Cognition in mania and depression: psychological models and clinical implications

Dysfunction of neurotransmitter metabolism is associated with the severity of depression in first-diagnosed, drug-naïve depressed patients

BACKGROUND & AIMS

Biochemical changes of neurotransmitters underlying major depressive disorder (MDD) are unknown. This study preliminarily explored the association between neurotransmitters with MDD and the possibility of objective laboratory prediction of neurotransmitter involvement in MDD.

METHODS

A total of 87 first-diagnosed, drug-naïve patients with depression and 50 healthy controls (HCs) were included in the cross-sectional study. The levels and turnovers of neurotransmitters (glutamine (GLN), glutamic acid (GLU), γ-2Aminobutiric acid (GABA), kainate (KA), vanillylmandelic acid (VMA), 3-methoxy 4-hydroxyphenyl ethylene glycol (MHPG), noradrenaline (NE), homovanillic acid (HVA), dihydroxy-phenyl acetic acid (DOPAC), dopamine (DA), tryptophane (TRP), kynurenine (KYN), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA)) were determined and the confounding factors were adjusted. Then a correlation and a predictive analysis towards neurotransmitters for MDD were performed.

RESULTS

After adjusting confounding factors, GLU (OR = 1.159), (GLU+ GABA)/GLN (OR = 1.217), DOPAC (OR = 1.106), DOPAC/DA (OR = 1.089) and (DOPAC+ HVA)/DA (OR = 1.026) enacted as risk factors of MDD, while KYN (OR = 0.992) was a protective factor. GABAergic and TRPergic pathways were associated with severity of depressive and anxiety symptoms in patients with depression. The predictive model for MDD (AUC = 0.775, 95%CI 0.683-0.860) consisted of KYN (OR = 0.990) and (GLU + GABA)/GLN (OR = 4.101).

CONCLUSIONS

First-diagnosed, drug-naïve depression patients showed abnormal neurotransmitter composition. GLU, (GLU + GABA)/GLN, DOPAC, DOPAC/DA and (DOPAC + HVA)/DA were risk factors of MDD, while KYN was a protective factor. GABAergic and TRPergic pathways were correlated with MDD clinical characteristics. KYN and (GLU + GABA)/GLN may have a predictive value for MDD.

Association of HTR3B gene polymorphisms with depression and its executive dysfunction: a case-control study

BACKGROUND

Previous studies have shown that depression was associated with HTR3B gene. The aim of this study was to investigate the relationship between polymorphisms of the HTR3B gene and depression and its executive dysfunction in Chinese Han population.

METHODS

A total of 229 patients with depressive disorder and 202 healthy controls were enrolled. Six Single nucleotide polymorphism sites (SNPs) including rs10789970, rs4938056, rs12421126, rs1176744, rs2276305 and rs12795805 were genotyped by Snapshot. Clinical features were collected using a general demographic questionnaire. The 24-item Hamilton Depression Scale (HAMD) was used to assess the symptoms' severity of the patients. The patients' executive function was assessed using a series of cognitive tests including Maze Test, Symbolic Coding Test, Spatial Span Inverse Order Test, Linking Test, and Emotional Management Test.

RESULTS

The genotypic and allelic distributions of rs1176744 in HTR3B gene were significantly different (χ² = 11.129, P = 0.004, χ² = 9.288, P = 0.002, respectively) between patients and controls. The A allele was positively correlated with depression. The proportion of A carriers was significantly higher and that of C carriers was lower in patients than those in controls. Patients had significantly lower scores of Spatial Span Inverse Order Test in carriers of A allele at locus rs1176744 and higher scores in carriers of C alleles at locus rs1176744 and rs12795805.

CONCLUSIONS

The polymorphisms of HTR3B gene may be associated with depression in Chinese Han population. The A allele of rs1176744 may increase the risk of developing depression and executive dysfunction while C alleles of rs1176744 and rs12795805 may be the protective factors for executive dysfunction in patients with depression.

Differential aberrant connectivity of precuneus and anterior insula may underpin the diagnosis of schizophrenia and mood disorders

BACKGROUND

Over the past decade, resting-state functional magnetic resonance imaging (rs-fMRI) has concentrated on brain networks such as the default mode network (DMN), the salience network (SN), and the central executive network (CEN), allowing for a better understanding of cognitive deficits observed in mental disorders, as well as other characteristic psychopathological phenomena such as thought and behavior disorganization.

AIM

To investigate differential patterns of effective connectivity across distributed brain networks involved in schizophrenia (SCH) and mood disorders.

METHODS

The sample comprised 58 patients with either paranoid syndrome in the context of SCH (n = 26) or depressive syndrome (Ds) (n = 32), in the context of major depressive disorder or bipolar disorder. The methods used include rs-fMRI and subsequent dynamic causal modeling to determine the direction and strength of connections to and from various nodes in the DMN, SN and CEN.

RESULTS

A significant excitatory connection from the dorsal anterior cingulate cortex to the anterior insula (aI) was observed in the SCH patient group, whereas inhibitory connections from the precuneus to the ventrolateral prefrontal cortex and from the aI to the precuneus were observed in the Ds group.

CONCLUSION

The results delineate specific patterns associated with SCH and Ds and offer a better explanation of the underlying mechanisms of these disorders, and inform differential diagnosis and precise treatment targeting.

Neuromolecular Underpinnings of Negative Cognitive Bias in Depression

This selective review aims to summarize the recent advances in understanding the neuromolecular underpinnings of biased cognition in depressive disorder. We begin by considering the cognitive correlates of depressed mood and the key brain systems implicated in its development. We then review the core findings across two domains of biased cognitive function in depression: pessimistic judgment bias and abnormal response to negative feedback. In considering their underlying substrates, we focus on the neurochemical mechanisms identified by genetic, molecular and pharmacological challenge studies. We conclude by discussing experimental approaches to the treatment of depression, which are derived largely from an improved understanding of its cognitive substrates.

Assessment of cognitive performances in major depressed patients: a 6-month follow-up study

OBJECTIVE

Our study aimed to assess the longitudinal change of cognitive functions in depressed patients after a 6-month interval free of mood symptoms.

METHODS

In a longitudinal study, 65 patients diagnosed with recurrent major depressive disorder were evaluated twice with neurocognitive tests, during an acute depressed episode and after 6 months of euthymia. The cognitive dimension was assessed with neuropsychological tests of attention and processing speed, memory, verbal fluency, psychomotor speed and executive functions. The severity of depression was evaluated through Hamilton Depression Rating Scale - 17 items. All the results were compared with the outcomes of 35 healthy controls, both in depression and euthymia.

RESULTS

Depressed patients compared to controls displayed significant statistical differences for most cognitive tests applied, verbal and working memory being the most severely impaired. They were still impaired at the second evaluation. Significant differences were noted between the euthymic and control group, too. Between the depression phase and euthymia, patients obtained significant improvement for attention and processing speed, verbal fluency, motor speed and executive functions.

CONCLUSIONS

Results from the current study indicate that cognitive impairment is more severe for depressed patients, decreases for euthymic subjects, and lasts longer after depressive symptoms remit.

Endophenotypical drift in Huntington's disease: a 5-year follow-up study

BACKGROUND

Huntington's disease (HD) is clinically characterized by progressing motor, cognitive and psychiatric symptoms presenting as varying phenotypes within these three major symptom domains. The disease is caused by an expanded CAG repeat tract in the huntingtin gene and the pathomechanism leading to these endophenotypes is assumed to be neurodegenerative. In 2012/2013 we recruited 107 HD gene expansion carriers (HDGECs) and examined the frequency of the three cardinal symptoms and in 2017/2018 we followed up 74 HDGECs from the same cohort to describe the symptom trajectories and individual drift between the endophenotypes as well as potential predictors of progression and remission.

RESULTS

We found higher age to reduce the probability of improving on psychiatric symptoms; increasing disease burden score ((CAG-35.5) * age) to increase the risk of developing cognitive impairment; increasing disease burden score and shorter education to increase the risk of motor onset while lower disease burden score and higher Mini Mental State Examination increased the probability of remaining asymptomatic. We found 23.5% (N = 8) to improve from their psychiatric symptoms.

CONCLUSIONS

There is no clear pattern in the development of or drift between endophenotypes. In contrast to motor and cognitive symptoms we find that psychiatric symptoms may resolve and thereby not entirely be caused by neurodegeneration. The probability of improving from psychiatric symptoms is higher in younger age and advocates for a potential importance of early treatment.

Consequences of alcohol use, and its association with psychological distress, sensitivity to emotional contagion and age of onset of alcohol use, in Uruguayan youth with or without college degree

Psychological distress can promote alcohol consumption during emerging adulthood. Still unknown is, however, how predisposition to emotional contagion alters psychological distress, and how these phenomena are affected by level of education. The present study analyzed the effect of psychological distress, age of first contact with alcohol (early, late), and predisposition to emotional contagion on alcohol-induced negative consequences and on the volume of alcohol consumed during the last year. We also described alcohol-use behaviors as a function of sex, maximum level of education and age of first contact with alcohol, in 1505 youth from Uruguay (18-30 years). A survey measured alcohol use (Alcohol Use Disorders Identification Test and ad-hoc questionnaire), negative consequences of alcohol use [young adult alcohol consequences questionnaire (YAACQ)], psychological distress (Kessler scale) and proclivity to emotional contagion (Doherty Emotional contagion scale). The patterns of alcohol use were greater in men vs. women and in those featuring an early age of first alcohol use, yet similar in college and non-college graduates. Early drinkers had greater levels of psychological distress than late-onset drinkers. There was a significant bivariate and multiple correlation between psychological distress and the number of negative consequences of alcohol experienced during the last year, which remained significant even after controlling for total volume of alcohol consumed. Significant associations emerged between YAACQ scores and frequency of heavy episodic or binge drinking, and between psychological distress and emotional contagion, but not between emotional contagion and any of the remaining variables. Psychological distress was not significantly correlated with heavy episodic or binge drinking. The study indicates that, during adolescence and youth, psychological distress is associated with experiencing negative consequences of alcohol consumption. The study also suggested that greater levels of psychological distress may underlie the facilitating effect of an early age of drinking onset upon alcohol drinking patterns.

Cognitive dysfunction in body dysmorphic disorder: new implications for nosological systems and neurobiological models

Introduction Body dysmorphic disorder (BDD) is a debilitating disorder, characterized by obsessions and compulsions relating specifically to perceived appearance, and which has been newly classified within the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Obsessive-Compulsive and Related Disorders grouping. Until now, little research has been conducted into the cognitive profile of this disorder.

METHODS

Participants with BDD (n=12) and participants without BDD (n=16) were tested using a computerized neurocognitive battery investigating attentional set-shifting (Intra/Extra Dimensional Set Shift Task), decision-making (Cambridge Gamble Task), motor response-inhibition (Stop-Signal Reaction Time Task), and affective processing (Affective Go-No Go Task). The groups were matched for age, IQ, and education.

RESULTS

In comparison to controls, patients with BDD showed significantly impaired attentional set-shifting, abnormal decision-making, impaired response inhibition, and greater omission and commission errors on the emotional processing task.

CONCLUSION

Despite the modest sample size, our results showed that individuals with BDD performed poorly compared to healthy controls on tests of cognitive flexibility, reward and motor impulsivity, and affective processing. Results from separate studies in OCD patients suggest similar cognitive dysfunction. Therefore, these findings are consistent with the reclassification of BDD alongside OCD. These data also hint at additional areas of decision-making abnormalities that might contribute specifically to the psychopathology of BDD.

Executive function impairments in depression and bipolar disorder: association with functional impairment and quality of life

BACKGROUND

The neuropsychological correlates of major depressive (MDD) and bipolar disorder (BD), and their association with quality of life (QOL) and functioning, have not been sufficiently studied in the literature. The present study aimed to compare executive functions, attention, processing speed, QOL and disability between patients with BD type I, BD type II, MDD and healthy controls.

METHOD

205 participants (n=37 BDI, 81% female; n=35 BDII, 80% female; n=45 MDD, 69% female; n=89C, 46% female) aged between 18 and 67 years were administered an extensive neurocognitive battery consisting of widely used standardized measures such as the Trail Making Test, the Stroop Color-Word Test and a modified version of the Wisconsin Card Sorting Task. Z-scores were compared between groups by ANCOVA. The prevalence of impairments on each measure (Z-score<1.5) was compared between groups using chi-square tests. The associations between cognition, quality of life and functioning were evaluated through correlational analysis.

RESULTS

Patients with MDD showed poor selective and sustained attention, and exhibited impairments in timed tasks, suggesting low efficiency of executive processing. Patients with BDI displayed more widespread cognitive impairment than the remaining groups, and performed worse than subjects with MDD on measures of sustained attention and inhibitory control. Decision-making ability and attentional control were able to distinguish between patients with BDI and BDII. QOL and disability were most impaired in patients with BDI, and more closely associated with cognitive impairment than in the remaining groups.

LIMITATIONS

No control of pharmacological variables, clinical or demographic characteristics.

CONCLUSIONS

Our results provide important information regarding the nature and severity of the cognitive alterations associated with different mood disorders, and may contribute to the diagnosis, rehabilitation and treatment of these conditions.

Optimising screening for cognitive dysfunction in bipolar disorder: Validation and evaluation of objective and subjective tools

INTRODUCTION

Cognitive impairment is common in bipolar disorder and contributes to socio-occupational difficulties. The objective was to validate and evaluate instruments to screen for and monitor cognitive impairments, and improve the understanding of the association between cognitive measures and socio-occupational capacity.

METHODS

Patients with bipolar disorder in partial or full remission (n=84) and healthy controls (n=68) were assessed with the Screen for Cognitive Impairment in Psychiatry (SCIP), Cognitive Complaints in Bipolar Disorder Rating Scale (COBRA), and established neuropsychological tests and subjective rating scales. Socio-occupational function and affective symptoms were evaluated with the Functional Assessment Short Test, and the Hamilton Depression Rating Scale 17-items and Young Mania Rating Scale, respectively. Concurrent validity of the SCIP and COBRA were assessed by correlation with established objective and subjective cognitive measures, and decision validity was determined with Receiver-Operating-Characteristic analyses. Correlations and linear regression analyses were conducted to determine the associations between objective and subjective cognitive impairment, and socio-occupational difficulties.

RESULTS

The SCIP and COBRA correlated strongly with established objective and subjective cognitive measures, respectively. The SCIP yielded higher sensitivity and specificity for detection of cognitive dysfunction than the COBRA or a combined SCIP-COBRA measure. Correlations between objective and subjective cognitive impairment were weak but both were associated with socio-occupational difficulties.

LIMITATIONS

Influence of ageing was not investigated.

CONCLUSIONS

The SCIP and COBRA are valid for detection of objective and subjective cognitive impairment in bipolar disorder. Screening for cognitive dysfunction should be conducted with an objective measure like the SCIP.

Effects of Short-Term Cognitive Remediation on Cognitive Dysfunction in Partially or Fully Remitted Individuals with Bipolar Disorder: Results of a Randomised Controlled Trial

INTRODUCTION

Cognitive dysfunction is common in bipolar disorder (BD) but is not sufficiently addressed by current treatments. Cognitive remediation (CR) may improve cognitive function in schizophrenia but no randomised controlled trial has investigated this intervention in BD. The present study aimed to investigate the effects of CR on persistent cognitive dysfunction in BD.

METHOD

Patients with BD in partial remission with cognitive complaints were randomised to 12 weeks group-based CR (n=23) or standard treatment (ST) (n=23). Outcomes were improved verbal memory (primary), sustained attention, executive and psychosocial function (secondary) and additional measures of cognitive and psychosocial function (tertiary). Participants were assessed at baseline and weeks 12 and 26.

RESULTS

Of the 46 randomised participants five dropped out and one was excluded after baseline. CR (n=18) had no effect on primary or secondary measures of cognitive or psychosocial function compared with ST (n=22). However, CR improved subjective sharpness at week 12, and quality of life and verbal fluency at week 26 follow-up (tertiary outcomes). Although the trial turned out to have suboptimal statistical power for the primary outcome analysis, calculation of the 95% confidence interval showed that it was highly unlikely that an increase in sample size would have rendered any beneficial effects of CR vs. ST on the verbal memory.

CONCLUSIONS

Short-term group-based CR did not seem to improve overall cognitive or psychosocial function in individuals with BD in full or partial remission. The present findings suggest that that longer-term, more intensive and individualised CR may be necessary to improve cognition in BD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01457235.

Cognitive-behavioral therapy induces sensorimotor and specific electrocortical changes in chronic tic and Tourette's disorder

BACKGROUND

Tic disorders, such as the Gilles de la Tourette syndrome and persistent tic disorder, are neurodevelopmental movement disorders involving impaired motor control. Hence, patients show repetitive unwanted muscular contractions in one or more parts of the body. A cognitive-behavioral therapy, with a particular emphasis on the psychophysiology of tic expression and sensorimotor activation, can reduce the frequency and intensity of tics. However, its impact on motor activation and inhibition is not fully understood.

METHODS

To study the effects of a cognitive-behavioral therapy on electrocortical activation, we recorded the event-related potentials (ERP) and lateralized readiness potentials (LRP), before and after treatment, of 20 patients with tic disorders and 20 healthy control participants (matched on age, sex and intelligence), during a stimulus-response compatibility inhibition task. The cognitive-behavioral therapy included informational, awareness training, relaxation, muscle discrimination, cognitive restructuration and relapse prevention strategies.

RESULTS

Our results revealed that prior to treatment; tic patients had delayed stimulus-locked LRP onset latency, larger response-locked LRP peak amplitude, and a frontal overactivation during stimulus inhibition processing. Both stimulus-locked LRP onset latency and response-locked LRP peak amplitude normalized after the cognitive behavioral therapy completion. However, the frontal overactivation related to inhibition remained unchanged following therapy.

CONCLUSIONS

Our results showed that P300 and reaction times are sensitive to stimulus-response compatibility, but are not related to tic symptoms. Secondly, overactivity of the frontal LPC and impulsivity in TD patients were not affected by treatment. Finally, CBT had normalizing effects on the activation of the pre-motor and motor cortex in TD patients. These results imply specific modifications of motor processes following therapy, while inhibition processes remained unchanged. Given that LRPs are partially generated within the sensorimotor and supplementary motor area, the reported reduction in tic frequency and improvements of LRPs components suggest that CBT induced a physiological change in patients' motor area.

Difference of perceptions and evaluation of cognitive dysfunction in major depressive disorder patients across psychiatrists internationally

BACKGROUND

Many studies have suggested that major depressive disorder (MDD) is often associated with cognitive dysfunction. Despite this, guidance addressing assessment of cognitive dysfunction in MDD is lacking. The aim of this study was to examine psychiatrists' perceptions and evaluation of cognitive dysfunction in routine practice in MDD patients across different countries.

METHOD

A total of 61 psychiatrists in the US, Germany, France, Spain, Hong Kong, and Australia participated in an online survey about perceptions of cognitive dysfunction in MDD patients, evaluation of cognition and instruments used in cognitive evaluation.

RESULTS

Most psychiatrists reportedly relied on patient history interviews for cognitive evaluation (83% in France and approximately 60% in the USA, Germany, Australia and Hong Kong). The remainder used a cognitive instrument or a combination of cognitive instrument and patient history interview for assessment. Of those using instruments for cognitive assessment, only nine named instruments that were appropriate for cognitive evaluation. The remainder reported other clinical measures not intended for cognitive evaluation.

CONCLUSIONS

Overall, psychiatrists in routine clinical practice value the assessment of cognitive in MDD. However, there is a lack of standardization in these assessments and misconceptions regarding proper assessment.

Effects of cognitive remediation on cognitive dysfunction in partially or fully remitted patients with bipolar disorder: study protocol for a randomized controlled trial

BACKGROUND

A large proportion of patients with bipolar disorder experience persistent cognitive dysfunction, such as memory, attention and planning difficulties, even during periods of full remission. The aim of this trial is to investigate whether cognitive remediation, a new psychological treatment, improves cognitive function and, in turn, psychosocial function in patients with bipolar disorder in partial or full remission.

METHODS/DESIGN

The trial has an evaluator-blind, randomized, between-groups design. Forty patients with bipolar disorder in full or partial remission, aged 18 to 50 years, who report moderate to severe cognitive difficulties, are recruited. Patients are randomized to receive weekly group-based cognitive remediation treatment over 12 weeks in addition to standard treatment or standard treatment alone. Both groups undergo neurocognitive testing and functional magnetic resonance imaging (fMRI) at baseline, post-treatment (week 12) and follow-up (week 26). The primary outcome is improved verbal memory, as measured with the Rey Auditory Verbal Learning Test (RAVLT) from baseline to post-treatment. With inclusion of 40 patients we obtain 86% power to detect a clinically relevant difference in verbal memory between groups. Secondary outcomes are improved attention, executive function and psychosocial function, as measured with the Rapid Visual Information Processing test, the Trail Making Test part B and the Functional Assessment Short Test (FAST), respectively. Tertiary outcomes are improved scores for additional neuropsychological tests of memory, attention, executive function and facial expression recognition, as well as in questionnaires measuring subjective cognitive difficulties, stress, coping strategies, personality traits, depressive symptoms and quality of life.

DISCUSSION

This is the first randomized controlled trial to evaluate the effects of cognitive remediation on cognitive function in patients with bipolar disorder who experience persistent cognitive difficulties despite being in full or partial remission.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01457235.

Is there an association between subjective and objective measures of cognitive function in patients with affective disorders?

BACKGROUND

Patients with affective disorders experience cognitive dysfunction in addition to their affective symptoms. The relationship between subjectively experienced and objectively measured cognitive function is controversial with several studies reporting no correlation between subjective and objective deficits.

AIMS

To investigate whether there is a correlation between subjectively reported and objectively measured cognitive function in patients with affective disorders, and whether subjective complaints predict objectively measured dysfunction.

METHODS

The study included 45 participants; 15 with bipolar disorder (BD), 15 with unipolar disorder (UD) and 15 healthy individuals. Participants' subjectively experienced cognitive function and objective cognitive function were assessed with the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (CPFQ) and the Screen for Cognitive Impairment in Psychiatry (SCIP), respectively. Patients were rated for affective symptoms with Hamilton Depression Rating Scale (HDRS) and Young Mania Rating Scale (YMRS).

RESULTS

Patients demonstrated subjective and objective cognitive dysfunction relative to controls (P-values ≤ 0.01) but there were no differences between patient groups (P > 0.1). We found no correlation between subjectively experienced and objectively measured cognitive dysfunction in BD (P = 0.7), and a non-significant trend towards a correlation in UD (P = 0.06), which disappeared when controlling for gender (P = 0.1).

CONCLUSION

Our results suggest that it is not necessarily patients who have cognitive complaints that are most impaired. If confirmed in a larger sample, our findings suggest that neuropsychological assessment is warranted to elucidate the potential role of cognitive dysfunction in patients' everyday lives and to inform treatment strategies targeting these difficulties.

The role of clinical variables, neuropsychological performance and SLC6A4 and COMT gene polymorphisms on the prediction of early response to fluoxetine in major depressive disorder

INTRODUCTION

Major depressive disorder (MDD) is treated with antidepressants, but only between 50% and 70% of the patients respond to the initial treatment. Several authors suggested different factors that could predict antidepressant response, including clinical, psychophysiological, neuropsychological, neuroimaging, and genetic variables. However, these different predictors present poor prognostic sensitivity and specificity by themselves. The aim of our work is to study the possible role of clinical variables, neuropsychological performance, and the 5HTTLPR, rs25531, and val108/58Met COMT polymorphisms in the prediction of the response to fluoxetine after 4weeks of treatment in a sample of patient with MDD.

METHODS

64 patients with MDD were genotyped according to the above-mentioned polymorphisms, and were clinically and neuropsychologically assessed before a 4-week fluoxetine treatment. Fluoxetine response was assessed by using the Hamilton Depression Rating Scale. We carried out a binary logistic regression model for the potential predictive variables.

RESULTS

Out of the clinical variables studied, only the number of anxiety disorders comorbid with MDD have predicted a poor response to the treatment. A combination of a good performance in variables of attention and low performance in planning could predict a good response to fluoxetine in patients with MDD. None of the genetic variables studied had predictive value in our model.

LIMITATIONS

The possible placebo effect has not been controlled. Our study is focused on response prediction but not in remission prediction.

CONCLUSIONS

Our work suggests that the combination of the number of comorbid anxiety disorders, an attentional variable, and two planning variables makes it possible to correctly classify 82% of the depressed patients who responded to the treatment with fluoxetine, and 74% of the patients who did not respond to that treatment.

Effects of erythropoietin on depressive symptoms and neurocognitive deficits in depression and bipolar disorder

Background

Depression and bipolar disorder are associated with reduced neural plasticity and deficits in memory, attention and executive function. Drug treatments for these affective disorders have insufficient clinical effects in a large group and fail to reverse cognitive deficits. There is thus a need for more effective treatments which aid cognitive function. Erythropoietin (Epo) is involved in neuroplasticity and is a candidate for future treatment of affective disorders. The investigators have demonstrated that a single dose of Epo improves cognitive function and reduces neurocognitive processing of negative emotional information in healthy and depressed individuals similar to effects seen with conventional antidepressants. The current study adds to the previous findings by investigating whether repeated Epo administration has antidepressant effects in patients with treatment resistant depression and reverses cognitive impairments in these patients and in patients with bipolar disorder in remission.

Methods/design

The trial has a double-blind, placebo-controlled, parallel-group design. 40 patients with treatment-resistant major depression and 40 patients with bipolar disorder in remission are recruited and randomised to receive weekly infusions of Epo (Eprex; 40,000 IU) or saline (NaCl 0.9%) for 8 weeks. Randomisation is stratified for age and gender. The primary outcome parameters for the two studies are: depression severity measured with the Hamilton Depression Rating Scale 17 items (HDRS-17) [1] in study 1 and, in study 2, verbal memory measured with the Rey Auditory Verbal Learning Test (RAVLT) [2,3]. With inclusion of 40 patients in each study we obtain 86% power to detect clinically relevant differences between intervention and placebo groups on these primary outcomes.

Trial registration

The trial is approved by the Local Ethics Committee: H-C-2008-092, Danish Medicines Agency: 2612-4020, EudraCT: 2008-04857-14, Danish Data Agency: 2008-41-2711 and ClinicalTrials.gov: NCT 00916552.

Major Depressive Disorder in recovery and neuropsychological functioning: effects of selective serotonin reuptake inhibitor and dual inhibitor depression treatments on residual cognitive deficits in patients with Major Depressive Disorder in recovery

INTRODUCTION

Cognitive disturbances in Major Depressive Disorder (MDD) could persist beyond the symptomatic phase of the illness. However, the works addressing this topic did not usually account for the possible impact of medication on the cognitive functions of depressed patients. The present study aims to investigate whether MDD patients in remission treated with selective serotonin reuptake inhibitors (SSRI) or dual serotonergic-noradrenergic reuptake inhibitors (SNRI) show cognitive deficits, to study whether the same patients suffer neuropsychological disturbances when they are unmedicated and in recovery phase, and if the previous pharmacological treatment used to achieve the remission of MDD clinical symptoms had any effect in the profile of these patients' cognitive performance in the recovery phase.

METHODS

Thirty-six subjects with MDD treated with escitalopram and 37 depressed patients with duloxetine were compared both in remission phase and 24 weeks later, when they were unmedicated and in recovery phase. They were also compared, in both moments, to 37 healthy subjects.

RESULTS

The control subjects showed a broader better cognitive performance than MDD patients in both measurement moments, but several cognitive functions improved over time. Also, the patients treated with SNRI performed better in memory tests than the SNRI-treated patients in remission phase, and in recovery phase.

LIMITATIONS

Our sample size is somewhat small, and we followed our patients only for 6months after treatment.

CONCLUSIONS

Cognitive functions improve over time in patients with MDD beyond the remission phase, and the antidepressant treatment class used in acute depressive phase could influence his/her memory improvement.

Effects of selective serotonin reuptake and dual serotonergic-noradrenergic reuptake treatments on attention and executive functions in patients with major depressive disorder

Several reports suggest that antidepressants may improve cognitive functioning in patients with major depressive disorder (MDD). The present work aims to study the effects of selective serotonin reuptake inhibitors (SSRIs) and serotonergic-noradrenergic reuptake inhibitors (SNRIs) treatments on the performance of working memory, attention and executive functions in patients with MDD. A total of 73 subjects meeting the Diagnostic and Statistical Manual of Mental Disorders version IV (DSM-IV) criteria for MDD, and 37 control subjects were assessed with the Hamilton Depression Rating Scale and a neuropsychological battery. The subjects were medicated with escitalopram (n=36) or duloxetine (n=37) for 24 weeks. At the end of the trial, the subjects were assessed again with the same tests. The depressed subjects showed alterations in attention and cognitive functions when compared to the control group. The administration of both treatments improved working memory, as well as attention and all the executive functions, but the cognitive functions of depressed patients do not improve enough to reach the levels of performance of the control subjects. Our results suggest that both SSRI and SNRI treatments presented the same efficacy in improving attention and the remaining executive functions.

Inhibition of thoughts and actions in obsessive-compulsive disorder: extending the endophenotype?

BACKGROUND

Obsessive-compulsive disorder (OCD) has been associated with impairments in stop-signal inhibition, a measure of motor response suppression. The study used a novel paradigm to examine both thought suppression and response inhibition in OCD, where the modulatory effects of stimuli relevant to OCD could also be assessed. Additionally, the study compared inhibitory impairments in OCD patients with and without co-morbid depression, as depression is the major co-morbidity of OCD.

METHOD

Volitional response suppression and unintentional thought suppression to emotive and neutral stimuli were examined using a novel thought stop-signal task. The thought stop-signal task was administered to non-depressed OCD patients, depressed OCD patients and healthy controls (n=20 per group).

RESULTS

Motor inhibition impairments were evident in OCD patients, while motor response performance did not differ between patients and controls. Switching to a new response but not motor inhibition was affected by stimulus relevance in OCD patients. Additionally, unintentional thought suppression as measured by repetition priming was intact. OCD patients with and without depression did not differ on any task performance measures, though there were significant differences in all self-reported measures.

CONCLUSIONS

Results support motor inhibition deficits in OCD that remain stable regardless of stimulus meaning or co-morbid depression. Only switching to a new response was influenced by stimulus meaning. When response inhibition was successful in OCD patients, so was the unintentional suppression of the accompanying thought.

Cognitive deficits in the euthymic phase of unipolar depression

Although neuropsychological deficits have been reported in patients with major depressive disorder (MDD) during an acute episode, relatively little is known about the persistence of these deficits in remission. This study investigated the performance of attention, executive function and verbal memory during remission from unipolar depressive episodes. We tested the hypothesis that outpatients do not differ in cognitive variables from controls. We did this using a well-defined outpatient sample, consisting of medicated and unmedicated patients, with a history of MDD. Ninety-seven subjects with MDD in remission ranging from young to old were compared with 97 healthy control subjects. Both samples were balanced for age, gender, and education levels. The Auditory Verbal Learning Test (AVLT) and the Trail Making Test (TMT) were used. Patients with remitted MDD, in comparison with controls, were impaired on tasks of attention, executive function and verbal memory. The individual level of depressive symptoms was not related to the cognitive performance. Small- to medium-sized significant correlations exist between cognitive test variables (as represented by Trail Making B and AVLT delayed recall) and level of depressive symptomatology (as measured by MADRS or BDI-II) in the total sample, indicating that higher levels of depressive symptomatology are associated with lower cognitive function. These findings suggest deficits in attention and delayed verbal recall can serve as an indicator for MDD in outpatients.

Effects of selective serotonin reuptake and dual serotonergic-noradrenergic reuptake treatments on memory and mental processing speed in patients with major depressive disorder

Patients with major depressive disorder (MDD) usually suffer from altered cognitive functions of episodic memory, working memory, mental processing speed and motor response. Diverse studies suggest that different antidepressant agents may improve cognitive functions in patients with MDD. The aim of this work is to study the effects of serotonergic reuptake inhibitors (SSRIs) and serotonergic-noradrenergic reuptake inhibitors (SNRIs) treatments to improve the performance on memory tasks and mental processing speed in MDD. Seventy-three subjects meeting criteria for major depressive disorder were assessed with the Hamilton depression rating scale and a neuropsychological battery. The subjects were medicated with escitalopram (n=36) or duloxetine (n=37) for 24 weeks. At the end of the trial, the subjects were assessed again with the same neuropsychological battery used prior to the treatment. Both treatments improved importantly the episodic memory and to a lesser extent, working memory, mental processing speed and motor performance. Our results suggest that cognition is partially independent from improvement in clinical symptoms. Both groups achieved remission rates in the HAM-D-17 after 24 weeks of treatment, but SNRI was superior to SSRI at improving episodic and working memory. Our work indicates that the superiority of SNRI over the SSRI at episodic memory improvement is clinically relevant.

Trichotillomania: neurobiology and treatment

Trichotillomania is a disorder characterized by repetitive hair pulling, leading to noticeable hair loss and functional impairment. This paper provides an overview of what is known of trichotillomania from several perspectives. We begin by considering historical descriptions of hair pulling that ultimately contributed to the inclusion of trichotillomania as a formal diagnostic entity in the Diagnostic and Statistical Manual. Psychological factors involved in the mediation of symptoms are examined, including positive and negative reinforcement. The relationships between trichotillomania, other body-focused repetitive behaviours, and disorders of the putative obsessive-compulsive (OC) spectrum are surveyed. The review then explores findings from the available controlled treatment trials that utilized psychotherapy, pharmacotherapy, or both. Neural circuitry involved in the manifestation of hair pulling is then identified by considering data from animal models of the condition, along with neurocognitive and neuroimaging results from patients. Finally, we highlight important areas for future neurobiological and treatment research.

Atomoxetine increases salivary cortisol in healthy volunteers

It has been proposed that acute hypothalamo-pituitary-adrenal (HPA) axis challenge using noradrenergic drugs may be of utility in assessing the functional integrity of central noradrenaline pathways. Atomoxetine (formerly tomoxetine) is a highly selective noradrenaline reuptake inhibitor, which has recently been licensed for the treatment of attention deficit hyperactivity disorder (ADHD). The aim of this study was to assess the effects of acute atomoxetine on salivary cortisol levels for the first time.A total of 60 healthy male volunteers received 60 mg atomoxetine, 30 mg citalopram, or placebo per os in a double-blind parallel groups design (n = 20 per group). Salivary cortisol, blood pressure and pulse rates were recorded at baseline and at +1.0, +1.5, +2.5 and +3.5 hours after capsule administration.60 mg atomoxetine led to highly significant increases in salivary cortisol and a moderate increase in pulse rate, in the absence of significant effects on blood pressure. 30 mg citalopram had no significant effects on cortisol or cardiovascular parameters. These data support the utility of atomoxetine neuroendocrine challenge for evaluating central noradrenaline pathways, which may be of future use in neuropsychiatric patient studies. Furthermore, the effects of atomoxetine on HPA axis function may have clinical implications given the use of this agent in the treatment of ADHD.

Stimulation of subterritories of the subthalamic nucleus reveals its role in the integration of the emotional and motor aspects of behavior

Two parkinsonian patients who experienced transient hypomanic states when the subthalamic nucleus (STN) was stimulated during postoperative adjustment of the electrical parameters for antiparkinsonian therapy agreed to have the mood disorder reproduced, in conjunction with motor, cognitive, and behavioral evaluations and concomitant functional neuroimaging. During the experiment, STN stimulation again induced a hypomanic state concomitant with activation of cortical and thalamic regions known to process limbic and associative information. This observation suggests that the STN plays a role in the control of a complex behavior that includes emotional as well as cognitive and motor components. The localization of the four contacts of the quadripolar electrode was determined precisely with an interactive brain atlas. The results showed that (i) the hypomanic state was caused only by stimulation through one contact localized in the anteromedial STN; (ii) both this contact and the contact immediately dorsal to it improved the parkinsonian motor state; (iii) the most dorsal and ventral contacts, located at the boundaries of the STN, neither induced the behavioral disorder nor improved motor performance. Detailed analysis of these data led us to consider a model in which the three functional modalities, emotional, cognitive, and motor, are not processed in a segregated manner but can be subtly combined in the small volume of the STN. This nucleus would thus serve as a nexus that integrates the motor, cognitive, and emotional components of behavior and might consequently be an effective target for the treatment of behavioral disorders that combine emotional, cognitive, and motor impairment.

Neuropsychological impairment in major depression: its nature, origin and clinical significance

Neuropsychological impairment is well established as a feature of major depressive disorder (MDD) but studies have shown a variable pattern of impairment. This paper seeks first to clarify this by examining methodological and clinical factors that give rise to variability in study findings. Second, it examines theories of the origin of these neuropsychological abnormalities. Third, it reviews evidence regarding the clinical significance of different patterns of deficit. A selective review was undertaken of the literature with a particular emphasis on methodological factors, the influence of clinical subtypes and prevalent theories of neuropsychological abnormality. Methodological issues and the heterogeneity of MDD account for considerable variability in results. Specific investigation of the subtypes of psychotic MDD, melancholic MDD and bipolar depression reduces this heterogeneity and results are more consistent in the elderly. Hypothalamic-pituitary-adrenal axis dysfunction is associated with neuropsychological dysfunction in MDD although evidence of direct causation is not definitive at present. Impairment of executive and psychomotor function is a consistent finding, particularly in the elderly, and may reflect frontostriatal-limbic dysfunction. There is growing evidence that this may have clinical significance. It is suggested that future research take very careful account of the exact phenotype of MDD. Classification based on neuropsychological profile may, in fact, be useful. Further research should examine further the clinical importance of patterns of neuropsychological impairment.

The neuropsychology of mood disorders

Cognitive dysfunction is central to our understanding of mood disorders in terms of patient experiences, Diagnostic and Statistical Manual of Mental Disorders criteria, and psychological models. In this article, we highlight key findings from studies that have used neuropsychological tests and functional neuroimaging techniques to explore cognitive dysfunction in patients with depression and mania. In particular, we focus on affective processing bias, abnormal response to negative feedback, and decision making. Results are discussed in the context of current conceptualizations of dysfunctional neural circuitry, and in relation to important clinical research implications.

Neurocognitive deficits and disability in major depressive disorder

Disability in life functioning is an important and poorly understood consequence of major depressive disorder (MDD). Mood symptoms do not account for the magnitude of disability resulting from MDD. Impairments in several domains of neurocognitive (NC) functioning have been shown to interfere with functionality in other psychiatric populations. These deficits, also present in MDD, may play a significant role in disability experienced by many with this disorder. The aim of this study was to examine the degree to which NC deficits, independent of affective and psychotic symptoms, explain functional outcome 6 months following hospitalization for a major depressive episode. Participants with an MDD diagnosis (N=48) received NC testing and symptom ratings while in the hospital. These procedures were repeated, along with functionality ratings, 6 months later. Six-month NC performance was strongly associated with functionality ratings after covariation for residual depression. Selected NC domains tested at baseline were predictive of functionality at 6 months. These data indicate that NC deficits, at least for some MDD sufferers, play an important role in functional recovery. New treatments, whether pharmacologic or rehabilitative, may be required to help affected patients accommodate neurocognitively based performance deficits at work, at home and in the community.

Noradrenergic modulation of working memory and emotional memory in humans

RATIONALE

Noradrenaline (NA) is implicated in arousal. Working memory is dependent upon prefrontal cortex, and moderate levels of NA are thought to facilitate working memory whereas higher levels during extreme stress may impair working memory and engage more posterior cortical and sub-cortical circuitry. The NA system also influences emotional memory via modulation of the amygdalae and related mediotemporal structures. NA dysfunction and abnormalities in arousal-dependent memory functions are evident in a variety of neuropsychiatric illnesses.

OBJECTIVES

The authors provide a concise overview of pharmacological studies that have investigated effects of selective NA manipulations on working memory and emotional memory functions in healthy human volunteers.

MATERIALS AND METHODS

Selection of relevant peer-reviewed publications was based on a PubMed search.

RESULTS

Studies to date indicate that: (1) the beta-blocker propranolol impaired working and emotional memory, (2) clonidine frequently impaired working memory, and (3) reboxetine, a selective noradrenaline reuptake inhibitor, enhanced emotional memory for positive material.

CONCLUSIONS

Improved understanding of coupling between NA, cortico-subcortical circuitry and human mnemonic functions will suggest novel therapeutic directions for the treatment of neuropsychiatric conditions, such as attention deficit hyperactivity disorder and post-traumatic stress disorder. Future research directions are discussed in relation to neuroimaging techniques, functional central nervous system polymorphisms and study designs.

Neurochemical modulation of response inhibition and probabilistic learning in humans

Cognitive functions dependent on the prefrontal cortex, such as the ability to suppress behavior (response inhibition) and to learn from complex feedback (probabilistic learning), play critical roles in activities of daily life. To what extent do different neurochemical systems modulate these two cognitive functions? Here, using stop-signal and probabilistic learning tasks, we show a double dissociation for the involvement of noradrenaline and serotonin in human cognition. In healthy volunteers, inhibition of central noradrenaline reuptake improved response inhibition but had no effect on probabilistic learning, whereas inhibition of central serotonin reuptake impaired probabilistic learning with no effect on response inhibition.

The neuropsychology of obsessive compulsive disorder: the importance of failures in cognitive and behavioural inhibition as candidate endophenotypic markers

Obsessive compulsive disorder (OCD) is a highly debilitating neuropsychiatric condition with estimated lifetime prevalence of 2-3%, more than twice that of schizophrenia. However, in contrast to other neuropsychiatric conditions of a comparable or lesser prevalence, relatively little is understood about the aetiology, neural substrates and cognitive profile of OCD. Despite strong evidence for OCD being familial, with risk to first-degree relatives much greater than for the background population, its genetic underpinnings have not yet been adequately delineated. Although cognitive dysfunction is evident in the everyday behaviour of OCD sufferers and is central to contemporary psychological models, theory-based studies of neurocognitive function have yet to reveal a reliable cognitive signature, and interpretation has often been confounded by failures to control for co-morbidities. The neuroimaging findings in OCD are amongst the most robust reported in the psychiatric literature, with structural and functional abnormalities frequently reported in orbitofrontal cortex, anterior cingulate cortex, and caudate nucleus. In spite of this, our relative lack of understanding of OCD neurochemical processes continues to impede progress in the development of novel pharmacological treatment approaches. Integrating the neurobiological, cognitive, and clinical findings, we propose that OCD might usefully be conceptualised in terms of lateral orbitofrontal loop dysfunction, and that failures in cognitive and behavioural inhibitory processes appear to underlie many of the symptoms and neurocognitive findings. We highlight existing limitations in the literature, and the potential utility of endophenotypes in overcoming these limitations. We propose that neurocognitive indices of inhibitory functions may represent a useful heuristic in the search for endophenotypes in OCD. This has direct implications not only for OCD but also for putative obsessive-compulsive spectrum conditions including attention deficit hyperactivity disorder, Tourette's syndrome, and trichotillomania (compulsive hair pulling).