The difference in patterns of motor and cognitive function in chronic fatigue syndrome and severe depressive illness

BACKGROUND: Chronic fatigue syndrome (CFS) and major depressive disorder (MDD) share many symptoms and aetiological factors but may have different neurobiological underpinnings. We wished to determine the profile of the biological variables disturbed in CFS and MDD, and identify any critical factors that differentiate the disorders. METHODS: Thirty patients with CFS, 20 with MDD and 15 healthy controls matched group-wise for age and sex were recruited. Subjects were given a detailed battery of motor and cognitive tests, including measures of psychomotor speed, memory and maximal voluntary muscle contraction in both the morning and evening that were balanced to avoid order effects. RESULTS: CFS patients generally performed worse on cognitive tests than healthy controls, but better than patients with MDD. Both patient groups had markedly impaired motor function compared with healthy controls. MDD subjects showed a significantly greater diurnal improvement in maximal voluntary contraction than healthy controls. CONCLUSIONS: Patients with CFS and MDD show similarly substantial motor impairment, but cognitive deficits are generally more marked in MDD. Diurnal changes in some functions in MDD may differentiate the disorder from CFS.     

Cognitive functioning in young and middle-aged unmedicated out-patients with major depression: testing the effort and cognitive speed hypotheses

BACKGROUND: Cognitive deficits are common in major depressive disorder, but their nature is unclear. The effort hypothesis states that performance on effortful tasks is disproportionately impaired compared with the performance on automatic tasks. The cognitive speed hypothesis states that depression is characterized by cognitive slowness, which is a source of cognitive dysfunctioning. The present study investigated both theories in unmedicated adult depressive patients. It was also investigated whether the cognitive deficits can be attributed to more general physical illness-related factors or specifically to depressive disorder. METHOD: Thirty non-psychotic depressive out-patients were compared with 38 healthy control subjects and 25 patients with severe allergic rhinitis. The effects of group on more automatic and more effortful aspects of cognitive tasks measuring cognitive speed (Concept Shifting Task, Stroop Colour Word Test, Memory Scanning Test) and memory retrieval (Visual Verbal Learning Task, Verbal Fluency Test) were evaluated by MANCOVA. Age, sex, education and pre-morbid intelligence were treated as covariates. RESULTS: The depressive group had cognitive deficits in the automatic processing subtask of the Stroop, memory scanning and memory span. Performance on more effortful tasks was not impaired. CONCLUSIONS: Our results are more consistent with the cognitive speed hypothesis. Cognitive functioning in depressive disorder seems to be characterized by a reduced speed of information processing in automatic subtasks.     

Successful computer-assisted cognitive remediation therapy in patients with unipolar depression: a proof of principle study

BACKGROUND: Despite increasing awareness of the extent and severity of cognitive deficits in major depressive disorder (MDD), trials of cognitive remediation have not been conducted. We conducted a 10-week course of cognitive remediation in patients with long-term MDD to probe whether deficits in four targeted cognitive domains, (i) memory, (ii) attention, (iii) executive functioning and (iv) psychomotor speed, could be improved by this intervention. METHOD: We administered a computerized cognitive retraining package (PSSCogReHab) with demonstrated efficacy to 12 stable patients with recurrent MDD. Twelve matched patients with MDD and a group of healthy control participants were included for comparison; neither comparator group received the intervention that involved stimulation of cognitive functions through targeted, repetitive exercises in each domain. RESULTS: Patients who received cognitive training improved on a range of neuropsychological tests targeting attention, verbal learning and memory, psychomotor speed and executive function. This improvement exceeded that observed over the same time period in a group of matched comparisons. There was no change in depressive symptom scores over the course of the trial, thus improvement in cognitive performance occurred independent of other illness variables. CONCLUSIONS: These results provide preliminary evidence that improvement of cognitive functions through targeted, repetitive exercises is a viable method of cognitive remediation in patients with recurrent MDD.     

A model of verbal memory impairments in schizophrenia: two systems and their associations with underlying cognitive processes and clinical symptoms

BACKGROUND: In a broad cognitive study of schizophrenia we investigated the relationships of verbal memory impairments with cognitive underpinnings on the one hand, and clinical symptomatology on the other. The results have been reported in previous papers. In this paper we show how all these data could be integrated into a consistent pattern of associations. METHOD: Fifty schizophrenic patients underwent a cognitive battery including a verbal memory task with free recall and recognition, a source memory task, and tests of processing speed and selective attention. Ratings for positive, negative and depressive symptoms were available for 40 of the patients. RESULTS: A factorial analysis revealed a distinction between measures of memory efficiency and measures of memory errors. The system of memory efficiency was associated with processing speed and selective attention at the cognitive level, and with depression at the symptom level. The system of memory errors was assumed to be underlain by source-monitoring deficits. These memory errors were increased by positive symptoms and decreased by certain negative symptoms. CONCLUSIONS: All the measures drawn from various memory tasks could be integrated into a model describing their associations with cognitive underpinnings and clinical symptomatology. This model provides a heuristic for the cognitive and pharmacological treatments of verbal memory impairments in schizophrenia, as well as for the understanding of positive symptoms.     

Tobacco usage interacts with postdisaster psychopathology on circadian salivary cortisol.

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) have been associated with increased rates of tobacco usage as well as with dysregulations of the hypothalamus-pituitary-adrenal (HPA) axis. At the same time tobacco also affects the HPA axis. This paper examines the relationships between PTSD, posttraumatic MDD, smoking and levels of circadian cortisol 2-3 years postdisaster. Subjects were survivors of the Enschede fireworks disaster. The sample consisted of 38 healthy survivors, 40 subjects with PTSD, and 17 subjects with posttraumatic MDD. The Composite International Diagnostic Interview was used to determine mental disorders in accordance with DSM-IV criteria. Salivary cortisol samples were collected at home immediately upon awakening, 30 min after awakening, at noon, and at 10 p.m. Quantity of smoking was measured through self-report. The results of the study show that salivary cortisol concentrations were higher in smoking subjects. Survivors with MDD following the disaster had a flatter diurnal cortisol curve than subjects with PTSD or healthy survivors. In survivors with PTSD and healthy individuals the usual dynamic pattern of increase in cortisol past awakening was present, while we did not observe this in posttraumatic MDD. These survivors with MDD tended to use more tobacco per day, and the cortisol group differences could only be revealed when we adjusted for quantity of smoking. Smoking, which may be an important palliative coping style in dealing with posttraumatic arousal symptoms, seems to mediate the relationship between traumatic stress and the HPA-axis.     

Memory complaints; the association with psycho-affective and health problems and the role of personality characteristics. A 6-year follow-up study

BACKGROUND: The objective is to investigate whether memory complaints in older persons without manifest cognitive decline are associated with depressive symptoms, anxiety symptoms, physical health and personality characteristics. Furthermore, it is investigated whether personality characteristics have a modifying effect on the association of memory complaints with depressive and anxiety symptoms and physical health. METHODS: The study was carried out using the Longitudinal Aging Study Amsterdam (LASA). Participants were examined during three observation cycles covering a period of 6 years. They were asked about memory complaints, and were examined on cognitive functioning, physical health, depressive and anxiety symptoms, and the personality characteristics: mastery, perceived self-efficacy and neuroticism. The data were analysed by means of Generalised Estimating Equations (GEE). RESULTS: Memory complaints were associated with physical health problems, depressive and anxiety symptoms, low feelings of mastery, low perceived self-efficacy and high neuroticism. The associations between memory complaints and physical health problems, depressive and anxiety symptoms were significantly stronger in people with high mastery, high perceived self-efficacy and low neuroticism. LIMITATIONS: We used a conservative criterion for cognitive decline and therefore we might have included some people with cognitive decline during our follow-up. In order to minimise selection bias we included actual cognitive performance in our regression models. CONCLUSIONS: Our findings suggest that when older persons complain about their memory and do not show actual cognitive decline, one should be aware that these complaints might reflect psycho-affective or health problems.     

Neuroendocrine and immune markers of maternal stress during pregnancy and infant cognitive development

Antenatal exposure to maternal stress is a factor that may impact on offspring cognitive development. While some evidence exists of an association between maternal antenatal depressive or anxiety symptoms and infants' cognitive outcomes, less is known about the role of biological indices of maternal antenatal stress in relation to infant cognitive development. The current study investigated the association between maternal depressive and anxiety symptoms, stress and inflammatory markers during pregnancy and infant's cognitive development in a sample of 104 healthy pregnant women (mean gestational age = 34.76; SD = 1.12) and their 12-week-old infants (mean postnatal weeks = 11.96; SD = 1.85). Maternal depressive and anxiety symptoms were evaluated during pregnancy, alongside measurements of serum Interleukin-6 (IL-6), C-Reactive Protein (CRP), salivary cortisol, and alpha amylase (sAA) concentrations. Infant cognitive development, maternal caregiving and concurrent anxiety or depressive symptoms were assessed 12 weeks after delivery. Hierarchical linear regressions indicated that higher maternal diurnal cortisol and CRP levels were independently associated with lower infant cognitive development scores, while adjusting for infant gender and gestational age, maternal IQ, caregiving, depressive, or anxiety symptoms. Though correlational, findings seem suggestive of a role for variation in maternal biological stress signals during pregnancy in influencing infants' early cognitive development.     

Categoric overgeneral autobiographical memory in adolescents with major depressive disorder

BACKGROUND: Categoric, overgeneral autobiographical memory is more common in depressed adults than controls and predicts persistence of depression. This cross-sectional study investigated whether, compared with non-depressed psychiatric cases and community controls, first episode major depressive disorder (MDD) in adolescents is associated with categoric overgeneral memory retrieval. METHODS: Ninety-six clinically referred adolescents (aged 12-17 years) with MDD, 26 non-depressed psychiatric cases and a sample of 33 community controls were recruited. All subjects were assessed using the Kiddie-Schedule for Schizophrenia and Affective Disorders, and completed Williams' cued Autobiographical Memory Test and the Mood and Feelings Questionnaire. Hamilton Depression Rating Scales were completed with MDD subjects, as an index of depression severity. RESULTS: Adolescents with current first episode MDD retrieved more categoric overgeneral memories than controls, but not than non-depressed psychiatric cases. Adolescents in full remission from a recent episode of MDD retrieved more categoric memories to positive cues than controls. Categoric memory in MDD was related to observer-rated and self-reported severity, but not to the pattern of co-morbid diagnoses. There were negative correlations between IQ and categoric memories in both clinical cases and controls. A positive correlation between categoric memory to negative cues and self-reported depressive symptoms was found in clinical cases (but not controls). CONCLUSIONS: In adolescents, increased categoric overgeneral memory is associated with, but not specific to first episode MDD. Positive categoric memories are also increased in fully remitted MDD as compared to controls.     

Pituitary-adrenal function in adolescent psychiatric patients: impact of depressive symptoms

BACKGROUND: The aim of this study was to determine whether depressive symptoms affect pituitary-adrenal function in adolescents, as they do in adults. METHODS: Salivary cortisol was measured before and after physical exercise in 23 hospitalized adolescent psychiatric patients and 13 age- and sex-matched healthy controls in a placebo-controlled design. In patients, cortisol profiles were assessed from 08:00 to 20:00 h before and after administration of low doses of dexamethasone or the natural steroid hydrocortisone. Patients were classified according to DSM III-R criteria and assigned to either a depressed group (n=10) or a non-depressed group (n=13). Subjective depressive symptoms were rated with the 90-item symptom checklist. RESULTS: Physical exercise increased cortisol output significantly in all subjects, but there were no differences between groups. In patients, no differences in basal cortisol levels were found between the depressed and non-depressed groups. Dexamethasone, but not hydrocortisone, was able to suppress cortisol levels in both groups. Differences between groups were only found in total cortisol output over the 3 days when data were analyzed according to the patients 'subjective' feelings of depression, with the highest cortisol levels in the 'subjectively more depressed' patients. CONCLUSIONS: The results obtained only partially support the hypothesis that depressive symptoms in adolescent psychiatric patients determine pituitary-adrenal (mal)function, and appear to depend on the strategy used.     

Association between major depressive symptoms in heart failure and impaired regional cerebral blood flow in the medial temporal region: a study using 99m Tc-HMPAO single photon emission computerized tomography (SPECT)

BACKGROUND AND PURPOSE: Depressive symptoms are frequently associated with heart failure (HF), but the brain mechanisms underlying such association are unclear. We hypothesized that the presence of major depressive disorder (MDD) emerging after the onset of HF would be associated with regional cerebral blood flow (rCBF) abnormalities in medial temporal regions previously implicated in primary MDD, namely the hippocampus and parahippocampal gyrus. METHOD: Using 99mTc-SPECT, we measured rCBF in 17 elderly MDD-HF patients, 17 non-depressed HF patients, and 18 healthy controls, matched for demographic variables. Group differences were investigated with Statistical Parametric Mapping. RESULTS: Significant rCBF reductions in MDD-HF patients relative to both non-depressed HF patients and healthy controls were detected in the left anterior parahippocampal gyrus and hippocampus (ANOVA, p=0.008 corrected for multiple comparisons) and the right posterior hippocampus and parahippocampal gyrus (p=0.005 corrected). In the overall HF group, there was a negative correlation between the severity of depressive symptoms and rCBF in the right posterior hippocampal/parahippocampal region (p=0.045 corrected). CONCLUSIONS: These findings are consistent with the notion that the medial temporal region is vulnerable to brain perfusion deficits associated with HF, and provide evidence that such functional deficits may be specifically implicated in the pathophysiology of MDD associated with HF.     

Cognitive therapy for depressed adults with comorbid social phobia

BACKGROUND: Evidence suggests that comorbid depression influences the outcome of cognitive-behavioral treatment for patients presenting with social phobia. Little is known, however, about the influence of comorbid social phobia on the response to cognitive therapy (CT) for depression among adults presenting with recurrent major depressive disorder (MDD). These analyses seek to clarify this relationship. METHODS: Patients (N=156) with recurrent DSM-IV MDD entered CT (20% also met DSM-IV criteria for social phobia). Every week during the course of CT, clinicians assessed depressive symptoms and patients completed self-report instruments measuring severity of depression and anxiety. RESULTS: At presentation, outpatients with comorbid social phobia reported greater levels of depressive symptoms and clinicians rated their impairment as more severe, compared to their counterparts without social phobia. Patients with or without comorbid social phobia did not differ significantly in (1) attrition rates; (2) response or sustained remission rates; (3) time to response or sustained remission; or (4) rate of improvement in symptoms of depression or anxiety. LIMITATIONS: The lack of domain-specific measures limits inference with respect to the improvements in social anxiety that occur with CT of depression. CONCLUSIONS: These findings introduce the hypothesis that CT for depression may be flexible enough to treat the depressive symptoms of patients presenting with MDD who also suffer from social phobia.     

Diurnal rhythms in plasma cortisol, insulin, glucose, lactate and urea in pigs fed identical meals at 12-hourly intervals

Diurnal rhythms in plasma cortisol, insulin, glucose, lactate and urea concentrations were investigated in eight catheterized pigs of approximately 35 kg BW. Pigs were fed isoenergetic/isoproteinic diets at a restricted level (2.5 x maintenance requirement for energy) in two daily rations (06:00 and 18:00 hours) in order to obtain equal intervals between feed intake. Preprandial plasma cortisol concentration was 22+/-3 ng/mL in the morning and 14+/-2 ng/mL in the evening (p<0.025), whereas the concentrations of insulin, glucose, lactate, and urea were similar. In the postprandial period in the morning (06:00-09:00 hours) plasma cortisol, insulin and lactate concentrations (expressed as the total area under the curve) were greater (p<0.001) compared to the evening (18:00-21:00 hours) by 100%, 42%, and 24%, respectively, while postprandial plasma glucose and urea concentrations were not affected by time of the meal. When postprandial plasma concentrations were expressed as a response over preprandial concentrations (decremental or incremental area under the curve), the diurnal rhythm was not observed for cortisol and glucose, persisted for insulin and lactate, and appeared for urea with a smaller postprandial urea response (p<0.05) in the morning compared to the evening. We conclude that the diurnal rhythm in plasma cortisol is independent of feeding whereas the diurnal rhythms in plasma insulin, lactate and urea are unveiled by the morning/evening meals in pigs. At equal 12-h intervals between meals, the postprandial responses of lactate and urea show diurnal variations, each in a specific manner, which suggest decreased postprandial efficiency of carbohydrate metabolism and increased postprandial efficiency of protein metabolism in the morning compared to the evening.     

Age and gender differences in depressive symptomatology and comorbidity: an incident sample of psychiatrically admitted children

BACKGROUND: Studies indicate that major depressive disorder (MDD) is frequent in children but that it may be missed. This study determines the incidence of hospital-treated MDD based on the frequency of MDD in child psychiatric patients, and analyses effects of age and gender on depressive symptoms and psychiatric comorbidity. METHODS: One hundred ninety-nine consecutive child psychiatric patients were interviewed using a semi-structured diagnostic interview (K-SADS-PL). Comorbidity and symptoms were compared across age and gender. RESULTS: Current or partly remitted MDD was found in 42 children (21%). Thirty-eight (90%) had comorbid psychiatric disorder(s). Onset of the comorbid disorder was prior to onset of depression in 74% of cases. No significant gender-differences were found, but anhedonia, hypersomnia and decreased ability to concentrate were more frequent in the older age group. In contrast, feelings of worthlessness were more frequent in the younger age group. The number of melancholic symptoms was significantly associated with older age. CONCLUSION: MDD is frequent in child psychiatric patients aged 8-13 years. Age-but not gender-had significant effects on melancholy score and the prevalence of specific symptoms. Results suggest that MDD may be underdiagnosed in clinical samples unless careful examined with diagnostic interview.     

Sensitivity to reward and punishment and the prefrontal cortex in major depression

BACKGROUND: Patients with major depressive disorder (MDD) show neuropsychological impairments, including deficient executive functions and altered sensitivity to reward and punishment. METHODS: Executive functions (Wisconsin Card Sorting Test, WCST) and contingency learning based on the cumulative effect of reward and punishment (Iowa Gambling Test, IGT) were assessed in 30 medicated patients with unipolar MDD and in 20 healthy control volunteers. In the classic ABCD version of the IGT, advantageous decks are characterized by immediate small reward but even smaller future punishment. In the modified EFGH version, advantageous decks are characterized by immediate large punishment but even larger future reward. RESULTS: Patients with MDD were impaired in the WCST and in the ABCD version of the IGT but showed normal performances on the EFGH task. Depression, but not executive dysfunctions, significantly predicted performances on the EFGH task: less severe depressive symptoms were associated with better performances on the EFGH task. LIMITATIONS: The sample size was small and only few neuropsychological tests were used. Unmedicated patients were not assessed. Individual personality style, response strategies, and behavioral impulsivity were not investigated. CONCLUSIONS: Medicated patients with MDD show altered sensitivity to reward and punishment: immediate large reward enhanced related response patterns even when the strategy was disadvantageous and immediate large punishment did not prohibit related response patterns. Impairments in emotional decision-making were not a pure consequence of executive dysfunctions.     

Cognitive functioning in a population-based sample of young adults with a history of non-psychotic unipolar depressive disorders without psychiatric comorbidity

BACKGROUND: There is evidence for cognitive dysfunction in unipolar depression among middle-aged and elderly patients, but cognitive functioning among depressed young adults has scarcely been systematically investigated. The aims of the present study were to examine cognitive functioning among depressed young adults identified from the general population and to determine whether cognitive deficits vary as a function of different disorder characteristics, such as severity and age at onset. METHODS: Performance in verbal and visual short-term memory, verbal long-term memory and learning, attention, processing speed, and executive functioning was compared between a population-based sample of 21-35-year-olds with a lifetime history of non-psychotic unipolar depressive disorders without psychiatric comorbidity (n=68) and healthy controls derived from the same population (n=70). RESULTS: Depressed young adults were not found to be impaired in any of the assessed cognitive functions, except for some suggestion of mildly compromised verbal learning. Nevertheless, younger age at depression onset was associated with more impaired executive functioning. LIMITATIONS: The results may slightly underestimate of the true association between depression and cognitive impairments in the young adult population due to possible dropout of participants. Additionally, the problem of multiple testing was not entirely corrected. CONCLUSION: The findings from this study indicate that a lifetime history of non-psychotic unipolar depressive disorders among young adults without psychiatric comorbidity may be associated only with minimal cognitive deficits, even when some residual depressive symptoms are prevalent. However, early-onset depression may represent a more severe form of the disorder, associated with more cognitive dysfunction.     

A multi-channel near-infrared spectroscopy study of prefrontal cortex activation during working memory task in major depressive disorder

Many neuropsychological studies demonstrate impairment of working memory in patients with major depressive disorder (MDD). However, there are not enough functional neuroimaging studies of MDD patients seeking for the underlying brain activity relevant to working memory function. The objective of this study is to evaluate prefrontal hemodynamic response related to working memory function in patients with MDD. Twenty-four subjects with MDD and 26 age- and gender-matched healthy subjects were recruited for the present study. We measured hemoglobin concentration changes in the prefrontal and superior temporal cortical surface areas during the execution of working memory task (WM; 2-back, letter version) using 52-channel near-infrared spectroscopy (NIRS), which enables real-time monitoring of task-related changes in cerebral blood volumes in the cortical surface areas. MDD patients showed a smaller increase in lateral prefrontal and superior temporal cortex activation during the 2-back task and associated poorer task performance than healthy controls. The results coincided with previous findings in terms of working memory deficits and prefrontal cortex dysfunction in MDD patients, but contradicted with some previous fMRI studies that suggested increased cortical activity during the working memory task in patients with depression. The contradiction may, in part, be explained by a relatively low level of cognitive demand imposed on the subjects in the present study.     

Cognitive control adjustments and conflict adaptation in major depressive disorder

Individuals with major depressive disorder (MDD) show alterations in the cognitive control function of conflict processing. We examined the influence of these deficits on behavioral and event‐related potential (ERP) indices of conflict adaptation, a cognitive control process wherein previous‐trial congruency modulates current‐trial performance, in 55 individuals with MDD and 55 matched controls. ERPs were calculated while participants completed a modified flanker task. There were nonsignificant between‐groups differences in response time, error rate, and N2 indices of conflict adaptation. Higher depressive symptom scores were associated with smaller mean N2 conflict adaptation scores for individuals with MDD and when collapsed across groups. Results were consistent when comorbidity and medications were analyzed. These findings suggest N2 conflict adaptation is associated with depressive symptoms rather than clinical diagnosis alone.     

Impact of Early-Life Stress and Resilience on Patients with Major Depressive Disorder

Purpose

Early-life stress (ELS) has a long-lasting effect on affective function and may entail an increased risk for major depressive disorder (MDD). However, resilience can play a protective role against developing psychopathology. In this study, we investigated the relationships of depressive symptoms with ELS and resilience in MDD.

Materials and Methods

Twenty-six patients with MDD as well as age- and gender-matched healthy controls were included in this study. Each subject was assessed concerning ELS, resilience, and depressive symptom severity with self-report questionnaires. Independent samples t-test and Mann-Whitney test were performed to compare ELS and resilience between the patient and control groups. Spearman correlation analyses and linear regression analysis were conducted to investigate significant ELS and resilience factors associated with depressive symptoms.

Results

In the MDD patient group, subjects reported greater exposure to inter-parental violence, and five factor scores on the resilience scale were significantly lower in comparison to the control group. In linear regression analysis, in regards to resilience, depressive symptom score was significantly associated with self-confidence and self-control factors; however, ELS demonstrated no significant association with depressive symptoms.

Conclusion

Among resilience factors, self-confidence and self-control may ameliorate depressive symptoms in MDD. ELS, including inter-parental violence, physical abuse and emotional abuse, might be a risk factor for developing depression. Assessment of early-life stress and intervention programs for increasing resilience capacity would be helpful in treating MDD.     

Evidence for continuing neuropsychological impairments in depression

BACKGROUND: Neuropsychological deficits have been reported in patients with major depressive disorder (MDD) during an acute episode of MDD. Little is known whether these abnormalities persist when patients are remitted. The purpose of the present study was to describe the neuropsychological functioning of fully remitted, unmedicated patients with a history of MDD by focusing on tasks related to prefrontal cortex functioning. METHODS: Twenty-eight young to middle-aged, unmedicated, fully remitted patients with MDD were compared to 23 healthy control subjects on tasks from the Cambridge Automated Neuropsychological Test Battery (CANTAB) and the California Verbal Learning Test (CVLT). RESULTS: Patients with remitted MDD relative to controls were impaired on tasks of rapid visual information processing (RVIP), psychomotor performance and spatial working memory (SWM). After correction for residual depressive symptoms, deficits in sustained attention remained significant. LIMITATIONS: CANTAB tasks are not equated for difficulty, and difficulty differences between the CANTAB tasks and the CVLT are not known. CONCLUSIONS: These findings suggest deficits in sustained attention as vulnerability marker for MDD. The functional importance of this finding and the neuronal networks involved remain to be elucidated.     

Contextual recognition memory deficits in major depression are suppressed by cognitive support at encoding

Objectives

To investigate the effect of cognitive support (an associative orienting instruction at encoding) on contextual memory in depressed patients.

Methods

Seventeen patients (age 20-40 years, 14 women) diagnosed with major depressive disorder (MDD) and 22 healthy controls matched for age, gender and education completed a recognition memory task for item (object) and context (location), with or without an incidental binding cue at encoding. In addition, participants completed the vocabulary subtest of the Wechsler Adult Intelligence Scale (WAIS III) and the Wisconsin Card Sorting Test (WCST). Salivary samples were collected at 7 AM, 4 PM and 10 PM on the day of testing for cortisol and DHEA level measurement.

Results

Depressed patients showed a deficit in contextual memory in the absence of a binding cue but did not differ from healthy controls in item memory or when a binding cue was present. Cortisol and cortisol/DHEA ratios were lower in depressed patients compared to healthy controls and correlated with memory deficits.

Conclusions

Contextual memory deficits in MDD patients can be reduced by providing cognitive support at encoding.