Depressive deficits and bias: a direct comparison of two implicit measures of memory

Repeated findings of depressive deficits and mood‐congruent biases on explicit measures of memory have lent much support to cognitive models of depression. However, studies to date have been inconclusive with respect to such deficits or biases on implicit measures. Given current assertions that implicit use of memory is far more pervasive than explicit use, clarification of these issues has important implications for our understanding of cognitive factors in clinical depression and its treatment. We consider both these issues, and, in particular, we follow up the suggestion by Roediger and McDermott (1992) that conceptually driven implicit measures of memory are more appropriate to detect depressive bias than those that are typically used, which are perceptually driven. In this study we directly compare the memory performance of 24 clinically depressed patients with 24 nondepressed controls on a perceptually driven implicit task (fragment completion) and a comparable task that is more conceptually driven (cued fragment completion). Although depressive deficits were obtained on both these measures, no bias was revealed. We consider alternative research designs for clarification of these findings. Copyright © 2001 John Wiley & Sons, Ltd.     

Implicit and explicit memory biases in mixed anxiety-depression

BACKGROUND: This study investigated and compared implicit and explicit memory biases in anxiety, depression and mixed anxiety-depression. METHOD: Outpatients who were either depressed only (n=18), anxious only (n=18) or mixed (anxious and depressed) (n=18) were compared to normal controls (n=18) on self-report measures and typical experimental tasks assessing memory biases. The implicit memory test was a word identification task and the explicit memory test was an incidental free recall with depression relevant, anxiety relevant, emotional positive and neutral words. RESULTS: The depressed group showed a positive implicit memory bias and a mood-congruent bias at free recall. The anxious group presented an overall higher priming effect in the implicit memory test, whilst the mixed group exhibited no difference in the quantity of priming effect compared to normal controls and recalled more anxious relevant words than other word types. LIMITATIONS: Because of the dimensional perspective adopted in the present study, the mixed group was composed of both DSM-IV sub-threshold (n=5) and supra-threshold (n=13) patients. CONCLUSIONS: These results show a specific pattern for the mixed group and suggest that mixed anxiety-depression represents a distinct clinical group.     

Mood-congruent effect in self-relevant information processing: a study using an autobiographical memory recall task

The pattern of the mood-congruent effect in an autobiographical memory recall task was investigated. Each subject was randomly assigned to one of three experimental conditions: positive mood, negative mood (induced with music), and control groups (no specific mood). Subjects were then presented with a word at a time from a list of trait words, which were pleasant or unpleasant. They decided whether they could recall any of their autobiographical memories related to the word, and responded with "yes" or "no" buttons as rapidly and accurately as possible. After the task, they were given five minutes for an incidental free recall test. Results indicated that the mood-congruent effect was found regardless of whether there was an autobiographical memory related to the word or not in both positive and negative mood states. The effect of moods on self-relevant information processing was discussed.     

Autobiographical memories in major depressive disorder

The objective of this research was to study the relation between the processing and recall of information in major depressive disorder. An autobiographical memory task was applied to 42 subjects with a diagnosis of major depressive disorder, 28 subjects with a diagnosis of panic disorder and 51 subjects without any psychological disorder. We used clinical scales for the evaluation of depression and anxiety. The results of the three groups, and both assessment periods of depressed subjects, were compared. The results indicate the existence, in severely depressed subjects, of a bias in processing and recalling negative information. We associate this situation to the existence of negative contents in self-schemas and processing and recall of information consistent with these schema contents. Based on the obtained results, we consider that the onset and maintenance of depression is more related to the information encoding and recall processes, controlled by the self's negative schemas, than with negative thoughts.     

Depressed mood in multiple sclerosis: relationship to capacity-demanding memory and attentional functioning.

Because it is theorized that depression results in reduced available attentional capacity that, in turn, can explain the impaired performance on capacity-demanding tasks in depressed individuals, the authors predicted that multiple sclerosis (MS) patients with depressed mood would have difficulty with these types of tasks. Twenty depressed mood MS participants were compared with 41 nondepressed mood MS participants and 8 nondepressed mood controls on 5 attentional capacity-demanding clinical memory and attentional tasks and 3 tasks with minimal capacity demands. Depressed mood MS patients performed significantly worse than both nondepressed mood groups on the 3 speeded capacity-demanding attentional measures but not on any of the tasks requiring few capacity demands, supporting the authors' predictions. The possibility that the impaired performance of depressed mood MS patients on speeded attentional tasks was mediated by reduced verbal working memory capacity, impaired deployment of executive strategies that access working memory capacity, or psychomotor slowing is explored.     

Metacognition and depressive realism: evidence for the level-of-depression account

Introduction. The present study examined the relationship between metacognition (i.e., "thinking about thinking") and depression. More specifically, the depressive realism hypothesis (Alloy & Abramson, 1979), which posits that depressed people have a more accurate view of reality than nondepressed people, was tested. Methods. Nondepressed, mildly depressed, and moderately depressed individuals predicted their memory performance by making judgements of learning after each studied item. These predictions were then compared with actual performance on a free recall task to assess calibration, an index of metacognitive accuracy. Results and conclusions. Consistent with the depressive realism hypothesis, mild depression was associated with better calibration than nondepression. However, this "sadder but wiser" phenomenon appears to only exist to point, as moderate depression and nondepression showed no calibration differences. Thus, the level-of-depression account of depressive realism is supported.     

Metacognition and depressive realism: Evidence for the level-of-depression account

Introduction. The present study examined the relationship between metacognition (i.e., “thinking about thinking”) and depression. More specifically, the depressive realism hypothesis (Alloy & Abramson, 1979), which posits that depressed people have a more accurate view of reality than nondepressed people, was tested.

Methods. Nondepressed, mildly depressed, and moderately depressed individuals predicted their memory performance by making judgements of learning after each studied item. These predictions were then compared with actual performance on a free recall task to assess calibration, an index of metacognitive accuracy.

Results and conclusions. Consistent with the depressive realism hypothesis, mild depression was associated with better calibration than nondepression. However, this “sadder but wiser” phenomenon appears to only exist to point, as moderate depression and nondepression showed no calibration differences. Thus, the level-of-depression account of depressive realism is supported.     

The relationship between mood instability and depression: Implications for studying and treating depression

Background

Most individuals with depressed mood report mood fluctuations (Mood Instability) within hours or days. This is not recognized in diagnostic criteria or standard rating scales for depression.

Hypothesis

That mood instability is a distinct component of the development of depression that has been omitted from criteria for depression because of reliance on retrospective recall and structured interviews. The inclusion of Mood Instability would enhance research into causes and treatment of depression.

Studies

We examined three datasets that used retrospective and prospective measures of depressed symptom ratings and mood instability to determine the relationship between the two. Study 1 used data from the 1991 UK Health and Lifestyle Surveys (HALS). Studies 2 and 3 used clinical samples. The scales used to assess mood instability were the mood instability factor from the Eysenck Personality Inventory Neuroticism Scale, the Affective Lability Scale (ALS), and the Visual Analogue Depression Scale (VAS). The depression scales (depressive symptoms) were the General Health Questionnaire (GHQ) depression factor, the Beck Depression Inventory IA (BDI) and the mean from the Visual Analogue Depression Scale (VAS). We used partial correlation analysis to assess the association between mood instability and depression and exploratory factor analysis to determine the factor structure of items pooled from the mood instability and depression scales from studies 1 and 2.

Results

Mood Instability was found to be moderately associated with depressive symptoms. The Pearson’s r-values ranged from 0.49 to 0.57. The correlation was lower when recalling mood in the past. The factor analytic solution supported the hypothesis that MI and depressive symptoms are related but distinct constructs.

Conclusions

Reliance exclusively on the retrospective assessment of depressive symptoms has occluded the widespread occurrence of mood instability. Including Mood Instability in diagnostic and assessment criteria would enhance causal and treatment research in depression.     

Autobiographical memory impairment in obstructive sleep apnea patients with and without depressive symptoms

Obstructive sleep apnea is associated with memory impairments, and higher rates of depressive symptoms and major depressive disorder compared with community estimates. Autobiographical memory overgenerality, a behaviour characterized by difficulty recalling specific memories from one's own life, is recognized as a marker of depression. Previous studies have demonstrated the predictive quality of specific autobiographical memory recall on the course of depression in patients with obstructive sleep apnea. However, it remains unclear whether impaired autobiographical memory is simply a feature of depression, or whether it is also impaired in patients with obstructive sleep apnea without depression. This study aimed to investigate whether autobiographical memory impairments can be observed in patients with obstructive sleep apnea, independent of the severity of depressive symptoms. Twenty‐one patients with obstructive sleep apnea symptomatic for depressive symptoms (mean age = 43.43 years, SD = 9.97), 17 patients with obstructive sleep apnea asymptomatic for depressive symptoms (mean age = 40.65 years, SD = 9.39), and 20 healthy controls without sleep‐disordered breathing (mean age = 32.80 years, SD = 6.69) completed an Autobiographical Memory Test. Patients with obstructive sleep apnea symptomatic for depressive symptoms recalled significantly fewer specific memories when compared with healthy controls (P = 0.010). No difference in the recall of specific autobiographical memory was observed between symptomatic and asymptomatic patients with obstructive sleep apnea. With regard to valence, symptomatic patients with obstructive sleep apnea recalled significantly fewer negative specific memories when compared with controls (P = 0.010). Impairment in specific autobiographical memory recall can be observed in patients with obstructive sleep apnea, regardless of the severity of depressive symptoms; however, this effect may not be as prominent in younger patients with obstructive sleep apnea.     

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.     

Depression in multiple sclerosis: relationship to working memory capacity.

Recent research has shown that depression in multiple sclerosis (MS) is associated with deficits on cognitively demanding tasks. One explanation for this relationship is that depressed MS patients may have reduced working memory capacity. The present study was designed to test this hypothesis. Depressed MS patients were compared with nondepressed MS patients and nondepressed healthy controls on a task of working memory capacity (reading span) and a short-term memory task not taxing working memory capacity (word span). In support of the capacity-reduction model, compared with the nondepressed groups, depressed MS patients performed significantly worse on reading span (p<.001) but not on word span. Additionally, reading span was significantly correlated with capacity-demanding tasks shown to be impaired in depressed MS patients in previous reports. Results suggest that depressed MS patients are characterized by limited working memory capacity and that the central executive component of the working memory system may be most affected.     

Rumination and cigarette smoking: a bad combination for depressive outcomes?

Ruminative coping has been shown to heighten the risk and severity of depression. The authors hypothesized that ruminators who smoke would experience greater depressive symptoms than ruminators who do not. The rationale is that, by heightening attentional focus, nicotine may increase ruminators' ability to focus on negative thoughts, augmenting depressed mood. Participants (N = 145) self-reported smoking status, rumination, and current and lifetime depressive symptoms, including depressed mood. Results showed that rumination accounted for a larger amount of variance in current and past depressed mood and severity of lifetime depressive symptoms among smokers than nonsmokers. Noncorrelational, experimental research should directly test whether nicotine worsens depressed mood among ruminative smokers. Such evidence would be surprising because it would contradict the assumption that nicotine dispels negative moods.     

Depressed adolescents of depressed and nondepressed mothers: tests of an interpersonal impairment hypothesis

Two groups of depressed youngsters were compared. From an interpersonal perspective, it was hypothesized that depressed adolescents of depressed mothers would have significantly more interpersonal dysfunction than depressed youngsters of nondepressed mothers. In a large community sample of youth and their families, 65 depressed offspring of women with histories of a major depressive episode or dysthymia were compared with 45 depressed offspring of never-depressed women. As predicted, after controlling for current symptoms and family social status variables, depressed offspring of depressed mothers displayed significantly more negative interpersonal behaviors and cognitions compared with depressed offspring of nondepressed mothers, but they did not differ on academic performance. Implications concerning mechanisms, course, and consequences of different forms of adolescent depression are presented.     

Prefrontal cortex activity differentiates processes affecting memory in depression

Deficits in the initiation and utilization of strategies contribute importantly to memory impairments in depression. Other research on depression has documented memory biases toward negative and away from positive material. This study investigated brain mechanisms accompanying the initiative deficit and negative bias processes affecting memory in depressed individuals. Electroencephalography was recorded prior to and during emotional narratives and correlated with subsequent memory recognition of narrative material. Hypothesized to reflect strategy initiation, bilateral activity of the prefrontal cortex (PFC) preceding a sad narrative was associated with memory performance for that narrative in nondepressed controls only. Negative memory bias in depressed participants was inferred from their association between right prefrontal activity during the sad narrative and memory performance, consistent with research implicating that region in withdrawal-related unpleasant emotions. These results highlight the importance of distinguishing processes that influence memory performance when investigating the neural mechanisms of cognitive deficit and bias in depression.     

Depression vulnerabilities in patients with different levels of depressive symptoms after acute coronary syndromes

BACKGROUND: Cognitive, behavioral, and interpersonal vulnerabilities have been studied in patients fulfilling diagnostic criteria for major depression and dysthymia. The extent to which these vulnerabilities are present in cardiac patients with mild to moderate depressive symptoms--a risk factor for mortality--is unknown. Moreover, few studies have examined interrelations among depression vulnerabilities. METHODS: A consecutive cohort of 314 patients with acute coronary syndrome completed the Beck Depression Inventory (BDI) and measures of cognitive, behavioral, and interpersonal vulnerabilities (Dysfunctional Attitudes Scale, Pleasant Events Schedule for the Elderly, Dyadic Adjustment Scale, and an inventory of role transitions) within 1 week of hospital admission. Of the patients, 166 were classified as nondepressed (BDI score, 0-4), 91 as mildly depressed (BDI score, 10-16), and 57 as moderately to severely depressed (BDI score, >16). RESULTS: Compared with nondepressed patients, both mildly depressed and moderately to severely depressed patients exhibited higher mean levels of all vulnerabilities as well as a higher prevalence of more than one elevated vulnerability, defined by threshold scores. Vulnerabilities were only minimally interrelated (r = 0.01-0.25), and they were independently associated with mild and moderate depressive symptom status. CONCLUSIONS: This is the first study to show that cognitive, behavioral, and interpersonal depression vulnerabilities are uniquelyassociated with concurrent depressive symptoms. There appeared to be only modest overlap between vulnerabilities, supporting the idea that depression in medically ill patients is a multifaceted phenomenon, even in the presence of minimally elevated depressive symptoms. Longitudinal studies are required before causality and treatment implications can be addressed.     

The dexamethasone suppression test in delusional depression. Further findings

The results of the overnight 1 mg dexamethasone suppression test (DST) administered to 26 unipolar delusional depressed patients and 47 unipolar non-delusional depressed controls are reported. There were no significant differences between the rates of abnormal responses in the two groups. However, there was a higher percentage of normal responses in the delusional depressive sample with mood incongruency. While 55% of the mood-congruent depressive patients were non-suppressors, only 12% of the depressed patients with mood-incongruent psychotic features had abnormal DST responses.     

Emotional bias and inhibitory control processes in mania and depression

BACKGROUND: Despite markedly different clinical presentations, few studies have reported differences in neuropsychological functioning between mania and depression. The disinhibited behaviour characteristic of mania and evidence that subgenual prefrontal cortex is differentially activated in mania and depression both suggest that dissociable deficits will emerge on tasks that require inhibitory control and are subserved by ventromedial prefrontal cortex. METHODS: Manic patients and controls undertook computerized neuropsychological tests of memory and planning ability. In addition, manic and depressed patients were directly compared with controls on a novel affective shifting task that requires inhibitory control over different components of cognitive and emotional processing. RESULTS: Manic patients were impaired on tests of memory and planning. Importantly, affective shifting performance of manic patients differed from that of depressed patients. Manic patients were impaired in their ability to inhibit behavioural responses and focus attention, but depressed patients were impaired in their ability to shift the focus of attention. Depressed patients exhibited an affective bias for negative stimuli, and we believe this to be the first demonstration of an affective bias for positive stimuli in manic patients. CONCLUSIONS: Observed impairments on tests of memory and planning suggest a global pathology for mania consistent with previous profiles for this disorder and similar to established profiles for depression. The results on the affective shifting task demonstrate the presence of mood-congruent bias and dissociable components of inhibitory control in mania and depression. Against a background of memory and planning impairments in the two groups, these findings are consistent with a role for the ventromedial prefrontal cortex in mediating mood-cognition relationships.     

Psychotic features in major depression: Is mood congruence important?

We studied outcome and family history in 203 patients with psychotic depression. Patients whose psychotic features were mood-incongruent were significantly younger and had a slightly poorer outcome. Morbid risks for affective disorder and schizophrenia among relatives distinguished these mood-incongruent patients from patients with non-psychotic depression but not from patients with schizophrenia. In contrast, depressive probands with mood-congruent psychotic features resembled probands with non-psychotic depression and differed significantly from schizophrenia probands in terms of family history. While depressed patients with mood-congruent psychotic features experienced poorer short-term outcome relative to non-psychotic depressed patients, a 40-year follow-up has shown that these differences disappear over time. Moreover, these two groups are quite similar according to family history data. Both family history and short-term outcome data suggest that major depression with mood-incongruent psychotic features cannot be classified altogether with either affective disorders or schizophrenia. More definite conclusions must await the results of long-term outcome and family studies of these patients presently underway.     

Mood-congruent memory in daily life: Evidence from interactive ambulatory monitoring

Evidence from the psychological laboratory indicates that emotional states tend to facilitate the encoding and retrieval of stimuli of the same emotional valence. To explore mood-congruent memory and the role of arousal in daily life, we applied a new interactive ambulatory technique. Psychophysiological arousal as indexed by non-metabolic heart rate, self-reported emotions and situational information were assessed during 24-h recordings in 70 healthy participants. The emotional state was used to trigger word list presentations on a minicomputer. Our results show that psychophysiological arousal at the time of encoding enhanced the recall of negative words in negative emotional conditions, whereas low psychophysiological arousal facilitated recall of positive words. In positive contexts, mood congruency was more prominent when arousal was low. These results demonstrate how automated experimentation with an ambulatory technique may help to assess emotional memory in real-world contexts, thus providing new methods for diverse fields of application.