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Background: Abnormal effort-based decision-making represents a potential mechanism underlying motivational deficits (amotivation) in psychotic disorders. Previous research identified effort allocation impairment in chronic schizophrenia and focused mostly on physical effort modality. No study has investigated cognitive effort allocation in first-episode psychosis (FEP). Method: Cognitive effort allocation was examined in 40 FEP patients and 44 demographically-matched healthy controls, using Cognitive Effort-Discounting (COGED) paradigm which quantified participants' willingness to expend cognitive effort in terms of explicit, continuous discounting of monetary rewards based on parametrically-varied cognitive demands (levels N of N-back task). Relationship between reward-discounting and amotivation was investigated. Group differences in reward-magnitude and effort-cost sensitivity, and differential associations of these sensitivity indices with amotivation were explored. Results: Patients displayed significantly greater reward-discounting than controls. In particular, such discounting was most pronounced in patients with high levels of amotivation even when N-back performance and reward base amount were taken into consideration. Moreover, patients exhibited reduced reward-benefit sensitivity and effort-cost sensitivity relative to controls, and that decreased sensitivity to reward-benefit but not effort-cost was correlated with diminished motivation. Reward-discounting and sensitivity indices were generally unrelated to other symptom dimensions, antipsychotic dose and cognitive deficits. Conclusion: This study provides the first evidence of cognitive effort-based decision-making impairment in FEP, and indicates that decreased effort expenditure is associated with amotivation. Our findings further suggest that abnormal effort allocation and amotivation might primarily be related to blunted reward valuation. Prospective research is required to clarify the utility of effort-based measures in predicting amotivation and functional outcome in FEP. [ABSTRACT FROM AUTHOR]

Hashimoto's encephalopathy may present with a variety of neurological symptoms and signs, including myoclonus, epileptic seizures, disturbance of consciousness, psychosis, ataxia, and presenile dementia. This report is of a 57-year-old woman with a history of thyroid disease who was investigated for generalised seizures, rapid decline in cognitive function, increasing dependency, and gradual change in personality. High thyroid autoantibody titres confirmed the diagnosis of Hashimoto's encephalopathy and her symptoms improved with treatment with prednisolone. The differential diagnosis of presenile dementia, aetiology and pathogenesis of Hashimoto's encephalomyelitis, and treatment options are discussed. Hashimoto's encephalomyelitis should be considered in the differential diagnosis of presenile dementia, particularly in patients with a history of thyroid disease. [ABSTRACT FROM AUTHOR]

Two women presented independently with a clinical picture of mania-like psychosis after taking over-the- counter herbal slimming pills. Subsequent toxicology investigation found sibutramine in the samples of both patients. Sibutramine is an effective pharmacological treatment for obesity with a relatively favourable side-effect profile. However, neuropsychiatric side-effects of sibutramine have emerged with increasing use of the medication. Sibutramine may be associated with the development of psychotic symptoms in susceptible individuals. Further studies should aim at establishing any causal relationship between sibutramine and psychosis. There also seems to be an emerging trend of adulteration of over-the-counter slimming products with pharmaceutical analogues in Hong Kong. Physicians should be vigilant to the possibility of non-prescribed drug use when patients present with suspicious symptoms while using herbal remedies. [ABSTRACT FROM AUTHOR]

Objective: To examine the rate of choking incidents and the associated factors among Chinese psychiatric patients in Hong Kong over a 12-year period. Methods: All choking incidents recorded in a large psychiatric unit in Hong Kong during the inclusive period January 1996 to December 2007 were retrospectively analysed with respect to demographic and clinical variables, and circumstantial factors at the time of the incident. Results: Nineteen choking incidents involving 17 patients were identified. In psychiatric inpatients, the mortality rate due to choking was 8-fold higher than that of the general population. Different age-groups exhibited different clinical characteristics related to the incidents. Medication side-effects and poor eating habits were implicated as contributory causes. Conclusion: Mental health professionals should have a high awareness of the increased risk from choking in psychiatric patients, identify those at high risk, and implement effective preventive measures. [ABSTRACT FROM AUTHOR]