Structural alterations within cerebellar circuitry are associated with general liability for common mental disorders.

Accumulating mental-health research encourages a shift in focus toward transdiagnostic dimensional features that are shared across categorical disorders. In support of this shift, recent studies have identified a general liability factor for psychopathology-sometimes called the 'p factor'- that underlies shared risk for a wide range of mental disorders. Identifying neural correlates of this general liability would substantiate its importance in characterizing the shared origins of mental disorders and help us begin to understand the mechanisms through which the 'p factor' contributes to risk. Here we believe we first replicate the 'p factor' using cross-sectional data from a volunteer sample of 1246 university students, and then using high-resolution multimodal structural neuroimaging, we demonstrate that individuals with higher 'p factor' scores show reduced structural integrity of white matter pathways, as indexed by lower fractional anisotropy values, uniquely within the pons. Whole-brain analyses further revealed that higher 'p factor' scores are associated with reduced gray matter volume in the occipital lobe and left cerebellar lobule VIIb, which is functionally connected with prefrontal regions supporting cognitive control. Consistent with the preponderance of cerebellar afferents within the pons, we observed a significant positive correlation between the white matter integrity of the pons and cerebellar gray matter volume associated with higher 'p factor' scores. The results of our analyses provide initial evidence that structural alterations in corticocerebellar circuitry supporting core functions related to the basic integration, coordination and monitoring of information may contribute to a general liability for common mental disorders.

Memory and memory confidence in obsessive-compulsive disorder.

Pathological doubt, often found in individuals with obsessive-compulsive disorder (OCD), has been theoretically linked to memory deficits, but empirical evidence for such deficits has been mixed. In contrast, many studies suggest that individuals with OCD have low confidence in their memories. The present study aimed to build upon previous research by measuring memory accuracy and confidence in OCD using ecologically valid, idiographically-selected stimuli. Individuals with OCD (OCs), anxious controls (ACs), and nonanxious controls (NACs) were exposed to a set of objects that the OCs had identified as safe, unsafe, or neutral. Participants were then asked to recall as many objects as possible and to rate their confidence in each memory. This process was repeated 6 times, using the same stimuli for each trial. Contrary to hypothesis, no group differences emerged in memory accuracy. However, OCs' memory confidence for unsafe objects showed a progressive decline over repeated trials. This pattern was not observed among NACs or ACs. Furthermore, OCs with primary checking reported lower confidence in long-term memory than did OCs without primary checking. These results suggest that when OCs are repeatedly exposed to threat-related stimuli (such as repeated checking), their level of confidence in remembering these stimuli paradoxically decreases.

Health concerns in patients with obsessive-compulsive disorder.

In the present study, individuals with obsessive-compulsive disorder (OCD) who also had excessive health concerns (n = 56) were compared with OCD individuals without such concerns (n = 343) regarding their OCD symptom severity, types of obsessions and compulsions, insight into the irrationality of their obsessions, and prevalence of generalized anxiety disorder. While the presence of health concerns did not affect the severity of OCD symptoms, the groups differed with respect to the types of symptoms displayed: those with health concerns had more somatic and harm obsessions, and checking compulsions: whereas those without such concerns had more contamination obsessions and washing compulsions. The insight of both groups ranged from poor to excellent, yet the number of individuals with poor insight was greater among those with health concerns than those without. Generalized anxiety disorder was also more prevalent among OCD individuals with excessive health concerns.

Interpersonal friction and PTSD in female victims of sexual and nonsexual assault.

This study examines the relationship among features of social relationships, both negative and positive, and later posttrauma pathology. Using a prospective design, 142 female victims of sexual or nonsexual assault were assessed at both 2 weeks and 3 months following the assault. We examined self-reported perceptions of how often the participant has been the recipient of socially supportive actions by others and how often the participant has been engaged in interpersonal friction with others. Degree of interpersonal friction shortly after the assault predicted PTSD severity 3 months later. On the contrary, positive social support did not predict later PTSD severity. These results are consistent with previous studies that underscore the association between negative features of social relationships and PTSD.