater depression severity, poorer quality of life, and worse performance on the Mini-Mental State Exam than patients without MCI. Patients with non-amnestic MCI had significantly greater depression severity than patients without MCI. Across all subjects, depression severity correlated with impaired performance in language and visuospatial functioning.

CONCLUSION

Our findings suggest that MCI is associated with greater severity of depression, poorer quality of life, and worse global cognitive function. Overall, subtypes of MCI in geriatric depression differ in the patterns of functional impairment, which may require different therapeutic approaches.

Pharmacological and non-pharmacological interventions to improve cognitive dysfunction and functional ability in clinical depression--a systematic review

Cognitive dysfunction is of clinical significance and exerts longstanding implication on patients׳ function. Pharmacological and non-pharmacological treatments of cognitive dysfunction are emerging. This review evaluates pharmacological and non-pharmacological treatments of cognitive impairment primarily in the domains of memory, attention, processing speed and executive function in clinical depression. A total of 35 studies were retrieved from Pubmed, PsycInfo and Scopus after applying inclusion and exclusion criteria. Results show that various classes of antidepressants exert improving effects on cognitive function across several cognitive domains. Specifically, studies suggest that SSRIs, the SSRE tianeptine, the SNRI duloxetine, vortioxetine and other antidepressants such as bupropion and moclobemide may exert certain improving effects on cognitive function in depression, such as in learning and memory and executive function. Class-specific cognitive domains or specific dose-response relationships were not identified yet. The few non-pharmacological studies conducted employing cognitive orientated treatments and cognitive remediation therapy show promising results for the improvement of cognitive impairment in depression. However, several methodological constraints of studies limit generalizability of the results and caution the interpretation. Future direction should consider the development of a neuropsychological consensus cognitive battery to support the discovery, clinical assessment, comparison of studies and registration of new agents in clinical depression.

Comparative study of cognitive impairment between medicated and medication-free patients with remitted major depression: class-specific influence by tricyclic antidepressants and newer antidepressants

Patients with major depressive disorder (MDD) are known to present with cognitive deficits; however, the presence of these deficits in the remitted state have been inconsistent. One of the most important factors potentially contributing to inconsistencies between studies may be the influence of medications. To explore the influence of antidepressants on cognitive performance in remitted MDD, we evaluated memory and executive functions using Wechsler Memory Scale-Revised and Stroop Color and Word Test, and compared performance among 50 medicated (29 treated with tricyclic antidepressants [TCA], 21 treated with selective serotonin reuptake inhibitors or serotonin noradrenalin reuptake inhibitors) and 19 medication-free MDD patients and 31 controls. The results showed that all 3 MDD groups had significantly lower performance for verbal memory compared with controls. Both medicated groups showed significantly lower performance for visual memory compared with controls; however, the medication-free group did not differ from controls. For the executive function, only the TCA group showed a significantly lower performance compared with controls. These results suggest that cognitive impairment remained even in remitted patients with MDD, however, part of this impairment may be influenced by class-specific antidepressant side effects.

Impact of pharmacological and psychological treatment methods of depressive and anxiety disorders on cognitive functioning

Anxiety and depressive disorders are characterized by a number of clinical symptoms like decreased mood, apathy, anhedonia and anxiety. An important element of the clinical picture is also neurocognitive impairment. The most common treatment methods for depression and anxiety are pharmacology, psychotherapy or a combination of both methods. The data from literature show that those treatment methods lead to an improvement of clinical symptoms, but they exert a possible impact on cognitive functions. However the study results referring both to the role of pharmacological treatment and psychotherapy in this domain are still inconsistent. There is an increasing number of accessible data confirming the positive effects of those clinical interventions on cognitive functioning of anxiety and depressive patients, but the interpretation is complicated because of differences in methodology as well as examined sample size and their characteristics. More studies are then needed to describe this phenomenon.

Does duloxetine improve cognitive function independently of its antidepressant effect in patients with major depressive disorder and subjective reports of cognitive dysfunction?

Introduction. Cognitive deficits are commonly reported by patients with major depressive disorder (MDD). Duloxetine, a dual serotonin/noradrenaline reuptake inhibitor, may improve cognitive deficits in MDD. It is unclear if cognitive improvements occur independently of antidepressant effects with standard antidepressant medications. Methods. Thirty participants with MDD who endorsed cognitive deficits at screening received 12-week duloxetine treatment. Twenty-one participants completed treatment and baseline and posttreatment cognitive testing. The Cambridge Neuropsychological Test Automated Battery was used to assess the following cognitive domains: attention, visual memory, executive function/set shifting and working memory, executive function/spatial planning, decision making and response control, and verbal learning and memory. Results. Completers showed significant cognitive improvements across several domains on tasks assessing psychomotor function and mental processing speed, with additional improvements in visual and verbal learning and memory, and affective decision making and response control. Overall significance tests for executive function tasks were also significant, although individual tasks were not, perhaps due to the small sample size. Most notably, cognitive improvements were observed independently of symptom reduction on all domains except verbal learning and memory. Conclusions. Patients reporting baseline cognitive deficits achieved cognitive improvements with duloxetine treatment, most of which were independent of symptomatic improvement. This trial is registered with NCT00933439.

Cognitive impairment in euthymic major depressive disorder: a meta-analysis

BACKGROUND

There is evidence to suggest that cognitive deficits might persist beyond the acute stages of illness in major depressive disorder (MDD). However, the findings are somewhat inconsistent across the individual studies conducted to date. Our aim was to conduct a systematic review and meta-analysis of existing studies that have examined cognition in euthymic MDD patients.

METHOD

Following a systematic search across several publication databases, meta-analyses were conducted for 27 empirical studies that compared euthymic adult MDD patients (895 participants) and healthy controls (997 participants) across a range of cognitive domains. The influence of demographic variables and confounding factors, including age of onset and recurrent episodes, was examined.

RESULTS

Compared with healthy controls, euthymic MDD patients were characterized by significantly poorer cognitive functions. However, the magnitude of observed deficits, with the exception of inhibitory control, were generally modest when late-onset cases were excuded. Late-onset cases demonstrated significantly more pronounced deficits in verbal memory, speed of information processing and some executive functions.

CONCLUSIONS

Cognitive deficits, especially poor response inhibition, are likely to be persistent features, at least of some forms, of adult-onset MDD. More studies are necessary to examine cognitive dysfunction in remitted psychotic, melancholic and bipolar spectrum MDD. Cognitive deficits overall appear to be more common among patients with late-onset depression, supporting the theories suggesting that possible vascular and neurodegenerative factors play a role in a substantial number of these patients.

Time course for memory dysfunction in early-life and late-life major depression: a longitudinal study from the Juntendo University Mood Disorder Project

BACKGROUND

Previous studies have demonstrated that patients with depression also have memory dysfunctions during depressive episodes. These dysfunctions partially remain immediately after remission from a depressive state; however, it is unclear whether these residual memory dysfunctions may disappear through long-term remission from depression. The present study compared patients during early-life (age<60) and late-life (age ≥ 60) depression while in their remitted stage with healthy controls to elucidate the impact of a long-term course on memory.

METHODS

Logical memory from the Wechsler Memory Scale-Revised was administered to 67 patients with major depressive disorder (MDD) (47 patients with early-life depression and residual 20 patients with late-life depression) and 50 healthy controls. MDD patients received memory assessments at the time of their initial remission and at a follow-up three years after remission.

RESULTS

At the time of initial remission, scores for logical memory were significantly lower in both patient groups compared to matched controls. At follow-up, memory dysfunction for early-life MDD patients disappeared, whereas scores in the late-life MDD group remained significantly lower than those of matched controls.

LIMITATIONS

All patients in the present study were on antidepressant medications.

CONCLUSIONS

Our findings suggested that the progress of memory performance in late-life MDD patients may be different from early-life MDD patients.

Sensitivity of cognitive tests in four cognitive domains in discriminating MDD patients from healthy controls: a meta-analysis

BACKGROUND

We performed a meta-analysis in order to determine which neuropsychological domains and tasks would be most sensitive for discriminating between patients with major depressive disorder (MDD) and healthy controls.

METHODS

Relevant articles were identified through a literature search of the PubMed and Cochrane Library databases for the period between January 1997 and May 2011. A meta-analysis was conducted using the standardized means of individual cognitive tests in each domain. The heterogeneity was assessed, and subgroup analyses according to age and medication status were performed to explore the sources of heterogeneity.

RESULTS

A total of 22 trials involving 955 MDD patients and 7,664 healthy participants were selected for our meta-analysis. MDD patients showed significantly impaired results compared with healthy participants on the Digit Span and Continuous Performance Test in the attention domain; the Trail Making Test A (TMT-A) and the Digit Symbol Test in the processing speed domain; the Stroop Test, the Wisconsin Card Sorting Test, and Verbal Fluency in the executive function domain; and immediate verbal memory in the memory domain. The Finger Tapping Task, TMT-B, delayed verbal memory, and immediate and delayed visual memory failed to separate MDD patients from healthy controls. The results of subgroup analysis showed that performance of Verbal Fluency was significantly impaired in younger depressed patients (<60 years), and immediate visual memory was significantly reduced in depressed patients using antidepressants.

CONCLUSIONS

Our findings have inevitable limitations arising from methodological issues inherent in the meta-analysis and we could not explain high heterogeneity between studies. Despite such limitations, current study has the strength of being the first meta-analysis which tried to specify cognitive function of depressed patients compared with healthy participants. And our findings may provide clinicians with further evidences that some cognitive tests in specific cognitive domains have sensitivity to discriminate MDD patients from healthy controls.

Chronic dim light at night provokes reversible depression-like phenotype: possible role for TNF

The prevalence of major depression has increased in recent decades and women are twice as likely as men to develop the disorder. Recent environmental changes almost certainly have a role in this phenomenon, but a complete set of contributors remains unspecified. Exposure to artificial light at night (LAN) has surged in prevalence during the past 50 years, coinciding with rising rates of depression. Chronic exposure to LAN is linked to increased risk of breast cancer, obesity and mood disorders, although the relationship to mood is not well characterized. In this study, we investigated the effects of chronic exposure to 5 lux LAN on depression-like behaviors in female hamsters. Using this model, we also characterized hippocampal brain-derived neurotrophic factor expression and hippocampal dendritic morphology, and investigated the reversibility of these changes 1, 2 or 4 weeks following elimination of LAN. Furthermore, we explored the mechanism of action, focusing on hippocampal proinflammatory cytokines given their dual role in synaptic plasticity and the pathogenesis of depression. Using reverse transcription-quantitative PCR, we identified a reversible increase in hippocampal tumor necrosis factor (TNF), but not interleukin-1β, mRNA expression in hamsters exposed to LAN. Direct intracerebroventricular infusion of a dominant-negative inhibitor of soluble TNF, XPro1595, prevented the development of depression-like behavior under LAN, but had no effect on dendritic spine density in the hippocampus. These results indicate a partial role for TNF in the reversible depression-like phenotype observed under chronic dim LAN. Recent environmental changes, such as LAN exposure, may warrant more attention as possible contributors to rising rates of mood disorders.

Association between severity of depression and self-perceived cognitive difficulties among full-time employees

OBJECTIVE

To assess the relationship between self-perceived deficits in cognition and severity of depression reported by individuals in full-time employment.

METHOD

Individuals ≥ 18 years of age employed full-time with diagnosed depression excluding bipolar disorder (participants had to be told by a doctor that they had depression based on DSM-IV criteria) completed a 25-minute Web-based survey in February 2010 (study population identified by Harris Interactive, Rochester, New York). The survey used the Perceived Deficits Questionnaire (PDQ) to assess self-perceived cognitive impairment and the 9-item Patient Health Questionnaire (PHQ-9) to assess depression severity. The 20-question PDQ was used to assess self-perceived cognitive difficulties within the domains of prospective memory, retrospective memory, attention/concentration, and planning/organization (range, 0-20: higher scores indicate greater impairment). Subjects answered how often they experienced such difficulties during the previous 4 weeks (0 = never, 1 = rarely, 2 = sometimes, 3 = often, 4 = almost always). The scale ranges from 0-20 for each of the 4 subscales, with higher scores indicating greater cognitive impairment. The impact of depression on PDQ scores was assessed using a trend test based on an analysis of covariance controlling for potential confounders.

RESULTS

Subjects (N = 1,051) (58% women) had a mean ± SD age of 47 ± 12 years; 38% held professional employment. PHQ-9 scores indicated that 423 employees (40.3%) had no depressive symptoms at the time of the survey, 319 (30.4%) had mild depression, 166 (15.8%) had moderate depression, 82 (7.8%) had moderately severe depression, and 61 (5.8%) had severe depression. Perceived cognitive functioning worsened with increasing severity of depression symptoms (P < .0001) on the basis of PDQ scores. On the basis of responses to the PDQ, in the current study, most impairment was seen in the attention/concentration and planning/organization subscales in severely depressed subjects (12.2 for both) compared with those with no depressive symptoms (4.4 and 3.5, respectively), indicating more cognitive impairment in the severely depressed subjects compared to the subjects with no depression.

CONCLUSIONS

In currently employed individuals, self-perceived cognitive dysfunction worsened with increasing severity of depressive symptoms. This association was independent of antidepressant use. The greatest impairment in self-perceived cognition was observed in the planning/organization and attention/concentration subscales.

The effect of systemic chemotherapy on neurogenesis, plasticity and memory

Chemotherapy has been enormously successful in treating many forms of cancer and improving patient survival rates. With the increasing numbers of survivors, a number of cognitive side effects have become apparent. These have been called "chemobrain" or "chemofog" among patient groups, who describe the symptoms as a decline in memory, concentration and executive functions. Changes which, although subtle, can cause significant distress among patients and prevent a return to the quality of life experienced before treatment. This cognitive side effect of chemotherapy was not anticipated as it had been assumed that chemotherapy agents, administered systematically, could not cross the blood-brain barrier and that the brain was therefore protected from their action. It is now realised that low concentrations of many chemotherapy agents cross the blood-brain barrier and even those that are completely prevented from doing so, can induce the production of inflammatory cytokines in peripheral tissues which in turn can cross the blood-brain barrier and impact on the brain. A large number of patient studies have shown that cognitive decline is found in a proportion of patients treated with a variety of chemotherapy agents for different types of cancer. The deficits experienced by these patients can last for up to several years and have a deleterious effect on educational attainment and ability to return to work. Imaging studies of patients after systemic chemotherapy show that this treatment produces structural and functional changes in the brain some of which seem to persist even when the cognitive deficits have ceased. This suggests that, with time, brain plasticity may be able to compensate for the deleterious effects of chemotherapy treatment. A number of mechanisms have been suggested for the changes in brain structure and function found after chemotherapy. These include both central and peripheral inflammatory changes, demyelination of white matter tracts, a reduction in stem cell proliferation in both the hippocampal neurogenic region and by oligodendrocyte precursors as well as changes in hormonal or growth factor levels. A number of possible treatments have been suggested which range from pharmacological interventions to cognitive behavioural therapies. Some of these have only been tested in animal models while others have produced varying degrees of improvement in patient populations. Currently, there is no recognised treatment and a greater understanding of the causes of the cognitive decline experienced after chemotherapy will be key to finding ways of preventing or treating the effects of chemobrain.

Residual memory dysfunction in recurrent major depressive disorder--a longitudinal study from Juntendo University Mood Disorder Project

BACKGROUND

Depression may increase the risk of developing Alzheimer's disease. Large cohort studies have shown that recurrent depression is associated with a risk of developing dementia. Other studies have documented smaller hippocampal volume in patients with recurrent depression. It is speculative that a greater risk of developing dementia may result from a higher number of previous depressive episodes. This study compared patients with recurrent and single-episode depression in the remitted stage, and healthy controls to elucidate the impact of the number of depressive episodes on memory.

METHODS

Logical memory and visual reproduction subtests of the Wechsler Memory Scale-Revised were given to 68 patients with major depressive disorder (MDD) (30 patients with a single episode and residual 38 patients with recurrent multiple episodes) and 57 healthy controls. The patients with MDD received memory assessment at the time of initial remission and at the follow-up period 3 years after remission.

RESULTS

At the time of initial remission, scores of both logical memory and visual reproduction subtests were significantly lower in both patient groups compared with healthy controls. At follow-up, memory dysfunction of the single-episode group disappeared, whereas scores in the recurrent group remained significantly lower than those of the single-episode group and controls.

LIMITATIONS

All patients in the present study were on antidepressant medications.

CONCLUSIONS

Patients with recurrent MDD with multiple depressive episodes showed residual memory dysfunction even after 3 years of remission. Persistence of memory deficits in the recurrent depression may be a risk factor for developing dementia.

Both chronic treatments by epothilone D and fluoxetine increase the short-term memory and differentially alter the mood status of STOP/MAP6 KO mice

Recent evidence underlines the crucial role of neuronal cytoskeleton in the pathophysiology of psychiatric diseases. In this line, the deletion of STOP/MAP6 (Stable Tubule Only Polypeptide), a microtubule-stabilizing protein, triggers various neurotransmission and behavioral defects, suggesting that STOP knockout (KO) mice could be a relevant experimental model for schizoaffective symptoms. To establish the predictive validity of such a mouse line, in which the brain serotonergic tone is dramatically imbalanced, the effects of a chronic fluoxetine treatment on the mood status of STOP KO mice were characterized. Moreover, we determined the impact, on mood, of a chronic treatment by epothilone D, a taxol-like microtubule-stabilizing compound that has previously been shown to improve the synaptic plasticity deficits of STOP KO mice. We demonstrated that chronic fluoxetine was either antidepressive and anxiolytic, or pro-depressive and anxiogenic, depending on the paradigm used to test treated mutant mice. Furthermore, control-treated STOP KO mice exhibited paradoxical behaviors, compared with their clear-cut basal mood status. Paradoxical fluoxetine effects and control-treated STOP KO behaviors could be because of their hyper-reactivity to acute and chronic stress. Interestingly, both epothilone D and fluoxetine chronic treatments improved the short-term memory of STOP KO mice. Such treatments did not affect the serotonin and norepinephrine transporter densities in cerebral areas of mice. Altogether, these data demonstrated that STOP KO mice could represent a useful model to study the relationship between cytoskeleton, mood, and stress, and to test innovative mood treatments, such as microtubule-stabilizing compounds.

Fluoxetine restores spatial learning but not accelerated forgetting in mesial temporal lobe epilepsy

Learning and memory dysfunction is the most common neuropsychological effect of mesial temporal lobe epilepsy, and because the underlying neurobiology is poorly understood, there are no pharmacological strategies to help restore memory function in these patients. We have demonstrated impairments in the acquisition of an allocentric spatial task, in patients with unilateral hippocampal sclerosis. We also show that patients have accelerated forgetting of the learned spatial task and that this is associated with damage to the non-dominant hippocampal formation. We go on to show a very similar pattern of chronic allocentric learning and accelerated forgetting in a status epilepticus model of mesial temporal lobe epilepsy in rats, which is associated with reduced and abnormal hippocampal neurogenesis. Finally, we show that reversal of the neurogenic deficit using fluoxetine is associated with reversal of the learning deficit but not the accelerated forgetting, pointing to a possible dissociation in the underlying mechanisms, as well as a potential therapeutic strategy for improving hippocampal-dependent learning in patients with mesial temporal lobe epilepsy.