The profession of neuropsychologist in Canada: Findings of a national survey.

The purpose of this study was to investigate the demographic characteristics, academic training and types of professional activities of clinical neuropsychologists in Canada.282 participants completed an online-based survey.Respondents were women for the most part and had a mean age of 43 years. They typically had doctoral-level training (85%) and about one-quarter had postdoctoral training (23%). Nearly half (47%) had a lifespan practice, over one-third (37%) had an adults-only practice, and about one-sixth (16%) had an exclusively pediatric practice. Most worked full-time (79%). Respondents were almost evenly split three ways between those who worked in the public sector, those who worked in the private sector, and those who worked in both. The most common professional activities related to assessment (95%), although clinical supervision (43%) and rehabilitation (42%) were also quite frequent, whereas research (27%) and teaching (18%) were less so. The most common reason for referral was to determine a diagnosis (79%). Pediatric neuropsychologists worked primarily with individuals with neurodevelopmental disorders and neuropsychologists working with adult populations worked primarily with individuals with emotional disorders, acquired neuropsychological disorders (traumatic brain injury, stroke/vascular), and neurocognitive disorders (dementia).At time of study, Canadian neuropsychologists seemed to enjoy a fairly balanced situation: Their level of training and the ratio of neuropsychologists per population were both high. However, these varied widely across Canada. This suggests that the profession and public interest would stand to gain from seeing training standardized to some extent nationwide.

Brain serotonin synthesis in adult males characterized by physical aggression during childhood: a 21-year longitudinal study.

BACKGROUND: Adults exhibiting severe impulsive and aggressive behaviors have multiple indices of low serotonin (5-HT) neurotransmission. It remains unclear though whether low 5-HT mediates the behavior or instead reflects a pre-existing vulnerability trait. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, positron emission tomography with the tracer alpha-[(11)C]methyl-L-tryptophan ((11)C-AMT) was used to compare 5-HT synthesis capacity in two groups of adult males from a 21-year longitudinal study (mean age +/- SD: 27.1+/-0.7): individuals with a history of childhood-limited high physical aggression (C-LHPA; N = 8) and individuals with normal (low) patterns of physical aggression (LPA; N = 18). The C-LHPA males had significantly lower trapping of (11)C-AMT bilaterally in the orbitofrontal cortex and self-reported more impulsiveness. Despite this, in adulthood there were no group differences in plasma tryptophan levels, genotyping, aggression, emotional intelligence, working memory, computerized measures of impulsivity, psychosocial functioning/adjustment, and personal and family history of mood and substance abuse disorders. CONCLUSIONS/SIGNIFICANCE: These results force a re-examination of the low 5-HT hypothesis as central in the biology of violence. They suggest that low 5-HT does not mediate current behavior and should be considered a vulnerability factor for impulsive-aggressive behavior that may or may not be expressed depending on other biological factors, experience, and environmental support during development.

In vivo measurements of brain trapping of C-labelled alpha-methyl-L-tryptophan during acute changes in mood states.

BACKGROUND: Little is known about the specific contribution of serotonin (5-HT) to the neurobiology of emotion and mood in healthy people. In an exploratory study, we sought to investigate the effect of rapid and sustained changes of emotional state on the trapping of 11C-labelled alpha-methyl-L-tryptophan (11C-alphaMtrp) used as a proxy of 5-HT synthesis, using positron emission tomography (PET). METHOD: In a within-subject repeated-measure design, participants recalled autobiographical memories to self-induce sadness, happiness and a neutral emotional state during scanning to measure brain trapping of 11C-alphaMtrp. Three separate scan acquisitions, counterbalanced for order across subjects, took place at the McConnell Brain Imaging Center, Montréal. RESULTS: Whole brain analysis revealed positive and negative correlations between experienced levels of emotions and 11C-alphaMtrp trapping in the right anterior cingulate cortex. CONCLUSION: These findings point to a mechanism whereby state-related changes in a proxy of 5-HT synthesis underscore aspects of the self-regulation of normal mood.