A test of the interacting cognitive subsystems model using a laboratory analogue of depressive interlock

The interacting cognitive subsystems (ICS) model has been described as a useful framework within which to understand a wide variety of psychological phenomena. There is now a small literature of studies that have found support for many of the model's basic features. One feature that has not been studied is depressive interlock, described as uncontrollable, repetitious processing of negative themes. To further test some of the predictions derived from ICS, we compared a group of clinically depressed participants with a non‐depressed control group, using a specially designed cognitive task to examine the effects of emotional tone of stimuli on information processing. Results indicated that depression (but not euthymia) is characterized by perseverative responding for both positively and negatively emotionally toned self‐related material, but not for similar neutral material. This result is suggested as further empirical support for the ICS framework. Copyright © John Wiley & Sons, Ltd.     

Cognitive processes in depression

Tested hypotheses derived from Beck's cognitive theory of depression using 60 depressed and nondepressed males and females. Ss rated performance before and after they received feedback on a social interaction task. Ss then attempted to recall feedback and explain their post-feedback self-rating. Results showed that depressed males and females had more negative evaluation of present circumstances and poorer memory for feedback. Further, depressed males lowered their self-evaluation after feedback significantly more than did nondepressed males. Results with regard to differential response to neutral and positive feedback were not found because Ss apparently perceived all levels of feedback as somewhat negative. Data were partially supportive of Beck's cognitive theory of depression, especially with regard to males.     

Depression and self-esteem: An investigation that used behavioral and cognitive approaches to the treatment of clinically depressed clients

Investigated the relative effectiveness of the behavioral and cognitive approaches to the treatment of depression using clinically depressed clients and the relationship between self-esteem and depression before and after treatment. Sixteen depressed patients matched for sex, age, and levels of depression were involved, Ss were assigued to either the cognitive or the behavioral treatment groups. Three weeks¹ baseline followed by 8 weeks' treatment programme was given to Ss in each group. The results of the statistical analysis show that both treatment groups are effective in alleviating depression, but the cognitive treatment group improved at a faster rate than the behavioral group. No significant correlation between self-esteem and depression was observed at baseline. However, a significant inverse correlation was observed at posttreatment and follow-up. The findings showed that both behavioral and cognitive approaches were effective in the treatment of depression. However, the cognitive approach was slightly better than the behavioral approach.     

The replicable dimensions of the Beck Depression Inventory

Numerous studies have focused on the factor structure of the Beck Depression Inventory (BDI) because its underlying structure, once identified, may improve our conceptualizations of the cognitive processes in depression. These studies have produced a wide range of interpretations for the BDI, yet the replicability of these factor solutions across independent samples has not been demonstrated. In this study, a series of factor analyses were conducted that involved the use of a new factor matching procedure (FACTOREP), and both depressed patient and normal population samples. The results supported the presence of a large general factor only, which suggests that the items of the BDI are tapping a general construct of depressive symptoms rather than the variety of more specific constructs suggested by previous researchers.     

Impairments in cognitive control persist during remission from depression and are related to the number of past episodes: An event related potentials study

Recently, cognitive control deficits have been explored as a possible underlying trait abnormality in depression. In this study, cognitive control was investigated in homogeneous samples of never depressed controls, formerly depressed patients who had experienced a maximum of two depressive episodes and formerly depressed patients who had experienced at least three depressive episodes. We measured event related potentials (ERP) during a modified Stroop task in a sample of twenty-five formerly depressed patients and thirteen controls. Using this Stroop task, we manipulated subjects’ cognitive control for congruent and incongruent trials. These Stroop manipulations have generally been related to two post-stimulus ERP components related to cognitive control, the N2 and the N450.Behavioural measurements of reaction times and error rates did not indicate a difference in cognitive control between the samples. Left frontal N450 amplitude for the high conflict (HC) condition differentiated the three groups. While a N450 conflict-related modulation was significant in the healthy comparison group, such an effect was significantly reduced in the remitted depressed patients, particularly in the high recurrent group. Importantly, the amplitude of the N450 conflict-related enhancement was inversely correlated with the number of prior episodes. This pattern was not found for the N2 component.These findings suggest that deficits in cognitive control increase with each depressive episode and persist after symptom remission, suggesting that depressive episodes leave a “scar” on cognitive control processes.     

Brain event-related potentials to complex tones in depressed patients: Relations to perceptual asymmetry and clinical features

Brain event-related potentials (ERPs) to probe tones in a dichotic complex tone test were recorded from right-handed depressed patients (n= 44) and normal subjects (n= 19) at homologous sites over left and right hemispheres (F3, F4; C3, C4; P3, P4; O1, O2). There were no differences between groups in N1 or P2 amplitude, but patients had smaller P3 amplitude than did normal subjects. Depressed patients failed to show either the left ear advantage or behavior-related hemispheric asymmetry of P3 seen for normal subjects. Depressed patients also showed less differences in hemispheric asymmetry between same and different judgments. These findings indicate that the abnormal behavioral asymmetry for dichotic pitch discrimination in depressed patients reflects a reduction in hemispheric asymmetry and is related to relatively late stages of cognitive processing.     

Neuropsychological deficits among patients with late-onset minor and major depression.

Cognitive ability of minor depressed patients (N=28), major depressed patients (N=26) and healthy elderly (N=38) was examined cross-sectionally to determine if cognitive abilities of patients with late-onset depression decrease with increasing severity of disease and if cognitive scores for minor depressed patients fall between those of healthy elderly and major depressed patients. A pooled within-group principal component analysis of cognitive test scores identified five components, three of which showed significant group differences. Verbal Recall and Maintenance of Set separated controls from major depressed patients and minor from major depressed patients. Executive Functioning separated controls from minor depressed patients, and Working Memory was borderline for separating controls from major depressed patients. The component representing Nonverbal Recognition was not statistically significant. Partial correlations controlling for age and education indicate that cognitive performance does decrease as severity of depression increases, and the magnitude of the change varies from a trend to a significant deficit depending on the cognitive domain. This decline in cognitive performance parallels a similar trend observed in neuroanatomical studies in which the volume of the frontal and temporal lobes decrease with increasing severity of depression.     

Mapping for dyslexia and related cognitive trait loci provides strong evidence for further risk genes on chromosome 6p21

In a genome‐wide linkage scan, we aimed at mapping risk loci for dyslexia in the German population. Our sample comprised 1,030 individuals from 246 dyslexia families which were recruited through a single‐proband sib pair study design and a detailed assessment of dyslexia and related cognitive traits. We found evidence for a major dyslexia locus on chromosome 6p21. The cognitive trait rapid naming (objects/colors) produced a genome‐wide significant LOD score of 5.87 (P = 1.00 × 10^?7) and the implicated 6p‐risk region spans around 10 Mb. Although our finding maps close to DYX2, where the dyslexia candidate genes DCDC2 and KIAA0319 have already been identified, our data point to the presence of an additional risk gene in this region and are highlighting the impact of 6p21 in dyslexia and related cognitive traits. © 2010 Wiley‐Liss, Inc.     

Cognitive development among children with early‐treated phenylketonuria

Previous research supports the notion that children with early‐treated classical phenylketonuria (PKU) have specific cognitive deficits in executive function skills. These deficits may relate to depressed levels of dopamine, due to defective tyrosine synthesis. We investigated whether deficits reported for preschoolers with early‐treated PKU are manifested also among school‐age children with PKU, and whether cognitive performance among the latter group is related to phenylalanine level at time of testing. Seventeen children with PKU and 17 age‐, sex‐, and IQ‐matched controls were tested individually on measures of executive functions. The results demonstrate that executive function deficits reported for preschoolers with PKU were not manifested in the school‐age PKU children included in this study. The authors discuss the implications of these findings for theories of the development of executive function skills.     

Extreme nonresponse in cognitive therapy: can behavioral activation succeed where cognitive therapy fails?

In a recent placebo-controlled comparison, behavioral activation was superior to cognitive therapy in the treatment of moderate to severely depressed adults. Moreover, a subset of patients exhibited a pattern of extreme nonresponse to cognitive therapy on self-reports of depression not evident on the clinician ratings. These patients were severely depressed, functionally impaired, and had primary support group problems; most also described themselves as having life-long depressions. Comparable numbers of patients with such characteristics were assigned to behavioral activation, indicating that randomization did not fail, and most instances occurred in the context of adequate cognitive therapy. If this pattern of self-reported extreme nonresponse to cognitive therapy replicates, it would suggest that there might be a subset of patients who see themselves as doing better with sustained attention to behavior change in time-limited treatment.     

Genome‐wide association study of cognitive flexibility assessed by the Wisconsin Card Sorting Test

Cognitive flexibility is a critical component of executive function and is strongly influenced by genetic factors. We conducted a genome‐wide association study of cognitive flexibility (as measured by perseverative errors on the Wisconsin Card Sorting Test) in two sets of African American (AA) and European American (EA) subjects (Yale‐Penn‐1: 1,411 AAs/949 EAs; Yale‐Penn‐2: 1,178 AAs/1,335 EAs). We examined the association of cognitive flexibility with genotyped or imputed SNPs across the genome. In AAs, two correlated common single nucleotide polymorphisms (SNPs) (rs7165213/rs35633795) in the downstream region of the noncoding gene LOC101927286 on chromosome 15 showed genome‐wide significant (GWS) associations with cognitive flexibility (Yale‐Penn‐1: p = 6.0 × 10^?9/1.3 × 10^?8; Yale‐Penn‐2: p = .029/.010; meta‐analysis: p = 4.2 × 10^?7/1.0 × 10^?7) in the same effect direction. In EAs, no GWS associations were observed. Enriched gene sets identified by Data‐driven Expression‐Prioritized Integration for Complex Traits (DEPICT) analysis of the top SNPs (p_{meta‐analysis} < 10^?5) included the signalosome and ubiquitin‐specific peptidase 9, X‐linked (USP9X) subnetwork in AAs, and abnormal frontal and occipital bone morphology in EAs. We also performed polygenic risk score (PRS) analysis to examine the genetic correlation of cognition‐proxy phenotypes (general cognitive function, education attainment, childhood intelligence, and infant head circumference) and cognitive flexibility in EAs. The PRS derived from general cognitive function‐associated SNPs was significantly associated with cognitive flexibility. Nongenetic factors (age, education, sex, and tobacco recency) also exerted significant effects on cognitive flexibility. Our study demonstrates that both genetic and nongenetic factors impact cognitive flexibility, and variants in genes involved in protein degradation and brain development may contribute to population variation in cognitive function.     

Self-schema in irritable bowel syndrome and depression

Some investigators have suggested that irritable bowel syndrome (IBS) represents a physiologic expression of an affective disorder. This study investigated whether IBS patients differed in their self-schema from depressed patients. Self-schema refers to a cognitive framework of the individual's beliefs, attitudes, and self-perceptions which is stored in memory and which influences incoming information. The sample consisted of 21 IBS patients, 21 psychiatric outpatients with major depression (MD), and 19 normal controls. All groups were age matched. Subjects completed a structured psychiatric interview (Diagnostic Interview Schedule (DIS) and a Beck Depression Inventory (BDI), in addition to a test of self-schema, which involved rating and recall of a variety of "depressed" and "nondepressed" content adjectives. Consistent with previous work on self-schema, the MD group recalled significantly more depressed adjectives rated under the self-referent task than the Control group (p less than 0.05) and, also, the IBS group (p less than 0.05). Most striking was the finding that a subgroup of IBS patients who met criteria for MD (43% of the sample) recalled significantly more self-referent nondepressed words (and less self-referent depressed words) than the MD group (p less than 0.05). In other words, IBS patients with MD do not view themselves as depressed. These findings suggest that while some IBS and depressed psychiatric outpatients may share depressive symptoms, these groups can be differentiated by their self-schema.     

Suppressible alleles in a wide domain regulatory gene in Aspergillus nidulans

Summary The areA gene of Aspergillus nidulans is a one of the better studied eukaryotic wide domain regulatory genes, necessary for the expression of most structural genes involved in the utilization of a wide variety of nitrogen sources (Arst and Cove 1973; Arst 1983). Here we report the isolation and properties of areA alleles suppressible by translational suppressors (Roberts et al. 1979). Thus we show formally that the areA gene specifies a protein rather than an RNA product and we show that it is possible to generate by external suppression areA gene products with modified properties.     

Deficient inhibition of emotional information in depression

BACKGROUND: There are numerous indications that impaired inhibition of negative affective material could be an important cognitive component of depression. To study whether impaired inhibition of negative affect is a cognitive vulnerability factor explaining (recurrent) depression, inhibition of positive and negative affective stimuli was examined in hospitalized depressed patients, formerly depressed individuals and never-depressed controls. METHODS: To investigate inhibitory dysfunctions in the processing of emotional material, we used an affective modification of the negative priming task with pictures of sad and happy facial expressions. RESULTS: Compared to never-depressed controls, depressed patients showed a specific failure to inhibit negative information, whereas inhibition function for positive material was unaffected. Surprisingly, formerly depressed individuals demonstrated impaired inhibition of negative and positive information. LIMITATIONS: Because of the significant correlations between depression and anxiety self-report scores, the observed reduced inhibitory effect toward negative material in the depression group cannot strictly be attributed as depression-specific. CONCLUSIONS: In accordance with our hypothesis, strongly impaired inhibition of negative affect was found in depressed patients. Based on the present findings, we argue that impaired inhibition of negative affect could be an important construct in cognitive theories on depression linking cognitive biases to neuropsychological impairments in depression. The data in the formerly depressed individuals are less conclusive and several hypotheses are detailed that could explain how the absence of inhibition of affective information could relate to recurrent depression.     

Individualized versus standardized therapy: A comparative evaluation with obsessive-compulsive patients

The aim of this study was to investigate whether individualized tailor-made behavioural treatment based upon a problem analysis of each case was more effective than a standardized behavioural treatment protocol. Twenty-two obsessive-compulsive patients were randomly assigned to two treatment conditions: (1) tailor-made cognitive behavioural therapy and (2) standardized exposure in vivo therapy. Treatment in both conditions led to significant improvements on obsessive-compulsive targets and on the Maudsley Obsessional-Compulsive Inventory. Improvement generalized to general levels of psychopathology, depressed mood and social anxiety. Contrary to expectations the individualized treatment was not more effective than the standardized exposure therapy.     

Is postnatal depression a distinct subtype of major depressive disorder? An exploratory study

Postnatal depression (PND) has an estimated prevalence of 6.5 to 12.9%. In addition to the direct consequences for women, PND also interferes with the maternal-infant interaction, contributing to long-term cognitive and emotional impairments in exposed offspring. It is unclear how PND differs from major depressive disorder (MDD) more generally, and if PND represents a distinct subtype of depression. We explored whether women with a history of PND have specific differences in brain activation associated with sex hormone changes during the late luteal phase of the menstrual cycle, compared to parous women with either a past history of MDD outside of the postnatal period, or an absent history of MDD (‘never depressed’). Thirty mothers (history of PND (n = 10), history of MDD (n = 10), and ‘never depressed’ (n = 10)) underwent blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) acquisition during an emotional faces task. Amygdala activity was analysed using a region of interest (small volume correction) approach. There was a significant reduction in BOLD response to positive emotional faces in the right amygdala in women with a history of PND compared to women with a history of MDD. A similar but non-significant trend was found in the left amygdala in women with a history of PND compared to ‘never depressed’ women. Our findings support the hypothesis that women with vulnerability to PND represent a distinct subgroup of women with a differential sensitivity to changes in sex hormones. Further, albeit highly tentative, they provide a putative biomarker that could assist in detection of women at-risk to PND.

     

Cognitive function in adults with type 2 diabetes and major depression

The aim of this study was to identify characteristics of neuropsychological functioning among type 2 diabetic adults with and without major depression. Twenty type 2 diabetics with major depression, 20 non-depressed type 2 diabetics and 34 controls without diabetes or depression were compared. A mixed effects repeated measures analysis of covariance indicated significant differences in overall cognitive functioning between diagnostic groups, specifically depressed diabetics demonstrated greater cognitive dysfunction than controls. Further comparisons indicated that depressed diabetics performed significantly worse than non-depressed diabetics in attention/information processing speed. Relative to controls, depressed diabetics performed significantly worse in attention/information processing speed and executive functioning, while there was a trend for non-depressed diabetics to perform worse in executive functioning. These findings suggest that depression negatively impacts cognitive performance among adults with type 2 diabetes, which may have implications for neural circuitry underlying cognitive and mood changes in diabetic patients.     

Memory after menopause: preliminary considerations of hormone influence on cognitive functioning

Summary Oestrogen has been shown to have a wide variety of organisational and activating effects on brain structure and function. Despite the significant amount of research investigating the relation and effects of oestrogen to cognitive performance in menopausal women over the past two decades, studies have failed to produce consistent findings. This paper reports on evaluations of eighty-one community-based postmenopausal Australian women comparing current, past and never users of hormone therapy (HT) on a wide range of cognitive measures of general, verbal and visual memory, delayed recall, attention, concentration and verbal comprehension. Few significant differences were found among the three groups in the demographic profile, health status or psychological functioning. Although never users had significantly lower scores on verbal memory than past users, the differences were not statistically significant when adjustments were made controlling for age, education level, verbal comprehension, attention and concentration. These findings challenge long-held beliefs regarding the usefulness of oestrogen supplements as a protective factor against cognitive decline in older women’s later years.