Effects of amisulpride, risperidone and chlorpromazine on auditory and visual latent inhibition, prepulse inhibition, executive function and eye movements in healthy volunteers.

In view of the evidence that cognitive deficits in schizophrenia are critically important for long-term outcome, it is essential to establish the effects that the various antipsychotic compounds have on cognition, particularly second-generation drugs. This parallel group, placebo-controlled study aimed to compare the effects in healthy volunteers (n = 128) of acute doses of the atypical antipsychotics amisulpride (300 mg) and risperidone (3 mg) to those of chlorpromazine (100 mg) on tests thought relevant to the schizophrenic process: auditory and visual latent inhibition, prepulse inhibition of the acoustic startle response, executive function and eye movements. The drugs tested were not found to affect auditory latent inhibition, prepulse inhibition or executive functioning as measured by the Cambridge Neuropsychological Test Battery and the FAS test of verbal fluency. However, risperidone disrupted and amisulpride showed a trend to disrupt visual latent inhibition. Although amisulpride did not affect eye movements, both risperidone and chlorpromazine decreased peak saccadic velocity and increased antisaccade error rates, which, in the risperidone group, correlated with drug-induced akathisia. It was concluded that single doses of these drugs appear to have little effect on cognition, but may affect eye movement parameters in accordance with the amount of sedation and akathisia they produce. The effect risperidone had on latent inhibition is likely to relate to its serotonergic properties. Furthermore, as the trend for disrupted visual latent inhibition following amisulpride was similar in nature to that which would be expected with amphetamine, it was concluded that its behaviour in this model is consistent with its preferential presynaptic dopamine antagonistic activity in low dose and its efficacy in the negative symptoms of schizophrenia.

Executive functioning in Alzheimer's disease and vascular dementia

Objective: To compare performance of patients with mild-moderate Alzheimer's disease (AD) and vascular dementia (VaD) on tests of executive functioning and working memory.

Methods: Patients with AD (n = 76) and VaD (n = 46) were recruited from a memory clinic along with dementia free participants (n = 28). They underwent specific tests of working memory from the Cognitive Drug Research (CDR) battery and pen and paper tests of executive function including CLOX 1 & 2, EXIT25 and a test of verbal fluency (COWAT). All patients had a CT brain scan which was independently scored for white matter change/ischaemia.

Results: The AD and VaD groups were significantly impaired on all measures of working memory and executive functioning compared to the disease free group. There were no significant differences between the AD and VaD groups on any measure. Z-scores confirmed the pattern of impairment in executive functioning and working memory was largely equivalent in both patient groups. Small to moderate correlations were seen between the MMSE and the neurocognitive scores in both patient groups and the pattern of correlations was also very similar in both patient groups.

Conclusions: This study demonstrates sizeable executive functioning and working memory impairments in patients with mild-moderate AD and VaD but no significant differences between the disease groups. Copyright (C) 2009 John Wiley & Sons, Ltd.

Experiences with mephedrone pre- and post-legislative controls: Perceptions of safety and sources of supply

Background: Drug scenes within several countries have changed in recent years to incorporate a range of licit psychoactive products, collectively known as “legal highs.” Hundreds of different legal high products have been described in the literature. Many of these products contain synthetic stimulants that allegedly
“mirror” the effects of some illicit drugs. In 2009–2010, growing concern by the UK and Irish governments focused on mephedrone, a synthetic stimulant that had become embedded within several drug scenes in Britain and Ireland. In April 2010, mephedrone and related cathinone derivatives were banned under
the UK’s Misuse of Drugs Act 1971. Setting aside “worse case scenarios” that have been portrayed by UK and Irish media, little is known about mephedrone use from the consumer’s perspective. The purpose of this paper was to (1) explore respondents’ experiences with mephedrone, (2) examine users’ perceptions
about the safety of mephedrone, and primarily to (3) examine sources of mephedrone supply during the pre- and post-ban periods.
Methods: Semi-structured interviews were conducted with 23 adults who had used mephedrone during 2009–2010. Data collection occurred in May and June 2010, following the ban on mephedrone. A total of 20/23 respondents had used mephedrone during the post-ban period, and the vast majority had prior
experience with ecstasy or cocaine. Respondents’ ages ranged from 19 to 51, approximately half of the sample were female and the majority (19 of 23) were employed in full- or part-time work.
Results: Most respondents reported positive experiences with mephedrone, and for some, the substance emerged as a drug of choice. None of the respondents reported that the once-legal status of mephedrone implied that it was safe to use. Very few respondents reported purchasing mephedrone from street-based
or on-line headshops during the pre-ban period, and these decisions were guided in part by respondents’ attempts to avoid “drug user” identities. Most respondents purchased or obtained mephedrone from friends or dealers, and mephedrone was widely available during the 10-week period following the ban. Respondents reported a greater reliance on dealers and a change in mephedrone packaging following the criminalisation of mephedrone.
Conclusion: The findings are discussed in the context of what appears to be a rapidly changing mephedrone market. We discuss the possible implications of criminalising mephedrone, including the potential displacement effects and the development of an illicit market.