It has been hypothesized that changes in striatal-mediated dopamine modulation during adolescence may increase the risk for initiating substance abuse as a result of its fundamental role in arbitrating reward sensitivity and motivation during learning and decision making. However, substance abuse during adolescence may also significantly modify striatal structure and function and concomitantly alter reward sensitivity and action control while this brain region is undergoing remodeling. In the present investigation, to assess the relationship of methamphetamine (Meth) or Meth and cannabis (CA) abuse to regional striatal morphology, we acquired structural magnetic resonance images, using a 3T Siemens Trio scanner, from three groups of adolescents composed of healthy controls (n = 10), Meth abusers (n = 9) and combined Meth and CA abusers (Meth+CA, n = 8). We also assessed novelty seeking using the novelty seeking subscale of Cloninger's Tridimensional Character Inventory. The results indicate that adolescent Meth+CA abusers have increased regional striatal volume and show intensified novelty seeking in contrast to the controls. The degree of Meth exposure was also positively correlated with regional striatal volume and novelty seeking in both the Meth and Meth+CA users. These preliminary findings support theories that propose a role for the striatum in adolescent substance abuse and further indicate that novelty seeking may be related to the initiation of, or sustained, drug use.
Working memory is a vital cognitive capacity without which meaningful thinking and logical reasoning would be impossible. Working memory is integrally dependent upon prefrontal cortex and it has been suggested that voluntary control of working memory, enabling sustained emotion inhibition, was the crucial step in the evolution of modern humans. Consistent with this, recent fMRI studies suggest that working memory performance depends upon the capacity of prefrontal cortex to suppress bottom-up amygdala signals during emotional arousal. However fMRI is not well-suited to definitively resolve questions of causality. Moreover, the amygdala is neither structurally or functionally homogenous and fMRI studies do not resolve which amygdala sub-regions interfere with working memory. Lesion studies on the other hand can contribute unique causal evidence on aspects of brain-behaviour phenomena fMRI cannot "see". To address these questions we investigated working memory performance in three adult female subjects with bilateral basolateral amygdala calcification consequent to Urbach-Wiethe Disease and ten healthy controls. Amygdala lesion extent and functionality was determined by structural and functional MRI methods. Working memory performance was assessed using the Wechsler Adult Intelligence Scale-III digit span forward task. State and trait anxiety measures to control for possible emotional differences between patient and control groups were administered. Structural MRI showed bilateral selective basolateral amygdala damage in the three Urbach-Wiethe Disease subjects and fMRI confirmed intact functionality in the remaining amygdala sub-regions. The three Urbach-Wiethe Disease subjects showed significant working memory facilitation relative to controls. Control measures showed no group anxiety differences. Results are provisionally interpreted in terms of a 'cooperation through competition' networks model that may account for the observed paradoxical functional facilitation effect.
The recent National Mental Health Summit included discussion of research priorities for South Africa. This paper reviews some of the background literature that is relevant to this key issue. It draws attention to one contested question, the extent to which research in low and middle income countries should address questions about fundamental mechanisms and clinical treatments versus focusing on questions about implementation and systems research? In addressing this question, the paper argues that the boundary between good clinical practice and good academic scholarship is not nearly as distinct as is often assumed (the "research fallacy"); prospective rigorous assessments, retrospective clinical audits, evidence-based medicine, and useful information systems all point to the mutual interdependence of good practice and good scholarship. Finally, some general conclusions that the majority of summit delegates participating in the discussion on research agreed to, are presented.
Read moreGiven the need for more efficacious treatments in OCD, and given emergent findings on the role of the glutamatergic system in this disorder, there is a need for additional pharmacotherapy trials on glutamatergic agents in OCD. Possible research designs for such trials might include stand-alone approaches, pharmacotherapy augmentation, or psychotherapy augmentation.
Read morePanic disorder (PD) is an anxiety disorder that affects many South Africans. If undiagnosed or mismanaged, this condition may impact profoundly on an individual's functioning and quality of life. At the primary level, the assessment of panic attacks requires consideration of a number of differential diagnoses. General practitioners also play an invaluable role in the acute and long-term care and appropriate referral of individuals with PD. This article provides an overview of PD in general practice and includes a guideline for case identification and therapeutic options.
Read moreIndividuals with BD show decreased attentional readiness and activation of non-relevant information processing during attentional processes. These data are the first that show, MBCT in BD improved attentional readiness, and attenuated activation of non-relevant information processing during attentional processes.
Read moreThis guideline focuses on the pharmacotherapy of obsessive compulsive disorder(OCD). OCD is characterised by obsessions and<div style="left: 70.8662px; top: 364.72px; font-size: 15.45px; font-family: serif; transform: scaleX(0.99966);" data-canvas-width="420.56549999999993">compulsions. A number of other disorders are also characterised by</div><div style="left: 70.8662px; top: 384.72px; font-size: 15.45px; font-family: serif; transform: scaleX(0.97309);" data-canvas-width="419.07749999999993">repetitive thoughts and rituals and may also respond to modifications</div>of standard OCD treatment.
Read moreThe study provides novel evidence of increasing levels of early non-fatal suicidality recalled by younger South Africans. Levels appeared significantly higher in Whites than in Blacks. Socio-economic contexts in early life were interpreted as mediators rather than confounders of the association between race and recalled early suicidality. The findings for decreased levels of suicidality among participants growing up in lower socio-economic strata and rural settings in South Africa require further investigation. The need for widespread suicide prevention programmes targeting young people at a population level is emphasised.
Read moreThis large-scale population-based study suggests that high serum folate concentration may be associated with modestly increased prostate cancer risk. We did not observe an association between vitamin B12 status and prostate cancer risk.
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