Relationship between trait anxiety and health-related factors

Growing evidence indicates that anxious individuals are more likely to engage in unhealthy lifestyle behaviors associated with coronary heart disease. We examined the relationship of Trait Anxiety (T-Anx) with lifestyle behaviors and physiological variables in a sample of 34 college undergraduates scoring in the upper/lower quartiles on T-Anx (50% women). Participants were assessed for physiological variables (BP, BMI) and behaviors including cigarette smoking, activity/exercise level, alcohol intake, and sleep. High T-Anx participants smoked significantly more cigarettes, slept significantly fewer hours, and engaged in significantly less vigorous-intensity physical activity than low T-Anx participants. No significant differences between groups were noted on BP, BMI, overall activity level, or alcohol use. These findings provide evidence that high TAnx college-age individuals engage in unhealthy behaviors

Transcranial direct current stimulation impairs updating of avoidance-based associative learning

IntroductionExposure-based psychotherapies for the treatment of anxiety- and fear-based disorders rely on “corrective” associative learning. Namely the repeated confrontation with feared stimuli in the absence of negative outcomes allows the formation of new, corrected associations of safety, indicating that such stimuli no longer need to be avoided. Unfortunately, exposure-facilitated corrective learning tends to be bound by context and often poorly generalizes. One brain structure, the prefrontal cortex, is implicated in context-guided behavior and may be a relevant target for improving generalization of safety learning. Here, we tested whether inhibition of the left prefrontal cortex causally impaired updating of context-bound associations specifically or, alternatively, impaired updating of learned associations irrespective of contextual changes. Additionally, we tested whether prefrontal inhibition during corrective learning influenced subsequent generalization of associations to a novel context.MethodsIn two separate experiments, participants received either 10 min of 2 mA cathodal transcranial direct current stimulation (tDCS) over EEG coordinate F3 (Experiment 1 n = 9, Experiment 2 n = 22) or sham stimulation (Experiment 1 n = 10, Experiment 2 n = 22) while previously learned associations were reversed in the same or a different context from initial learning. Next, to assess generalization of learning, participants were asked to indicate which of the previously seen images they preferred in a novel, never seen before context.ResultsResults indicate that tDCS significantly impaired reversal irrespective of context in Experiment 2 only. When taking learning rate across trials into account, both experiments suggest that participants who received sham had the greatest learning rate when reversal occurred in a different context, as expected, whereas participants who received active tDCS in this condition had the lowest learning rate. However, active tDCS was associated with preferring the originally disadvantageous, but then neural stimulus after stimulus after reversal occurred in a different context in Experiment 1 only.DiscussionThese results support a causal role for the left prefrontal cortex in the updating of avoidance-based associations and encourage further inquiry investigating the use of non-invasive brain stimulation on flexible updating of learned associations

Abstract task sequence initiation deficit dissociates anxiety disorders from obsessive-compulsive disorder and healthy controls

In everyday life, humans carry out sequences of tasks. Such sequential tasks may be disrupted in those with obsessive-compulsive disorder (OCD). Symptoms such as compulsions often cause repetitions of tasks or sequences that disrupt daily living. Such disruptions have been observed experimentally and may be unique to OCD. Deficits in implicitly learned motor sequences have been observed in participants with OCD compared to those with anxiety disorders (ANX). However, the sequences performed in daily life are most often not implicit motor-only sequences. They require completing a series of tasks that do not depend on the motor actions always being the same, such as cooking, and thus could be considered abstract. We tested the hypothesis that OCD participants exhibit a deficit in abstract sequential task performance compared to healthy controls (HCs) and ANX. A transdiagnostic sample of participants with OCD, anxiety, and related disorders and healthy controls completed sequences of simple categorization tasks. Surprisingly, participants with OCD did not perform worse than HCs or ANX. However, ANX participants exhibited significantly higher reaction times throughout the task and at sequence initiation. Further, task switching, a measure of general cognitive control, was similar in ANX participants compared to healthy controls and OCD, suggesting that abstract sequential control was specifically altered in ANX while general cognitive control was preserved. These results implicate abstract sequential control deficits in individuals with anxiety disorders but not in OCD, and further suggest OCD behavior aligns more closely with implicit motor sequence deficits rather than dysfunctional abstract sequential control

Prediction of remission in obsessive compulsive disorder using a novel machine learning strategy

The study objective was to apply machine learning methodologies to identify predictors of remission in a longitudinal sample of 296 adults with a primary diagnosis of obsessive compulsive disorder (OCD). Random Forests is an ensemble machine learning algorithm that has been successfully applied to large-scale data analysis across vast biomedical disciplines, though rarely in psychiatric research or for application to longitudinal data. When provided with 795 raw and composite scores primarily from baseline measures, Random Forest regression prediction explained 50.8% (5000-run average, 95% bootstrap confidence interval [CI]: 50.3-51.3%) of the variance in proportion of time spent remitted. Machine performance improved when only the most predictive 24 items were used in a reduced analysis. Consistently high-ranked predictors of longitudinal remission included Yale-Brown Obsessive Compulsive Scale (Y-BOCS) items, NEO items and subscale scores, Y-BOCS symptom checklist cleaning/washing compulsion score, and several self-report items from social adjustment scales. Random Forest classification was able to distinguish participants according to binary remission outcomes with an error rate of 24.6% (95% bootstrap CI: 22.9-26.2%). Our results suggest that clinically-useful prediction of remission may not require an extensive battery of measures. Rather, a small set of assessment items may efficiently distinguish high- and lower-risk patients and inform clinical decision-making

Predicting course of illness in patients with severe obsessive-compulsive disorder.

ObjectiveFew data are available to inform clinical expectations about course and prognosis of severe obsessive-compulsive disorder (OCD). Such information is necessary to guide clinicians and to inform criteria for invasive interventions for severe and intractable OCD. This study sought to examine course and prospective predictors of a chronic course in patients with severe OCD over 5 years.MethodA selected subset of adults in the Brown Longitudinal Obsessive-Compulsive Study (BLOCS) was included. Adult BLOCS participants were enrolled between 2001 and 2006. All participants in the current study (N = 113) had DSM-IV OCD diagnosis, severe OCD symptoms at baseline, and at least 1 year of follow-up data.ResultsCox proportional hazard models were used to examine the general pattern of course in the severe OCD sample based on Longitudinal Interval Follow-Up Evaluation (LIFE) psychiatric status ratings, as well as test predictors of chronically severe course. Results indicated that approximately half of patients with severe OCD at baseline had illness drop to a moderate or lower range of severity during 5 years of follow-up (50.4%) and that marked improvement was rare after 3 years of severe illness. The only unique predictor of a more chronically severe course was patient report of ever having been housebound for a week or more due to OCD symptoms (P < .05).ConclusionsFindings of this study were 3-fold: (1) half of participants with severe OCD have symptom improvement over 5 years of follow-up, (2) the majority of participants that drop out of the severe range of symptom severity do so within the first 3 years of follow-up, and (3) patient-reported history of being housebound for 1 week or more due to OCD is a significant predictor of OCD's remaining severe over the 5-year follow-up