What is the contribution of different cognitive biases and stressful childhood events to the presence and number of previous depressive episodes?

Attentional bias in individuals with depression and adverse childhood experiences: influence of the noradrenergic system?

RATIONALE

Major depressive disorder (MDD) is a severe mental disorder with affective, cognitive, and somatic symptoms. Mood congruent cognitive biases, including a negative attentional bias, are important for development, maintenance, and recurrence of depressive symptoms. MDD is associated with maladaptive changes in the biological stress systems such as dysregulations of central noradrenergic alpha2-receptors in the locus coeruleus-noradrenergic system, which can affect cognitive processes including attention. Patients with adverse childhood experiences (ACE), representing severe stress experiences in early life, might be particularly affected.

OBJECTIVES

With an experimental design, we aimed to gain further knowledge about the role of noradrenergic activity for attentional bias in MDD patients with and without ACE.

METHODS

We tested the effect of increased noradrenergic activity induced by the alpha2-receptor blocker yohimbine on attentional bias in a placebo-controlled repeated measures design. Four groups were included as follows: MDD patients with and without ACE, and healthy participants with and without ACE (total N = 128, all without antidepressant medication).

RESULTS

A significant effect of MDD on attentional bias scores of sad face pictures (p = .037) indicated a facilitated attentional processing of sad face pictures in MDD patients (compared to non-MDD individuals). However, we found no such effect of ACE. For attentional bias of happy face pictures, we found no significant effects of MDD and ACE. Even though a higher increase of blood pressure and salivary alpha-amylase following yohimbine compared to placebo indicated successful noradrenergic stimulation, we found no significant effects of yohimbine on attentional bias of happy or sad face pictures.

CONCLUSIONS

Our results are consistent with the hypothesis of a negative attentional bias in MDD patients. However, as we found no effect of ACE or yohimbine, further research is needed to understand the mechanisms by which ACE increases the risk of MDD and to understand the biological basis of the MDD-related negative attentional bias.

Negative memory bias as a transdiagnostic cognitive marker for depression symptom severity

BACKGROUND

Negative memory bias is a strong risk factor for the development and maintenance of depression. Recent evidence also found negative memory bias in other mental disorders. Here, we aim to: 1) assess the presence and strength of negative memory bias in a range of (comorbid) mental disorders, 2) investigate which disorder-specific symptoms are associated with negative memory bias, and 3) test whether negative memory bias might be a transdiagnostic mechanism.

METHODS

Negative memory bias was measured in patients with at least one diagnosis of a stress-related disorder (n = 86), a neurodevelopmental disorder (n = 53), or both (n = 68), and 51 controls. Depression, anxiety, attention-deficit/hyperactivity disorder, and autism spectrum disorder symptom severity was assessed using questionnaires. Groups were compared on negative memory bias and the associations between negative memory bias and symptom severity were made using linear regression models.

RESULTS

All patient groups showed stronger negative memory bias than the controls. Negative memory bias was individually associated with all symptom severity indices, but when added into a single model, only the association with depressive symptom severity remained. This persisted after controlling for diagnostic group.

LIMITATIONS

Due to the cross-sectional sectional study design, we could only look at the associations between negative memory bias and disorder-specific symptoms and not at the direction of the effects.

CONCLUSIONS

Negative memory bias is characteristic of a depressotypic processing style and present in different mental disorders. It might play a mechanistic role in the development of (subclinical) co-occurrence between mental disorders.

Emotional Biases and Recurrence in Major Depressive Disorder. Results of 2.5 Years Follow-Up of Drug-Free Cohort Vulnerable for Recurrence

An interesting factor explaining recurrence risk in Major Depressive Disorder (MDD) may be neuropsychological functioning, i.e., processing of emotional stimuli/information. Negatively biased processing of emotional stimuli/information has been found in both acute and (inconclusively) remitted states of MDD, and may be causally related to recurrence of depression. We aimed to investigate self-referent, memory and interpretation biases in recurrently depressed patients in remission and relate these biases to recurrence. We included 69 remitted recurrent MDD-patients (rrMDD-patients), 35-65 years, with ≥2 episodes, voluntarily free of antidepressant maintenance therapy for at least 4 weeks. We tested self-referent biases with an emotional categorization task, bias in emotional memory by free recall of the emotion categorization task 15 min after completing it, and interpretation bias with a facial expression recognition task. We compared these participants with 43 never-depressed controls matched for age, sex and intelligence. We followed the rrMDD-patients for 2.5 years and assessed recurrent depressive episodes by structured interview. The rrMDD-patients showed biases toward emotionally negative stimuli, faster responses to negative self-relevant characteristics in the emotional categorization, better recognition of sad faces, worse recognition of neutral faces with more misclassifications as angry or disgusting faces and less misclassifications as neutral faces (0.001 < p < 0.05). Of these, the number of misclassifications as angry and the overall performance in the emotional memory task were significantly associated with the time to recurrence (p ≤ 0.04), independent of residual symptoms and number of previous episodes. In a support vector machine data-driven model, prediction of recurrence-status could best be achieved (relative to observed recurrence-rate) with demographic and childhood adversity parameters (accuracy 78.1%; 1-sided p = 0.002); neuropsychological tests could not improve this prediction. Our data suggests a persisting (mood-incongruent) emotional bias when patients with recurrent depression are in remission. Moreover, these persisting biases might be mechanistically important for recurrence and prevention thereof.

Physical neglect during childhood alters white matter connectivity in healthy young males

BACKGROUND

Childhood adversity (CA) leads to greater vulnerability for psychopathology by causing structural as well as functional brain abnormalities. Recent findings on gray matter effects point towards the importance of identifying CA outcome as a function of different CA types, varying in the dimensions of threat and deprivation. Using diffusion tensor imaging, we investigate whether different forms of CA impact differently on white matter connectivity in a healthy cohort not confounded by other aspects of disease.

METHODS

In 120 healthy young males, we assessed different forms of maltreatment during childhood with the Childhood Trauma Questionnaire (CTQ). Fractional anisotropy (FA) and mean diffusivity (MD) images were generated and projected onto a white matter skeleton using tract-based spatial statistics. Correlational analysis between FA, MD, and CTQ subscores was then performed using voxelwise statistics.

RESULTS

Of all CTQ-subscores, only physical neglect (PN) predicted a decrease of FA but not MD in the bilateral anterior thalamic radiation around the middle frontal gyrus and the right inferior fronto-occipital fasciculus, the inferior longitudinal fasciculus, the cingulum and precuneus. Reduced FA in the posterior cingulum was related to the effects of PN during childhood on anxiety levels at trend level.

CONCLUSIONS

PN may have severe consequences and should be considered equally important to more active forms of abuse. FA changes, particularly in the cingulum, actually appear to a functional consequence and are linked to trait anxiety, a personality dimension that is suggested to be a transdiagnostic risk factor of affective disorders. Potentially this reveals a mechanistic chain that forms one pathyway from CA to disease.

ADHD symptoms in healthy adults are associated with stressful life events and negative memory bias

Stressful life events, especially Childhood Trauma, predict ADHD symptoms. Childhood Trauma and negatively biased memory are risk factors for affective disorders. The association of life events and bias with ADHD symptoms may inform about the etiology of ADHD. Memory bias was tested using a computer task in N = 675 healthy adults. Life events and ADHD symptoms were assessed using questionnaires. The mediation of the association between life events and ADHD symptoms by memory bias was examined. We explored the roles of different types of life events and of ADHD symptom clusters. Life events and memory bias were associated with overall ADHD symptoms as well as inattention and hyperactivity/impulsivity symptom clusters. Memory bias mediated the association of Lifetime Life Events, specifically Childhood Trauma, with ADHD symptoms. Negatively biased memory may be a cognitive marker of the effects of Childhood Trauma on the development and/or persistence of ADHD symptoms.

Refilling the half-empty glass--Investigating the potential role of the Interpretation Modification Paradigm for Depression (IMP-D)

BACKGROUND AND OBJECTIVES

Cognitive biases are known to cause and maintain depression. However, little research has been done on techniques targeting interpretation tendencies found in depression, despite the promising findings of anxiety studies. This paper presents two experiments, investigating the suitability of an Interpretation Modification Paradigm for Depression (IMP-D) in healthy individuals, which has already proven its effectiveness in anxiety (Beard & Amir, 2008). Different from other paradigms, the IMP-D aims at modifying an interpretation bias on response- and on a more implicit reaction time-level, making this task less susceptible to demand effects.

METHODS

The Word-Sentence Association Paradigm for Depression (Hindash & Amir, 2011) was modified and administered in healthy volunteers (experiment I: N = 81; experiment II: N = 105). To enhance a positive interpretation bias, endorsing benign and rejecting negative interpretations of ambiguous scenarios was reinforced through feedback. This intervention was compared to the opposite training (both experiments) and a control training (experiment II only).

RESULTS

Both experiments revealed a significant increase in bias towards benign interpretations on the level of overt decisions, while only in the first experiment a change was found on a reaction time level. These modifications are not reflected in group-differences in emotional vulnerability.

LIMITATIONS

Possible limitations regarding the reliability of inter-dependent response and reaction time measures are discussed.

CONCLUSIONS

The IMP-D is able to modify interpretation biases, but adaptations are required to maximize its beneficial effects.

Cognitive impairment in remitted and non-remitted depressive patients: A follow-up comparison between first and recurrent episodes

Cognitive impairment is a core symptom of depressive disorders associated with poor social function. New research is needed to analyze depression-related symptoms in cognitive impairment and to observe if they are reversible or not during clinical remission in patients with or without previous episodes. None of the previous studies has analyzed the differences between first and recurrent episodes in a long-term follow-up study related with remission state. The aim of our study was to compare cognitive performance and assess the impact of previous depressive episodes in a sample of patients in acute phase and in remission six month later. 79 depressive patients were assessed at baseline. The instruments used for clinical and cognitive assessment were: Hamilton Depression Rating Scale, Mini-Mental State Examination and the Clinical Global Impression Rating Scales, Trail Making Test parts A and B, Digital Span subtest of WAIS, Stroop Colour Word Test, Tower of London, Controlled Verbal Fluency Task, Semantic Verbal Fluency and Finger Tapping Test. A repeated measures MANCOVA with education as covariate was used. No differences were found at baseline between first episode and recurrent depressive patients. At six month, remitted patients scored significant better in TMT-A, TMT-B, Animals and Tower of London total time. Remitted first depressive patients scored significant worse than remitted recurrent depressive patients. The main finding of the study is the effect of remission on cognitive function despite previous episodes. However first episode remitted patients seemed to have poor access to long term memory than recurrent remitted patients.

Interaction of the 5-HTTLPR and childhood trauma influences memory bias in healthy individuals

The tendency to recall more negative and less positive information has been frequently related to the genetic susceptibility to depression. This memory bias may be associated with depression candidate genes especially in individuals who experienced stressful childhood events. The serotonin transporter gene, SLC6A4/5-HTT, regulates the reuptake of serotonin. The 5-HTTLPR polymorphism in the gene's promoter region has a short (S) and a long (L) allele, of which L contains a further SNP (rs25531), resulting in a triallelic polymorphism: La, Lg, and S. Both S and Lg result in increased serotonin signaling (to simplify, we refer to both alleles as 'S'), which in turn appears associated with depression vulnerability, specifically in individuals with stressful events. In non-depressed individuals (N=1083), we examined the interaction between the 5-HTTLPR genotype (LaLa, SLa, and SS) and stressful childhood events in association with explicit verbal memory bias (positive, negative). Two types of stressful childhood events were studied, namely childhood adverse events (e.g. parental loss) and interpersonal traumatic childhood events (e.g. abuse). Less positive memory bias was found for individuals with the SS genotype who had experienced interpersonal childhood traumatic events. No general association of genotype with memory bias was found, nor was there a significant interaction between genotype and childhood adverse events. Our results suggest that the depression-susceptibility genotype of the 5-HTTLPR is associated with depressive information processing styles when occurring in combination with traumatic childhood events. Tailoring treatment to specific risk profiles based on genetic susceptibility and childhood stress could be promising.

No evidence for the association between a polymorphism in the PCLO depression candidate gene with memory bias in remitted depressed patients and healthy individuals

The PCLO rs2522833 candidate polymorphism for depression has been associated to monoaminergic neurotransmission. In healthy and currently depressed individuals, the polymorphism has been found to affect activation of brain areas during memory processing, but no direct association of PCLO with memory bias was found. We hypothesized that the absence of this association might have been obscured by current depressive symptoms or genetically driven individual differences in reactivity to stressful events. Experiencing stressful childhood events fosters dysfunctional assumptions that are related to cognitive biases, and may modulate the predisposition for depression via epigenetic effects. The association between PCLO and memory bias, as well as interaction between PCLO and childhood events was studied in patients remitted from depression (N = 299), as well as a sample of healthy individuals (N = 157). The participants performed an emotional verbal memory task after a sad mood induction. Childhood trauma and adversity were measured with a questionnaire. The Genotype main effect, and Genotype by Childhood Events interaction were analyzed for memory bias in both samples. PCLO risk allele carrying remitted depressed patients did not show more negatively biased memory than non-risk allele carriers, not even patients with stressful childhood events. A similar pattern of results was found in healthy individuals. Memory bias may not be strongly associated with the PCLO rs2522833 polymorphism. We did not find any support for the PCLO-childhood events interaction, but the power of our study was insufficient to exclude this possibility.