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Background Ketamine abuse causes cognitive impairments, which negatively impact on users’ abstinence, prognosis, and quality of life. Results of cognitive impairments in chronic ketamine users have been inconsistent across studies, possibly due to the small sample sizes and the confounding effects of concomitant use of other illicit drugs. This study investigated the cognitive impairment and its related factors in chronic ketamine users with a large sample size and explored the impact of another drug use on cognitive functions. Methods Cognitive functions, including working, verbal and visual memory and executive functions were assessed in ketamine users: 286 non-heavy other drug users and 279 heavy other drug users, and 261 healthy controls. Correlations between cognitive impairment and patterns of ketamine use were analysed. Results Verbal and visual memory were impaired, but working memory and executive functions were intact for all ketamine users. No significant cognitive differences were found between the two ketamine groups. Greater number of days of ketamine use in the past month was associated with worse visual memory performance in non-heavy other drug users. Higher dose of ketamine use was associated with worse short-term verbal memory in heavy other drug users. Conclusion Verbal and visual memory are impaired in chronic ketamine users. Other drug use appears to have no impact on ketamine users’ cognitive performance.

BACKGROUND: The mortality risk is high among individuals dependent on heroin, and suicide is a severe consequence of long-term heroin use. We estimated the incidence of suicide mortality and its risk factors in a large Asian cohort with heroin dependence. METHODS: A consecutive series of 2750 inpatients dependent on heroin admitted to a psychiatric center in northern Taiwan between 1990 and 2010 were retrospectively enrolled as the study cohort. These patients were linked to the Taiwan National Mortality Database to obtain each mortality event. We determined the Standardized Mortality Ratio (SMR) for each cause of death. Among the deceased, 69 deaths were due to suicide (cases); 138 controls were randomly selected using risk-set density sampling based on a nested case-control design. We collected clinical information from subjects' medical records. Multivariate conditional logistic regression was employed to explore the correlates of suicide mortality. RESULTS: The findings showed a 7.9-fold SMR for all-cause mortality among heroin users compared to the general population while the SMR for suicide mortality was 16.2. Multivariate analysis showed that suicide attempt as the reason for the index admission (adjusted risk ratio [RR]=4.29, p=0.035) and depressive syndrome anytime during life (adjusted RR=2.61, p=0.019) were associated with the risk of suicide mortality. CONCLUSIONS: Individuals dependent on heroin are more likely to die of suicide compared to the general population. We recommend that clinical psychiatric staff carefully gather information related to the identified risk factors to prevent suicide among heroin users. Language: en

Background Prolonged exposure to methamphetamine (meth) has neurotoxic effects and impairs neurocognitive functions. This study aims to ascertain whether meth users who experience persistent psychosis suffer more severe cognitive impairment than those not experiencing persistent psychosis. Methods This cross-sectional study includes 252 participants: 25 meth users without psychosis (METH − P), 50 with brief psychosis (METH + BP), and 56 with persistent psychosis (METH + PP), as well as 54 patients with schizophrenia and 67 healthy controls. The neurocognitive function and clinical psychopathology of each patient were evaluated with the Brief Assessment of Cognition in Schizophrenia (BACS) and the Brief Psychiatric Rating Scale (BPRS), respectively. Results All cognitive domains evaluated with BACS (verbal memory, working memory, motor speed, verbal fluency, attention and processing speed, executive function, and composite scores) in METH + PP patients were similar to those in the schizophrenia patients and were worse than those in METH − P, METH + BP, and the healthy control subjects. Furthermore, cognitive functioning in meth users that did not experience persistent psychosis showed no statistically significant difference compared with the healthy control subjects. Among the meth users in this study, the negative symptom scores in the BPRS correlated to cognitive performance on the BACS, with the exception of motor speed. Conclusions Meth users display heterogeneity in their psychotic symptoms and cognitive profiles. Therefore, persistent psychotic symptoms may denote a risk for cognitive decline among meth users. Further longitudinal studies should be performed in the future to clarify the causal relationship between cognitive deficits and the development of persistent psychosis.

Lofexidine is an analogue of clonidine, an agonist at the α 2 noradrenergic receptor. Reports from preliminary open studies have suggested that it may be at least as effective as clonidine in the management of opiate withdrawal, and without the same limitation of postural hypotension. We report on a randomised double-blind comparison of lofexidine versus clonidine in the treatment of heroin withdrawal. A total of 80 hospitalized heroin addicts were randomly assigned to treatment with lofexidine or clonidine during in-patient opiate withdrawal. Maximum daily doses were 1.6 mg for lofexidine and 0.6 mg for clonidine. There was marked diurnal variation of withdrawal symptoms with severity being greatest at the daytime reading at 16.00 h and being markedly less at the night-time reading (recorded at 08.00 h). Lofexidine and clonidine were equally effective in treating the withdrawal syndrome. However, significantly more problems relating to hypotension were encountered with subjects on clonidine, with twice as many instances of withholding medication due to hypotension in the clonidine group. Better treatment retention rates were seen in the lofexidine group, although no difference was found in the proportion who had reached minimal symptom severity by the time of their discharge. We conclude that lofexidine and clonidine are equally effective, but with significantly fewer hypotensive problems with lofexidine. Further benefit from lofexidine may be possible with revised dosing regimens. Outpatient studies of lofexidine are now indicated.