Thorsten Barnhofer

Autobiographical Memory Specificity and Emotional Disorder

The authors review research showing that when recalling autobiographical events, many emotionally disturbed patients summarize categories of events rather than retrieving a single episode. The mechanisms underlying such overgeneral memory are examined, with a focus on M. A. Conway and C. W. Pleydell-Pearces (2000) hierarchical search model of personal event retrieval. An elaboration of this model is proposed to account for overgeneral memory, focusing on how memory search can be affected by (a) capture and rumination processes, when mnemonic information used in retrieval activates ruminative thinking; (b) functional avoidance, when episodic material threatens to cause affective disturbance; and (c) impairment in executive capacity and control that limits an individuals ability to remain focused on retrieval in the face of distraction.

Mindfulness-based cognitive therapy as a treatment for chronic depression: A preliminary study.

This pilot study investigated the effectiveness of Mindfulness-Based Cognitive Therapy (MBCT), a treatment combining mindfulness meditation and interventions taken from cognitive therapy, in patients suffering from chronic-recurrent depression. Currently symptomatic patients with at least three previous episodes of depression and a history of suicidal ideation were randomly allocated to receive either MBCT delivered in addition to treatment-as-usual (TAU; N = 14 completers) or TAU alone (N = 14 completers). Depressive symptoms and diagnostic status were assessed before and after treatment phase. Self-reported symptoms of depression decreased from severe to mild levels in the MBCT group while there was no significant change in the TAU group. Similarly, numbers of patients meeting full criteria for depression decreased significantly more in the MBCT group than in the TAU group. Results are consistent with previous uncontrolled studies. Although based on a small sample and, therefore, limited in their generalizability, they provide further preliminary evidence that MBCT can be used to successfully reduce current symptoms in patients suffering from a protracted course of the disorder.

Problem Solving Deteriorates Following Mood Challenge in Formerly Depressed Patients With a History of Suicidal Ideation.

The authors divided 34 participants who had a history of depression into 2 groups, those having previous suicidal ideation or behavior (n=19) and those having no such symptoms (n=15), then compared the 2 groups with a group of participants who had no history of depression (n=22). Assessment of interpersonal problem-solving performance using the Means-Ends Problem-Solving (MEPS) task before and after a mood-induction procedure showed that only those formerly depressed people with a history of suicidal ideation shifted in MEPS performance, producing significantly less effective problem solutions following mood challenge, consistent with a differential activation account of vulnerability for recurrence of suicidal ideation and behavior. The deterioration in effectiveness following mood challenge was moderated by lack of specificity in autobiographical memory.

Mindfulness-Based Cognitive Therapy for Preventing Relapse in Recurrent Depression: A Randomized Dismantling Trial.

Objective: We compared mindfulness-based cognitive therapy (MBCT) with both cognitive psychological education (CPE) and treatment as usual (TAU) in preventing relapse to major depressive disorder (MDD) in people currently in remission following at least 3 previous episodes. Method: A randomized controlled trial in which 274 participants were allocated in the ratio 2:2:1 to MBCT plus TAU, CPE plus TAU, and TAU alone, and data were analyzed for the 255 (93%; MBCT = 99, CPE = 103, TAU = 53) retained to follow-up. MBCT was delivered in accordance with its published manual, modified to address suicidal cognitions; CPE was modeled on MBCT, but without training in meditation. Both treatments were delivered through 8 weekly classes. Results: Allocated treatment had no significant effect on risk of relapse to MDD over 12 months follow-up, hazard ratio for MBCT vs. CPE = 0.88, 95% CI [0.58, 1.35]; for MBCT vs. TAU = 0.69, 95% CI [0.42, 1.12]. However, severity of childhood trauma affected relapse, hazard ratio for increase of 1 standard deviation = 1.26 (95% CI [1.05, 1.50]), and significantly interacted with allocated treatment. Among participants above median severity, the hazard ratio was 0.61, 95% CI [0.34, 1.09], for MBCT vs. CPE, and 0.43, 95% CI [0.22, 0.87], for MBCT vs. TAU. For those below median severity, there were no such differences between treatment groups. Conclusion: MBCT provided significant protection against relapse for participants with increased vulnerability due to history of childhood trauma, but showed no significant advantage in comparison to an active control treatment and usual care over the whole group of patients with recurrent depression.

Effects of Mindfulness on Meta-Awareness and Specificity of Describing Prodromal Symptoms in Suicidal Depression

The authors examined the effects of mindfulness training on 2 aspects of mode of processing in depressed participants: degree of meta-awareness and specificity of memory. Each of these has been suggested as a maladaptive aspect of a mode of processing linked to persistence and recurrence of symptoms. Twenty-seven depressed participants, all of whom had experienced suicidal crises, described warning signs for their last crisis. These descriptions were blind-rated independently for meta-awareness and specificity. Participants were then randomly allocated to receive mindfulness-based cognitive therapy (MBCT) plus treatment as usual (TAU) or TAU alone, and retested after 3 months. Results showed that, although comparable at baseline, patients randomized to MBCT displayed significant posttreatment differences in meta-awareness and specificity compared with TAU patients. These results suggest that mindfulness training may enable patients to reflect on memories of previous crises in a detailed and decentered way, allowing them to relate to such experiences in a way that is likely to be helpful in preventing future relapses.

Effects of meditation on frontal alpha-asymmetry in previously suicidal individuals.

This study investigated the effects of a meditation-based treatment for preventing relapse to depression, mindfulness-based cognitive therapy (MBCT), on prefrontal &agr;-asymmetry in resting electroencephalogram (EEG), a biological indicator of affective style. Twenty-two individuals with a previous history of suicidal depression were randomly assigned to either MBCT (N=10) or treatment-as-usual (TAU, N=12). Resting electroencephalogram was measured before and after an 8-week course of treatment. The TAU group showed a significant deterioration toward decreased relative left-frontal activation, indexing decreases in positive affective style, while there was no significant change in the MBCT group. The findings suggest that MBCT can help individuals at high risk for suicidal depression to retain a balanced pattern of baseline emotion-related brain activation.

Retrieval of autobiographical memories: The mechanisms and consequences of truncated search

Five studies examined the extent to which autobiographical memory retrieval is hierarchical, whether a hierarchical search depends on central executive resources, and whether retrieving memories that are “higher” in the hierarchy impairs problem‐solving ability. The first study found that random generation (assessed using a button‐pressing task) was sensitive to changes in memory load (digit span). The second study showed that when participants fail to retrieve a target event, they respond with a memory that is higher up the hierarchy. The third study showed that memory is more generic only when participants use low imageable cues under cognitive load. The final two experiments showed that experimental manipulation of memory specificity affects problem solving (MEPS performance). The data are consistent with Conway and Pleydell‐Pearces hierarchical retrieval model of autobiographical memory, and suggest that overgeneral memory in nonclinical participants is associated with reduced executive capacity only when retrieval is “top‐down” (generative).

Cognitive reactivity mediates the relationship between neuroticism and depression

Although neuroticism has long been established as an important risk factor for depression, the mechanisms through which this temperamental predisposition translates into the occurrence of symptoms are still relatively unclear. This study investigated cognitive reactivity, i.e. the ease with which particular patterns of negative thinking are reactivated in response to mild low mood, as a potential mediator. Individuals with (N = 98) and without a previous history of depression (N = 83) who had provided neuroticism scores six years previously were assessed for cognitive reactivity and current symptoms of depression using self-report questionnaires. Tendencies to respond to mild low mood with ruminative thinking mediated the relation between neuroticism and current symptoms of depression in both groups. Reactivation of hopelessness and suicidal thinking occurred as an additional mediator only in those with a history of previous depression. The results suggest that neuroticism predisposes individuals to depression by generally increasing the likelihood of ruminative responses to low mood. In those with a history of depression in the past, neuroticism additionally increases risk of recurrence by facilitating reactivation of previously associated patterns such as suicidal thinking and hopelessness. These findings suggest potential targets for interventions to help preventing the occurrence, or recurrence of depression in those who due to their temperamental predisposition are at an increased risk.

Reflection, brooding, and suicidality: a preliminary study of different types of rumination in individuals with a history of major depression.

OBJECTIVE To examine the relationship between reflection, brooding, and suicidality in participants with a history of major depression. METHOD Participants were divided into three groups - those who had never been suicidal (N=11), suicide ideators (N=11), and suicide attempters (N=10). Participants completed the Ruminative Responses Scale to explore scores on the brooding and reflection subscales in each group. RESULTS There was a significant interaction between groups and type of self-focused thinking: suicide attempters more strongly endorsed brooding than reflection, whilst non-suicidal, but previously depressed individuals showed the reverse trend. Suicidal and non-suicidal groups differed significantly in levels of reflection, but did not differ significantly in levels of brooding. CONCLUSIONS Deficits in reflection appear to be linked to suicidality in major depression consistent with evidence of problem-solving deficits in these groups.

State Effects of Two Forms of Meditation on Prefrontal EEG Asymmetry in Previously Depressed Individuals

We investigated state effects of two forms of meditation on electroencephalography prefrontal α-asymmetry, a global indicator of approach versus withdrawal motivation and related affective state. A clinical series of previously depressed individuals were guided to practice either mindfulness breathing meditation (N = 8) or a form of meditation directly aimed at cultivating positive affect, loving kindness or metta meditation (N = 7). Prefrontal asymmetry was assessed directly before and after the 15-min meditation period. Results showed changes in asymmetry towards stronger relative left prefrontal activation, i.e., stronger approach tendencies, regardless of condition. Further explorations of these findings suggested that responses were moderated by participants’ tendencies to engage in ruminative brooding. Individuals high in brooding tended to respond to breathing meditation but not loving kindness meditation, while those low in brooding showed the opposite pattern. Comparisons with an additionally recruited “rest” group provided evidence suggesting that changes seen were not simply attributable to habituation. The results indicate that both forms of meditation practice can have beneficial state effects on prefrontal α-asymmetry and point towards differential indications for offering them in the treatment of previously depressed patients.