Larissa Wolkenstein

Amelioration of Cognitive Control in Depression by Transcranial Direct Current Stimulation

BACKGROUND Deficient cognitive control over emotional distraction is a central characteristic of major depressive disorder (MDD). Hypoactivation of the dorsolateral prefrontal cortex (dlPFC) has been linked with this deficit. In this study, we aimed to enhance the activity of the dlPFC in MDD patients by anodal transcranial direct current stimulation (tDCS) and thus ameliorate cognitive control. METHODS In a double-blinded, balanced, randomized, sham-controlled crossover trial, we determined the effect of a single-session tDCS to the left dlPFC on the cognitive control in 22 MDD patients and 22 healthy control subjects. To assess the cognitive control, we used a delayed response working memory task with pictures of varying content (emotional vs. neutral) presented during the delay period. RESULTS Emotional pictures presented during the delay period impaired accuracy and response time of patients with MDD, indicating an attentional bias for emotional stimuli. Anodal tDCS to the dlPFC was associated with an enhanced working memory performance both in patients and control subjects. Specifically in subjects with MDD, the attentional bias was completely abolished by anodal tDCS. CONCLUSIONS The present study demonstrates that anodal tDCS applied to the left dlPFC improves deficient cognitive control in MDD. Based on these data, tDCS might be suitable to support the effects of behavioral training to enhance cognitive control in MDD.

Is impaired set-shifting a feature of ''pure'' anorexia nervosa? Investigating the role of depression in set-shifting ability in anorexia nervosa and unipolar depression

Impaired set-shifting has been reported in patients with anorexia nervosa (AN) and in patients with affective disorders, including major depression. Due to the prevalent comorbidity of major depression in AN, this study aimed to examine the role of depression in set-shifting ability. Fifteen patients with AN without a current comorbid depression, 20 patients with unipolar depression (UD) and 35 healthy control participants were assessed using the Trail Making Test (TMT), the Wisconsin Card Sorting Test (WCST) and a Parametric Go/No-Go Test (PGNG). Set-shifting ability was intact in patients with AN without a comorbid depression. However, patients with UD performed significantly poorer in all three tasks compared to AN patients and in the TMT compared to healthy control participants. In both patient groups, set-shifting ability was moderately negatively correlated with severity of depressive symptoms, but was unrelated to BMI and severity of eating disorder symptoms in AN patients. Our results suggest a pivotal role of comorbidity for neuropsychological functioning in AN. Impairments of set-shifting ability in AN patients may have been overrated and may partly be due to comorbid depressive disorders in investigated patients.

Targeting the biased brain: non-invasive brain stimulation to ameliorate cognitive control

Non-invasive brain stimulation has become important for the investigation of healthy and impaired neuronal functioning. Moreover, non-invasive brain stimulation has emerged as a new means of psychiatric treatment, although the mechanisms of action are still not understood and the optimal mode of application is still under development. Dysfunctional cognitive control is a central characteristic of various psychiatric disorders and is associated with dysregulations of prefrontal cortex activity and biased information processing. With non-invasive brain stimulation, enhancement and reduction of prefrontal cortex activity were shown to ameliorate and impair cognitive control, respectively. These findings suggest a neurocognitive mechanism of therapeutic effects and that non-invasive brain stimulation can be combined with training to target dysfunctional cognitive control and related clinical symptomatology. Nevertheless, the intra-individual and inter-individual diversity of neurocognitive processes, the multiplicity of possible stimulation parameters, and the complexity of interactions between those factors pose considerable challenges for interpretation of these findings and their clinical application.

Cognitive emotion regulation in euthymic bipolar disorder

BACKGROUND Based on findings indicating increased stress reactivity and prolonged stress recovery in individuals with bipolar disorder (BD), it has been proposed that emotion regulation (ER) deficits lie at the core of this disorder. Recent studies show an increased use of maladaptive ER strategies and a decreased use of adaptive ER strategies in BD. Whether this pattern is merely a correlate of affective episodes or might be a stable characteristic of BD, however, remains to be explored. In addition, it is unclear whether these deficits in ER are specific to people with a history of BD. METHODS We examined whether euthymic BD individuals differ from healthy controls (HC) and individuals with a history of Major Depressive Disorder (MDD) with respect to the cognitive ER strategies they habitually use (CERQ) in response to negative affect. The sample consisted of 42 bipolar patients, 43 patients with MDD and 39 HC. RESULTS Compared to HC, euthymic BD and MDD individuals reported increased use of rumination, catastrophizing, and self-blame alongside decreased use of positive reappraisal, and putting into perspective. No differences were found between BD and MDD groups. LIMITATIONS These findings are based on self-reports reflecting the habitual use of ER-strategies. The use of more objective methods and the examination of the spontaneous use of ER-strategies in euthymic BD would be desirable. CONCLUSIONS Deficits in the habitual use of ER strategies may characterize BD and MDD individuals even outside of an acute episode and thereby play a role in the recurrence of affective disorders.

Keep Calm and Carry On: Improved Frustration Tolerance and Processing Speed by Transcranial Direct Current Stimulation (tDCS)

Cognitive control (CC) of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS) has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC) can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT) that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.

The Hypomania Checklist-32 and the Mood Disorder Questionnaire as screening tools — going beyond samples of purely mood-disordered patients

BACKGROUND Bipolar disorders are often not recognized. Several screening tools have been developed, e.g., the Hypomania Checklist-32 (HCL-32) and the Mood Disorder Questionnaire (MDQ) to improve this situation. Whereas the German HCL-32 has been used in non-clinical samples, neither the HCL-32 nor the MDQ has been validated in German samples of mood-disordered patients. Additionally, hardly any prior study has included patients with non-mood disorders or has considered potential effects of comorbid conditions. Therefore the goal of this study was to test the validity of both scales in a diverse patient sample while also taking into account psychiatric comorbidity. METHOD A multi-site study was conducted involving seven centers. Patients (n=488) completed the HCL-32 and MDQ and were independently interviewed with the Structured Clinical Interview for DSM (SCID). RESULTS Sensitivity for bipolar I was similar for HCL-32 and MDQ (.88 and .84) but slightly different for bipolar II (.90 and .83), specificity, however, was higher for MDQ. In general, a comorbid condition led to increased scores in both tools regardless of whether the primary diagnosis was bipolar or not. LIMITATIONS AND DISCUSSION: Although we included not just mood-disordered patients, detailed subgroup analyses for all diagnostic categories were not possible due to sample sizes. In summary, HCL-32 and MDQ seem fairly comparable in detecting bipolar disorders although their effectiveness depends on the goal of the screening, psychiatric comorbidity, and potentially the setting.

Specificity of jumping to conclusions and attributional biases: A comparison between patients with schizophrenia, depression, and anorexia nervosa

Introduction. The knowledge of the specificity of cognitive biases in psychiatric disorders is important in order to develop disorder-specific cognitive models and therapies. This cross-sectional study aimed to investigate the specificity of jumping to conclusions (JTC) and attributional biases (AB) for patients with schizophrenia. Methods. Twenty patients with paranoid schizophrenia were compared with patients with depression (n=20) and with anorexia nervosa (n=15) and nonclinical controls (n=55). All participants were administered a modified version of the beads task (JTC), a revised German version of the Internal, Personal, and Situational Attributions Questionnaire (AB), and several symptom and neurocognitive measures. Results. The proportion of patients with JTC bias in the schizophrenia group was, at the descriptive level, higher than in the depression and the anorexia groups. Regarding AB, the schizophrenia group showed a significantly stronger externalising but not personalising bias than the clinical control groups. Neither JTC nor attributional biases were significantly associated with delusions in general or persecutory delusion. Conclusions. We found evidence for the specificity of an externalising bias for paranoid schizophrenia. Concerning JTC bias the evidence was less clear. Whether the modification of those biases through psychological interventions would have an effect on psychopathology should be investigated in the context of clinical trials.

Emotional Distraction and Bodily Reaction: Modulation of Autonomous Responses by Anodal tDCS to the Prefrontal Cortex.

Prefrontal electric stimulation has been demonstrated to effectively modulate cognitive processing. Specifically, the amelioration of cognitive control (CC) over emotional distraction by transcranial direct current stimulation (tDCS) points toward targeted therapeutic applications in various psychiatric disorders. In addition to behavioral measures, autonomous nervous system (ANS) responses are fundamental bodily signatures of emotional information processing. However, interactions between the modulation of CC by tDCS and ANS responses have received limited attention. We here report on ANS data gathered in healthy subjects that performed an emotional CC task parallel to the modulation of left prefrontal cortical activity by 1 mA anodal or sham tDCS. Skin conductance responses (SCRs) to negative and neutral pictures of human scenes were reduced by anodal as compared to sham tDCS. Individual SCR amplitude variations were associated with the amount of distraction. Moreover, the stimulation-driven performance- and SCR-modulations were related in form of a quadratic, inverse-U function. Thus, our results indicate that non-invasive brain stimulation (i.e., anodal tDCS) can modulate autonomous responses synchronous to behavioral improvements, but the range of possible concurrent improvements from prefrontal stimulation is limited. Interactions between cognitive, affective, neurophysiological, and vegetative responses to emotional content can shape brain stimulation effectiveness and require theory-driven integration in potential treatment protocols.

Current alcohol use and risk for hypomania in male students: generally more or more binging?

BACKGROUND Alcohol use disorders and bipolar disorder are highly comorbid. Some studies suggest that alcohol abuse or misuse might even precede the onset of bipolar disorder, but few studies have looked at the daily drinking pattern beyond diagnostic categories. We therefore examined if risk for hypomania is associated with a specific drinking pattern when using a calendar-based interview. METHOD A total of 120 students who completed the Hypomanic Personality Scale were independently interviewed with the FORM 90 to assess daily drinking and the Composite Diagnostic Interview to derive Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnoses. RESULTS Conducting regression analyses, we found that an alcohol-related disorder was related to the amount and frequency of drinking, as expected. Risk for hypomania was specifically related to an unstable drinking pattern and binge drinking, but not generally higher consumption. CONCLUSION Risk for hypomania was associated with unstable alcohol consumption and binge drinking, even after controlling for alcohol-related disorders. This supports the idea that instability in different areas of behavior is characteristic of vulnerability to hypomania.

Facial emotion recognition, theory of mind and the role of facial mimicry in depression

BACKGROUND This study examined whether acutely (aMDD) and remitted depressed patients (rMDD) show deficits in the two aspects of social cognition - facial emotion recognition (FER) and reasoning - when using ecologically valid material. Furthermore, we examined whether reduced facial mimicry mediates the association between depressive symptoms and FER, and whether FER deficits and reasoning deficits are associated. METHOD In 42 aMDD, 43 rMDD, and 39 healthy controls (HC) FER was assessed using stimuli from the Amsterdam Dynamic Facial Expression Set, reasoning by the Movie for the Assessment of Social Cognition. Furthermore, the activity of Zygomaticus Major and Corrugator supercilii were recorded. RESULTS aMDD recognized happy faces less accurately, were less confident recognizing happiness and anger and found it more difficult to recognize happiness, anger and fear than HC. rMDD were less confident recognizing anger and found it more difficult to recognize happiness, anger and fear than HC. Reduced mimicry did not explain FER deficits. aMDD but not rMDD showed impaired reasoning. LIMITATIONS The stimulus material was comparably easy to decode. Therefore, it is possible that the FER deficits of aMDD and rMDD patients are more pronounced than demonstrated in this study. CONCLUSIONS aMDD show deficits in FER and reasoning, whereas rMDD only show mild impairments in the recognition of emotional expressions. There must be other processes - besides mimicry - that serve the accurate recognition of emotional facial expressions.