Environmental drivers of increased ecosystem respiration in a warming tundra

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

[Complex PTSD following early-childhood trauma: emotion-regulation training as addition to the PTSD guideline]

BACKGROUND

Posttraumatic stress disorder (PTSD) symptoms in individuals who have experienced repeated trauma (sexual and/or physical) in early childhood can lead to problems associated with emotion regulation, interpersonal functioning and self-image. This so-called complex PTSD is often accompanied by a comorbid personality disorder. Although ptsd is associated with structural and functional abnormalities in emotion-regulation areas in the brain, it is not known whether complex PTSD shows similar abnormalities. Experts take the view that before individuals with complex PTSD are given appropriate therapy they should receive a course of emotion-regulation therapy such as the one tested by Zlotnick e.a. (1997) in a randomised controlled trial (RCT).  

AIM

To replicate Zlotnick's RCT in the Netherlands and to find out whether complex PTSD patients show specific structural and functional brain abnormalities and whether psychological recovery is linked to the 'normalisation' of these abnormalities.

METHOD

In a RCT with complex PTSD patients (n = 71) who had experienced trauma in early childhood, we compared normal individual treatment with treatment supported by 'Before and beyond', which consists of emotion-regulation therapy combined with cognitive group therapy. In a subsample (n= 33) we also performed an mri (repeated, n = 9) in which individuals were required to execute an emotional memory and attention task.

RESULTS

In complex PTSD, structural abnormalities in the brain seemed to be more extensive than in PTSD and brain activity in complex PTSD seemed to be strikingly different from the brain activity seen in PTSD patients who had experienced only single trauma. The results of the RCT indicate that 'Before and beyond' is a clinically meaningful treatment (with minimal drop-out) for complex PTSD patients with a variety of personality disorders. The psychological recovery of patients who received the emotion regulation and cognitive group treatment was associated with normalisation of brain function.

CONCLUSION

Treatment guidelines for ptsd patients cannot be applied directly and automatically to complex PTSD because there is no scientific evidence to justify such a step. The neurobiological profile of PTSD differs from that of complex PTSD. Patients with complex PTSD seem to react favourably to emotion regulation therapy. This treatment therefore could be a useful addition to the current PTSD guideline for this specific group. There is a need for further research that focuses on complex PTSD patients.

Can pharmacological and psychological treatment change brain structure and function in PTSD? A systematic review

While there is evidence of clinical improvement of posttraumatic stress disorder (PTSD) with treatment, its neural underpinnings are insufficiently clear. Moreover, it is unknown whether similar neurophysiological changes occur in PTSD specifically after child abuse, given its enduring nature and the developmental vulnerability of the brain during childhood. We systematically reviewed PTSD treatment effect studies on structural and functional brain changes from PubMed, EMBASE, PsycINFO, PILOTS and the Cochrane Library. We included studies on adults with (partial) PTSD in Randomized Controlled Trials (RCT) or pre-post designs (excluding case studies) on pharmacotherapy and psychotherapy. Risk of bias was evaluated independently by two raters. Brain coordinates and effect sizes were standardized for comparability. We included 15 studies (6 RCTs, 9 pre-post), four of which were on child abuse. Results showed that pharmacotherapy improved structural abnormalities (i.e., increased hippocampus volume) in both adult-trauma and child abuse related PTSD (3 pre-post studies). Functional changes were found to distinguish between groups. Adult-trauma PTSD patients showed decreased amygdala and increased dorsolateral prefrontal activations post-treatment (4 RCTs, 5 pre-post studies). In one RCT, child abuse patients showed no changes in the amygdala, but decreased dorsolateral prefrontal, dorsal anterior cingulate and insula activation post-treatment. In conclusion, pharmacotherapy may reduce structural abnormalities in PTSD, while psychotherapy may decrease amygdala activity and increase prefrontal, dorsal anterior cingulate and hippocampus activations, that may relate to extinction learning and re-appraisal. There is some evidence for a distinct activation pattern in child abuse patients, which clearly awaits further empirical testing.

Evidence-based treatment for adult women with child abuse-related Complex PTSD: a quantitative review

INTRODUCTION

Effective first-line treatments for posttraumatic stress disorder (PTSD) are well established, but their generalizability to child abuse (CA)-related Complex PTSD is largely unknown.

METHOD

A quantitative review of the literature was performed, identifying seven studies, with treatments specifically targeting CA-related PTSD or Complex PTSD, which were meta-analyzed, including variables such as effect size, drop-out, recovery, and improvement rates.

RESULTS

Only six studies with one or more cognitive behavior therapy (CBT) treatment conditions and one with a present centered therapy condition could be meta-analyzed. RESULTS indicate that CA-related PTSD patients profit with large effect sizes and modest recovery and improvement rates. Treatments which include exposure showed greater effect sizes especially in completers' analyses, although no differential results were found in recovery and improvement rates. However, results in the subgroup of CA-related Complex PTSD studies were least favorable. Within the Complex PTSD subgroup, no superior effect size was found for exposure, and affect management resulted in more favorable recovery and improvement rates and less drop-out, as compared to exposure, especially in intention-to-treat analyses.

CONCLUSION

Limited evidence suggests that predominantly CBT treatments are effective, but do not suffice to achieve satisfactory end states, especially in Complex PTSD populations. Moreover, we propose that future research should focus on direct comparisons between types of treatment for Complex PTSD patients, thereby increasing generalizability of results.

Increased anterior cingulate cortex and hippocampus activation in Complex PTSD during encoding of negative words

Post-traumatic stress disorder (PTSD) is associated with impaired memory performance coupled with functional changes in brain areas involved in declarative memory and emotion regulation. It is not yet clear how symptom severity and comorbidity affect neurocognitive functioning in PTSD. We performed a functional magnetic resonance imaging (fMRI) study with an emotional declarative memory task in 28 Complex PTSD patients with comorbid depressive and personality disorders, and 21 healthy non-trauma-exposed controls. In Complex PTSD patients--compared to controls--encoding of later remembered negative words vs baseline was associated with increased blood oxygenation level dependent (BOLD) response in the left ventral anterior cingulate cortex (ACC) and dorsal ACC extending to the dorsomedial prefrontal cortex (dmPFC) together with a trend for increased left hippocampus activation. Patients tended to commit more False Alarms to negative words compared to controls, which was associated with enhanced left ventrolateral prefrontal and orbitofrontal cortex (vlPFC/OFC) responses. Severity of child abuse was positively correlated with left ventral ACC activity and severity of depression with (para) hippocampal and ventral ACC activity. Presented results demonstrate functional abnormalities in Complex PTSD in the frontolimbic brain circuit also implicated in fear conditioning models, but generally in the opposite direction, which may be explained by severity of the trauma and severity of comorbid depression in Complex PTSD.

Treatment compliance and effectiveness in complex PTSD patients with co-morbid personality disorder undergoing stabilizing cognitive behavioral group treatment: a preliminary study

BACKGROUND

In the empirical and clinical literature, complex posttraumatic stress disorder (PTSD) and personality disorders (PDs) are suggested to be predictive of drop-out or reduced treatment effectiveness in trauma-focused PTSD treatment.

OBJECTIVE

In this study, we aimed to investigate if personality characteristics would predict treatment compliance and effectiveness in stabilizing complex PTSD treatment.

METHOD

In a randomized controlled trial on a 20-week stabilizing group cognitive behavioral treatment (CBT) for child-abuse-related complex PTSD, we included 71 patients of whom 38 were randomized to a psycho-educational and cognitive behavioral stabilizing group treatment. We compared the patients with few PD symptoms (adaptive) (N=14) with the non-adaptive patients (N=24) as revealed by a cluster analysis.

RESULTS

We found that non-adaptive patients compared to the adaptive patients showed very low drop-out rates. Both non-adaptive patients, classified with highly different personality profiles "withdrawn" and "aggressive," were equally compliant. With regard to symptom reduction, we found no significant differences between subtypes. Post-hoc, patients with a PD showed lower drop-out rates and higher effect sizes in terms of complex PTSD severity, especially on domains that affect regulation and interpersonal problems.

CONCLUSIONS

Contrary to our expectations, these preliminary findings indicate that this treatment is well tolerated by patients with a variety of personality pathology. Larger sample sizes are needed to study effectiveness for subgroups of complex PTSD patients.

Treatment effects on insular and anterior cingulate cortex activation during classic and emotional Stroop interference in child abuse-related complex post-traumatic stress disorder

BACKGROUND

Functional neuroimaging studies have shown increased Stroop interference coupled with altered anterior cingulate cortex (ACC) and insula activation in post-traumatic stress disorder (PTSD). These brain areas are associated with error detection and emotional arousal. There is some evidence that treatment can normalize these activation patterns.

METHOD

At baseline, we compared classic and emotional Stroop performance and blood oxygenation level-dependent responses (functional magnetic resonance imaging) of 29 child abuse-related complex PTSD patients with 22 non-trauma-exposed healthy controls. In 16 of these patients, we studied treatment effects of psycho-educational and cognitive behavioural stabilizing group treatment (experimental treatment; EXP) added to treatment as usual (TAU) versus TAU only, and correlations with clinical improvement.

RESULTS

At baseline, complex PTSD patients showed a trend for increased left anterior insula and dorsal ACC activation in the classic Stroop task. Only EXP patients showed decreased dorsal ACC and left anterior insula activation after treatment. In the emotional Stroop contrasts, clinical improvement was associated with decreased dorsal ACC activation and decreased left anterior insula activation.

CONCLUSIONS

We found further evidence that successful treatment in child abuse-related complex PTSD is associated with functional changes in the ACC and insula, which may be due to improved selective attention and lower emotional arousal, indicating greater cognitive control over PTSD symptoms.

Seasonal climate manipulations have only minor effects on litter decomposition rates and N dynamics but strong effects on litter P dynamics of sub-arctic bog species

Litter decomposition and nutrient mineralization in high-latitude peatlands are constrained by low temperatures. So far, little is known about the effects of seasonal components of climate change (higher spring and summer temperatures, more snow which leads to higher winter soil temperatures) on these processes. In a 4-year field experiment, we manipulated these seasonal components in a sub-arctic bog and studied the effects on the decomposition and N and P dynamics of leaf litter of Calamagrostis lapponica, Betula nana, and Rubus chamaemorus, incubated both in a common ambient environment and in the treatment plots. Mass loss in the controls increased in the order Calamagrostis < Betula < Rubus. After 4 years, overall mass loss in the climate-treatment plots was 10 % higher compared to the ambient incubation environment. Litter chemistry showed within each incubation environment only a few and species-specific responses. Compared to the interspecific differences, they resulted in only moderate climate treatment effects on mass loss and these differed among seasons and species. Neither N nor P mineralization in the litter were affected by the incubation environment. Remarkably, for all species, no net N mineralization had occurred in any of the treatments during 4 years. Species differed in P-release patterns, and summer warming strongly stimulated P release for all species. Thus, moderate changes in summer temperatures and/or winter snow addition have limited effects on litter decomposition rates and N dynamics, but summer warming does stimulate litter P release. As a result, N-limitation of plant growth in this sub-arctic bog may be sustained or even further promoted.

Stabilizing group treatment for complex posttraumatic stress disorder related to child abuse based on psychoeducation and cognitive behavioural therapy: a multisite randomized controlled trial

BACKGROUND

Evidence-based treatments for complex posttraumatic stress disorder (PTSD) related to childhood abuse are scarce. This is the first randomized controlled trial to test the efficacy of psycho-educational and cognitive behavioural stabilizing group treatment in terms of both PTSD and complex PTSD symptom severity.

METHODS

Seventy-one patients with complex PTSD and severe comorbidity (e.g., 74% axis II comorbidity) were randomly assigned to either a 20-week group treatment in addition to treatment as usual or to treatment as usual only. Primary outcome measures were the Davidson trauma scale (DTS) for PTSD and the structured interview for disorders of extreme stress (SIDES) for complex PTSD symptoms. Statistical analysis was conducted in the intention-to-treat (ITT) and in the completer sample. Subjects were considered responders when scoring at 20 weeks at least 1 standard deviation below pretest findings.

RESULTS

The 16% attrition was relatively low. After 20 weeks, the experimental condition (large effect sizes) and control condition (medium effect sizes) both showed significant decreases on the DTS and SIDES, but differences between the conditions were not significant. The secondary responder analysis (ITT) revealed significantly more responders on the DTS (45 vs. 21%), but not on the SIDES (61 vs. 42%).

CONCLUSIONS

Adding psycho-educational and cognitive behavioural stabilizing group treatment for complex PTSD related to child abuse to treatment as usual showed an equivocal outcome. Patients in both conditions improved substantially during stabilizing treatment, and while significant superiority on change scores was absent, responder analysis suggested clinical meaningfulness of adding group treatment.

Clinical phenomenology of childhood abuse-related complex PTSD in a population of female patients: patterns of personality disturbance

OBJECTIVE

Complex posttraumatic stress disorder (PTSD) involves a variety of personality disturbances presumed to result from repeated interpersonal trauma such as child abuse. As Complex PTSD patients are a heterogeneous population, we searched for clinically relevant personality-based subtypes.

METHOD

This study used a cluster analysis of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), Axis II features within a sample of 71 female outpatients with systematically assessed child abuse-related Complex PTSD.

RESULTS

Two main subtypes were found: adaptive and nonadaptive. The latter was further differentiated into withdrawn, alienated, suffering, and aggressive subtypes, characterized by different levels of introversion and disinhibition. Among the nonadaptive subtypes, the severity of Complex PTSD symptoms was lowest in the withdrawn (introverted only) subtype. The subtypes differed in their level of dissociation and depression but did not differ regarding PTSD symptoms, trauma history, or parental bonding characteristics.

CONCLUSION

Confirming earlier findings, our study found personality-based Complex PTSD subtypes, which could implicate differential treatment needs and results.

Reduced anterior cingulate and orbitofrontal volumes in child abuse-related complex PTSD

OBJECTIVE

Classic posttraumatic stress disorder (PTSD) is associated with smaller hippocampus, amygdala, and anterior cingulate cortex (ACC) volumes. We investigated whether child abuse-related complex PTSD--a severe form of PTSD with affect dysregulation and high comorbidity--showed similar brain volume reductions.

METHOD

We used voxel-based morphometry to measure gray matter concentrations in referred outpatients with child abuse-related complex PTSD (n = 31) compared to matched healthy nontraumatized controls (n = 28). Complex PTSD was diagnosed using the Structured Clinical Interview for DSM-IV-TR and the Structured Clinical Interview for Disorders of Extreme Stress. All respondents were scanned on a 1.5-T magnetic resonance system at the VU Medical Center, Amsterdam, The Netherlands, between September 2005 and February 2006.

RESULTS

As was hypothesized, patients with child abuse-related complex PTSD showed reductions in gray matter concentration in right hippocampus (P(SVC corrected) = .04) and right dorsal ACC (P(SVC corrected) = .02) compared to controls. In addition, a reduction in gray matter concentration in the right orbitofrontal cortex (OFC) was found. Severity of child abuse and PTSD-hyperarousal correlated negatively with ACC volume. Impulsivity correlated negatively with hippocampus volume, and anger, with hippocampus and OFC volume. Comorbidity of borderline personality disorder--compared to comorbid cluster C personality disorder--accounted for more extensive reductions in the ACC and OFC volume.

CONCLUSIONS

In complex PTSD, not only the hippocampus and the ACC but also the OFC seem to be affected, even in the absence of comorbid borderline personality disorder. These results suggest that neural correlates of complex PTSD are more severe than those of classic PTSD.

Stabilizing group treatment for Complex Posttraumatic Stress Disorder related to childhood abuse based on psycho-education and cognitive behavioral therapy: a pilot study

OBJECTIVE

This study tests a Stabilizing Group Treatment protocol, designed for the management of the long-term sequelae of child abuse, that is, Complex Posttraumatic Stress Disorder (Complex PTSD). Evidence-based treatment for this subgroup of PTSD patients is largely lacking. This stabilizing treatment aims at improving Complex PTSD using psycho-education and cognitive behavioral interventions.

METHOD

Thirty-six patients with a history of childhood abuse, Complex PTSD and severe co-morbidity entered a 20-week treatment with pre-, post-, and follow-up-assessments.

RESULTS

Improvement was found for PTSD and borderline symptoms. Post-treatment 64% and after 6 months 78% of patients no longer met criteria for Complex PTSD.

CONCLUSIONS

This open study indicates both the feasibility of investigating treatment outcome and the initial efficacy of stabilizing group treatment in severely ill patients with Complex PTSD related to childhood abuse.

Increased activation of the left hippocampus region in Complex PTSD during encoding and recognition of emotional words: a pilot study

To gain insight into memory disturbances in Complex Posttraumatic Stress Disorder (Complex PTSD), we investigated declarative memory function and medial temporal lobe activity in patients and healthy non-traumatized controls. A case-control study was performed in nine patients with Complex PTSD and nine controls. All respondents performed a declarative memory task with neutral and emotional, negative words during functional magnetic resonance imaging. Memory performance of neutral words was impaired in Complex PTSD with a relative conservation of recall of negative words. Deep encoding of later remembered negative words, as well as correct recognition of negative words and false alarms, was associated with an enhanced Blood Oxygenation Level Dependent (BOLD) response in the left hippocampus extending into the parahippocampal gyrus of Complex PTSD patients compared with controls. Post-hoc volumetric comparisons did not reveal significant anatomical differences in the medial temporal lobe between Complex PTSD patients and controls. We conclude that in Complex PTSD preferential recall of negative words is associated with increased activation in the left hippocampus and parahippocampal gyrus during both successful and false recall. These findings support a model of an abnormally functioning hippocampus in Complex PTSD.

[Stabilisation therapy as an answer to complex post-traumatic stress disorder. Diagnosis, treatment and research in women abused in childhood with a complex post-traumatic stress disorder]

Complex post-traumatic stress disorder resulting from traumatic experiences in childhood includes not only the customary post-traumatic stress disorder symptoms such as intrusions, avoidance and hyperarousal, but it also includes affect-dysregulation, dissociation, problems with self-image, relationships, interpretation and somatisation. The specialist literature expresses some support for stabilisation treatment. Preliminary results of a pilot study that evaluated a stabilisation course with a psycho-educational and cognitive behavioural content indicate that a course of that kind, if linked to research, is both feasible and effective. We therefore believe that further research by means of a randomized controlled trial is warranted.

Fructans interact strongly with model membranes

Bacterial fructans with a high degree of polymerisation cause a very large increase in surface pressure of lipid monolayers at the air-water interface with a broad range of lipids, including phosphatidylethanolamine and several types of phosphatidylcholines. The surface active effect of fructans contrasts strongly with the maximal effects observed for trehalose, sucrose and glucose under comparable conditions (20 and 0.6 mN/m for fructans and the other sugars, respectively). The results demonstrate a profound and specific membrane interaction of the fructans which is probably very different from the effect of the smaller carbohydrates. The fructan concentrations used in this study are within the physiological range observed in fructan-accumulating plants. The suggested water-stress protective effect of fructans may be induced by membrane-fructan interaction which prevent lipid condensation and phase transitions to take place.