Acute effects of a single dose of 2 mA of anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex on executive functions in patients with schizophrenia-A randomized controlled trial.

OBJECTIVE: Cognitive impairments are a frequent and difficult to treat symptom in patients with schizophrenia and the strongest predictor for a successful reintegration in occupational and everyday life. Recent research suggests transcranial direct current stimulation (tDCS) to enhance cognition in this patient group. However, the question regarding its acute effectiveness on executive functions remains largely unanswered. Here, we examined in a randomized, double blind, sham-controlled repeated-measures design the impact of tDCS on performance in several executive functions in patients with schizophrenia, schizoaffective disorder or acute transient psychotic disorder. METHODS: Patients (N = 48) were tested twice using standardized, well-constructed and clinically validated neuropsychological tests assessing verbal working memory, response inhibition, mental flexibility and problem solving. In session 1 they solely underwent the neuropsychological assessment, whereas in session 2 they additionally received 2 mA of anodal tDCS stimulation over the left dorsolateral prefrontal cortex (DLPFC), cathode right supraorbital ridge, or sham stimulation for 20 minutes. RESULTS: Patients of both groups were not able to correctly discriminate the type of stimulation received confirming the success of the blinding procedure. However, analyzing the whole sample the change in performance from session 1 to session 2 was the same in the verum as in the sham condition (all p >.5). Moreover, a subsequent exploratory analysis showed that performance in the response inhibition task was worse for patients that engaged in the task within 20 minutes after the end of the verum stimulation. CONCLUSION: Hence, 2 mA of anodal tDCS applied over the left DLPFC did not acutely enhance executive functions in patients with schizophrenia or related disorders but impaired performance in the response inhibition task shortly after. Future studies should continue to seek for effective stimulation configurations for this patient group. CLINICAL TRIAL REGISTRATION: The study is registered in the "Deutsches Register Klinischer Studien DRKS", German Clinical Trial Register and has been allocated the following number: DRKS00022126.

Visual N80 latency as a marker of neuropsychological performance in schizophrenia: Evidence for bottom-up cognitive models.

OBJECTIVE: Cognitive deficits and visual impairment in the magnocellular (M) pathway, have been independently reported in schizophrenia. The current study examined the association between neuropsychological (NPS) performance and visual evoked potentials (VEPs: N80/P1 to M- and P(parvocellular)-biased visual stimuli) in schizophrenia and healthy controls. METHODS: NPS performance and VEPs were measured in n = 44 patients and n = 34 matched controls. Standardized NPS-scores were combined into Domains and a PCA (Principal Component Analysis) generated Composite. Group differences were assessed via (M)ANOVAs, association between NPS and VEP parameters via PCA, Pearson's coefficient and bootstrapping. Logistic regression was employed to assess classification power. RESULTS: Patients showed general cognitive impairment, whereas group differences for VEP-parameters were non-significant. In patients, N80 latency across conditions loaded onto one factor with cognitive composite, showed significant negative correlations of medium effect sizes with NPS performance for M/P mixed stimuli and classified low and high performance with 70% accuracy. CONCLUSION: The study provides no evidence for early visual pathway impairment but suggests a heightened association between early visual processing and cognitive performance in schizophrenia. SIGNIFICANCE: Our results lend support to bottom-up models of cognitive function in schizophrenia and implicate visual N80 latency as a potential biomarker of cognitive deficits in schizophrenia.

Internet-based aftercare for patients with personality disorders and trauma-related disorders: A pilot study.

Preventing readmission after hospital discharge is a major issue with regard to the continuity of patients' recovery process and the financial burden on the healthcare system, but adequate aftercare services are lacking. Therefore, a pilot study was conducted to examine the feasibility and acceptability of an Internet-based aftercare program for patients with personality disorders (PD) and / or trauma-related disorders as well as to obtain a preliminary estimate of effects on symptomatology and readmission. Patients' satisfaction with the program and symptomatology (KPD-38, BDI-II) were assessed prior to hospital discharge (t1) and after three months of participation (t2). Log data on program utilization (i.e., logins, page hits, and chat use) were automatically assessed via server logs. N = 31 of 45 eligible patients consented to participate. 84% used the intervention at least once. The average duration of participation was 63 days (SD = 4.6). Patients attended on average 7.2 out of 12 group chat sessions (SD = 4.0). Findings indicate very high acceptance of and satisfaction with the intervention. Symptomatology on all outcomes was stable, no deteriorations could be observed. 20% reported readmission within the aftercare period. Efficacy and cost-effectiveness should be tested with a large-scale randomized controlled trial.

Deficient fear extinction memory in posttraumatic stress disorder.

BACKGROUND: Posttraumatic stress disorder (PTSD) might be maintained by deficient extinction memory. We used a cued fear conditioning design with extinction and a post-extinction phase to provoke the return of fear and examined the role of the interplay of amygdala, hippocampus and prefrontal regions. METHODS: We compared 18 PTSD patients with two healthy control groups: 18 trauma-exposed subjects without PTSD (nonPTSD) and 18 healthy controls (HC) without trauma experience. They underwent a three-day ABC-conditioning procedure in a functional magnetic resonance imaging scanner. Two geometric shapes that served as conditioned stimuli (CS) were presented in the context of virtual reality scenes. Electric painful stimuli were delivered after one of the two shapes (CS+) during acquisition (in context A), while the other (CS-) was never paired with pain. Extinction was performed in context B and extinction memory was tested in a novel context C. RESULTS: The PTSD patients showed significantly higher differential skin conductance responses than the non-PTSD and HC and higher differential amygdala and hippocampus activity than the HC in context C. In addition, elevated arousal to the CS+ during extinction and to the CS- throughout the experiment was present in the PTSD patients but self-reported differential valence or contingency were not different. During extinction recall, differential amygdala activity correlated positively with the intensity of numbing and ventromedial prefrontal cortex activity correlated positively with behavioral avoidance. CONCLUSIONS: PTSD patients show heightened return of fear in neural and peripheral measures. In addition, self-reported arousal was high to both danger (CS+) and safety (CS-) cues. These results suggest that a deficient maintenance of extinction and a failure to identify safety signals might contribute to PTSD symptoms, whereas non-PTSD subjects seem to show normal responses.

Reduced amygdala responsivity during conditioning to trauma-related stimuli in posttraumatic stress disorder.

Exaggerated conditioned fear responses and impaired extinction along with amygdala overactivation have been observed in posttraumatic stress disorder (PTSD). These fear responses might be triggered by cues related to the trauma through higher-order conditioning, where reminders of the trauma may serve as unconditioned stimuli (US) and could maintain the fear response. We compared arousal, valence, and US expectancy ratings and BOLD brain responses using fMRI in 14 traumatized persons with PTSD and 14 without PTSD (NPTSD) and 13 matched healthy controls (HC) in a differential aversive conditioning paradigm. The US were trauma-specific pictures for the PTSD and NPTSD group and equally aversive and arousing for the HC; the conditioned stimuli (CS) were graphic displays. During conditioning, the PTSD patients compared to the NPTSD and HC indicated higher arousal to the conditioned stimulus that was paired with the trauma picture (CS+) compared to the unpaired (CS-), increased dissociation during acquisition and extinction, and failure to extinguish the CS/US-association compared to NPTSD. During early and late acquisition, the PTSD patients showed a significantly lower amygdala activation to CS+ versus CS- and a negative interaction between activation in the amygdala and dorsolateral prefrontal cortex (PFC), while NPTSD and HC displayed a negative interaction between amygdala and medial PFC. These findings suggest maladaptive anticipatory coping with trauma-related stimuli in patients with PTSD, indicated by enhanced conditioning, with related abnormal amygdala reactivity and connectivity, and delayed extinction.

Characteristics of child maltreatment and their relation to dissociation, posttraumatic stress symptoms, and depression in adult psychiatric patients.

Little is known about the influence of particular characteristics of childhood maltreatment, such as developmental stage, relationship to the perpetrator, and nature of the trauma, on adult psychopathology. The effects of childhood maltreatment were assessed in adult psychiatric patients (N = 287) using self-rating scales and diagnostic checklists. Maltreatment was strongly associated with dissociation. This relationship was observed for all childhood developmental stages and was strongest when the perpetrator was outside the family. Dissociation was more strongly correlated with childhood emotional abuse and sexual harassment than with sexual or physical abuse. Childhood sexual abuse was found to be associated with symptoms of posttraumatic stress. The findings suggest that dissociation is a relatively specific consequence of childhood maltreatment that is largely independent of the familial relationship to the perpetrator or the child's developmental stage.

The validity and reliability of the German version of the Somatoform Dissociation Questionnaire (SDQ-20).

The present study investigated the validity of the German version of the Somatoform Dissociation Questionnaire (SDQ-20), a scale designed to measure somatoform dissociative symptoms. Somatoform dissociation involves physical manifestations of a dissociation of the personality and is considered a unique entity in the phenomenological spectrum of dissociation. The validity and reliability of the German version of the SDQ-20 was examined using a sample of 225 patients with (n = 39) and without dissociative disorders who were recruited from several in- and outpatient psychiatric clinics. Patients were assessed using structured diagnostic interviews; diagnostic checklists; and self-rating scales for dissociation, and posttraumatic stress. Patients with dissociative disorders reported significantly more (p < .001) somatoform dissociative symptoms than patients without dissociative disorders (criterion validity). Significant correlations (p < .001) were found between scores of somatoform dissociation, psychoform dissociation, posttraumatic stress symptoms, and traumatic childhood experiences (construct validity). Reliability was corroborated by a Cronbach's alpha coefficient of .91 and a test-retest correlation of .89. A component factor analysis suggested unidimensionality of the SDQ-20. In conclusion, the psychometric properties and cross-cultural validity of the German version of the SDQ-20 are excellent. Our results form the basis for the further study of somatoform dissociation in German-speaking populations.

The Bern psychopathology scale for the assessment of system-specific psychotic symptoms.

The translation from psychiatric core symptoms to brain functions and vice versa is a largely unresolved issue. In particular, the search for disorders of single brain regions explaining classical symptoms has not yielded the expected results. Based on the assumption that the psychopathology of psychosis is related to a functional imbalance of higher-order brain systems, the authors focused on three specific candidate brain circuitries, namely the language, and limbic and motor systems. These domains are of particular interest for understanding the disastrous communication breakdown during psychotic disorders. Core symptoms of psychosis were mapped on these domains by shaping their definitions in order to match the related brain functions. The resulting psychopathological assessment scale was tested for interrater reliability and internal consistency in a group of 168 psychotic patients. The items of the scale were reliable and a principal component analysis (PCA) was best explained by a solution resembling the three candidate systems. Based on the results, the scale was optimized as an instrument to identify patient subgroups characterized by a prevailing dysfunction of one or more of these systems. In conclusion, the scale is apt to distinguish symptom domains related to the activity of defined brain systems. PCA showed a certain degree of independence of the system-specific symptom clusters within the patient group, indicating relative subgroups of psychosis. The scale is understood as a research instrument to investigate psychoses based on a system-oriented approach. Possible immediate advantages in the clinical application of the understanding of psychoses related to system-specific symptom domains are also discussed.