Michael Gemar

Mood-induced changes on the Implicit Association Test in recovered depressed patients.

A mood induction paradigm was used to examine dysphoria-related changes in two types of cognitive processing in individuals who had previously experienced depression. Formerly depressed patients (n = 23) and never-depressed controls (n = 27) completed the Dysfunctional Attitudes Scale, a self-report measure of effortful processing, and performed the Implicit Association Test, an automatic-reaction time task that measures evaluative bias, before and after a negative-mood induction. The formerly depressed group showed both an increase in endorsement of dysfunctional attitudes and a more negative evaluative bias for self-relevant information after the induction, relative to controls--however, there was no association between the mood-linked changes observed on these two measures. The shift in evaluative bias shown by the formerly depressed group was similar to that seen in a group of 32 currently depressed individuals. These findings suggest that even a mild negative mood in formerly depressed individuals can reinstate some of the cognitive features observed in depression itself.

A cognitive science perspective on kindling and episode sensitization in recurrent affective disorder

A cognitive science analysis of the interaction between psychological stress and the neurobiology of affective illness highlights a number of mechanisms relevant to the study of recurrence in major depressive disorder. It builds on observations previously offered by Post (1992) regarding the importance of kindling and sensitization effects in determining activation of neural structures, and proposes a model of knowledge structure activation that follows similar parameters. Vulnerability to depressive relapse/recurrence is determined by the increased risk of particular negative patterns of information processing being activated in depressed states. As is found in studies of kindling and behavioural sensitization, the likelihood of cognitive patterns being activated is dependent on the frequency of past usage, and increased reliance on these patterns of processing makes it easier for their future activation to be achieved on the basis of increasingly minimal cues. This model suggests that the processes related to relapse/recurrence and episode onset may not be isomorphic and, as such, treatments that emphasize relapse prevention strategies should take this distinction into account.

A naturalistic visual scanning approach to assess selective attention in major depressive disorder

Cognitive biases in information processing play an important role in the etiology and maintenance of emotional disorders. A new methodology to measure attentional biases is presented; this approach encourages subjects to scan and re-scan images with different thematic content, while the pattern of their attentional deployment is continuously monitored by an eye-tracking system. Measures of attentional bias are the total fixation time and the average glance duration on images belonging to a particular theme. Results showed that subjects with depressive disorder (n=8; Beck Depression Inventory Score>/=16) spent significantly more time looking at images with dysphoric themes than subjects in the control group (n=9). Correlation analysis revealed that the differences between the fixation times of the two groups are significantly correlated with the valence ratings, but not with the arousal ratings of the images. The average glance duration on images with social, neutral and threatening themes were similar for both groups, while the average glance duration on images with dysphoric themes was significantly larger for subjects with depressive disorder. The above results suggest that subjects with depressive disorder selectively attend to mood-congruent material and that depression appears to influence the elaborative stages of processing when dysphoric images are viewed.

A priming methodology for studying self-representation in major depressive disorder

The authors investigated processing of self-descriptive emotional information in depression using a modified Stroop color-naming task. Depressed (n = 58) and nondepressed control (n = 44) participants were required to name the color in which positive and negative adjectives, differing in the degree to which they described the person, were presented. These target adjectives were primed by emotional phrases that also varied according to degree of self-reference. Analyses indicated that depressed participants showed slower color-naming latencies for self-descriptive negative targets primed by self-descriptive negative phrases than for any other prime-target condition. No effect of prime-target relation was found for positive material with depressed participants, and nondepressed controls showed no effect of prime-target relation for material in either valence. These results support the hypothesis that negative information about the self is highly interconnected in the cognitive system of depressed patients.

Cognitive therapy for bipolar depression : A pilot study

Objective: While the efficacy of cognitive-behaviour therapy (CBT) for the treatment of acute unipolar major depression is well-documented, there is almost no data evaluating its utility in the treatment of bipolar depression. This pilot study compares the efficacy of CBT combined with mood-stabilizer pharmacotherapy for bipolar depression and CBT alone for unipolar depression. Method: A matched-case control design was used to evaluate outcomes following 20 sessions of CBT in 11 depressed bipolar patients and 11 matched recurrent unipolar depressed control subjects. Results: Bipolar depressed patients achieved similar levels of reduction in depressive symptoms following CBT, as did the unipolar depressed group. However, on measures of more pervasive dysfunctional attitudes, bipolar patients did not improve to the same degree. Conclusions: Preliminary findings suggest that CBT warrants further investigation as an effective psychosocial intervention for depression in bipolar patients already receiving ongoing mood-stabilizing pharmacotherapy.

Changes in Autobiographical Memory Specificity following Cognitive Behavior Therapy and Pharmacotherapy for Major Depression

Background: An important cognitive marker of clinical depression is a reduced ability to be specific in recalling personal memories, a phenomenon coined ‘overgeneral memory’. Overgeneral memory is considered as a stable cognitive trait that is intrinsically linked with depression and independent of mood state. Previous studies show that autobiographical memory is modifiable. Sampling and Methods: This study investigated whether autobiographical memory is differentially affected by treatment type. Depressed patients were randomly assigned to receive either cognitive behavior therapy (CBT) for depression or pharmacotherapy (PHT). Results: The proportion of categoric memories decreased and the proportion of specific memories increased following both types of treatments, adding support to the view that overgeneral memory is modifiable. CBT also had a greater impact on reducing extended overgeneral memories compared to PHT. Conclusions: The results from the current study are important in that they show that overgeneral memory can be targeted and modified through brief treatment. The clinical significance of the finding that there was a greater decrease in extended memories in the CBT group is unclear.