Biomedical subjects

Philip N Murphy

Publications and source records attributed to Philip N Murphy.

7 recordsLinked to original sources

PubMed2006

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

The research evidence regarding the potential effects of ecstasy suggests that it may be neurotoxic and that its use is associated with cognitive impairment. In recent years evidence has emerged suggesting that cannabinoids, the active ingredients in cannabis, can be neuroprotective under certain conditions. Given that many ecstasy users also consume cannabis at the same time, the possibility emerges that these individuals might be less susceptible to ecstasy-related impairment. The present paper reanalyses the data from a number of previous studies, contrasting the performance of those individuals who generally consume cannabis and ecstasy at the same time with those who generally consume ecstasy on its own. The two ecstasy-using groups are compared with non-ecstasy users on a range of measures including processing speed, random letter generation, verbal and visuo-spatial working memory span, reasoning and associative learning. The two ecstasy user groups did not differ significantly from each other on any of the measures. Both user groups were significantly worse than non-ecstasy users on measures of associative learning, verbal and visuo-spatial working memory and reasoning. The results suggest that consuming cannabis at the same time as ecstasy does not reduce the likelihood of cognitive impairment.

Age Factors↗

PubMed2006

Users' perceptions of the risks and effects of taking ecstasy (MDMA): a questionnaire study.

This self-report questionnaire study examined ecstasy users' perceptions of the risks associated with their use of ecstasy, their precautions against such risks, and its perceived effects on their lives. Gender differences in these areas were also explored. The sample comprised 328 ecstasy users (139 female, 187 male, one transsexual) with a mean age of 22.5 years (SD = 4.9 years). Questionnaires were completed either in hard copy or through a website concerned with ecstasy use. The results showed that friends were the most common source of information about ecstasy for the sample overall, although females were more likely to utilize this source than males. None of the five categories of perceived risk (e.g. psychiatric, physical) showed a significant gender difference. Males were more likely to take rest breaks whilst females were more likely to limit consumption as a precaution against harm. Three factors emerged from a principal components analysis concerning perceived personal change since initiation of ecstasy use. Factor 1 (23.8% of the variance) concerned negative experiences (e.g. depression). Factor 2 (22.0% of the variance) concerned positive personal qualities (e.g. caring). Factor 3 (10.5% of the variance) concerned selective aspects of functioning (e.g. alertness). The pattern of Factor 1 and Factor 2 scores over time suggested that 6 years since initiation of ecstasy use might be a time when some long-term users may be open to reassess their use of the drug. Broader implications of the findings for health education initiatives aimed at ecstasy users are discussed.

Adolescent↗

PubMed2005

Reasoning deficits in ecstasy (MDMA) polydrug users.

RATIONALE/OBJECTIVES: Previous research has shown that ecstasy users are impaired in thinking and reasoning. The present study sought to explore the possibility that syllogistic reasoning errors in ecstasy users were due to an inability to construct a model of the premises due to working memory limitations. METHODS: Twenty-nine ecstasy users and 25 nonecstasy user controls completed abstract syllogistic reasoning problems varying in difficulty. Pairs of premises were provided, and participants were required to generate conclusions that followed necessarily from them. RESULTS: On the easier problems, both groups performed at well above chance although nonusers achieved significantly more correct responses. Consistent with existing research, on the more difficult problems, errors by nonusers were characterised by incorrect conclusions suggesting that while nonusers have the working memory capacity to construct a single model of the premises, this is not an exhaustive representation and usually results in an erroneous conclusion. On the other hand, for all problem types, ecstasy users, rather than produce incorrect responses, were more likely to fail to generate a conclusion. CONCLUSIONS: The present results are consistent with the possibility that ecstasy users with their reduced working memory capacity may experience difficulty in constructing even a single model of the premises. While this might be attributable to the effects of 3,4-methlylenedioxymethamphetamine neurotoxicity, many of the ecstasy users in the present study were polydrug users. Thus, the possibility that other drugs including cannabis and cocaine might contribute to the present results cannot be excluded.

Adult↗

PubMed2005

Does alexithymia differentiate between patients with nonepileptic seizures, patients with epilepsy, and nonpatient controls?

Considering the evidence of an association between alexithymia and somatization, this study aimed to discover whether alexithymia could distinguish patients with psychogenic nonepileptic seizures (NES) from those with epilepsy (ES) and nonpatient controls (C). Toronto Alexithymia Scale (TAS-20) scores were obtained from 21 matched participants from each of these groups, together with measures of anxiety and depression. Overall TAS-20 scores did not differentiate the three groups after controlling for anxiety and depression, but scores on certain subscales of the TAS-20 differed significantly between the patient groups and the controls. Although alexithymia could not discriminate individuals with NES from those with organic manifestations, whether the etiology of alexithymia may differ according to patient group was discussed. Given that 90.5% of NES patients were identified as alexithymic, treatment approaches used for individuals with alexithymia may be usefully applied to those with NES.

Adolescent↗

PubMed2005

Syllogistic reasoning performance in MDMA (Ecstasy) users.

Previous research has demonstrated working memory and executive deficits in recreational users of MDMA (3,4-methylenedioxymethamphetamine; Ecstasy). In turn, both of these constructs have been implicated in syllogistic reasoning performance. Twenty-two MDMA users (mean age = 21.36) and 26 MDMA nonuser controls (mean age = 21.31) were tested on syllogisms of varying difficulty and on measures of working memory and executive functioning. MDMA users were significantly impaired in aspects of syllogistic reasoning, and the effect remained significant after the authors controlled for the use of other drugs. However, the MDMA-related variance was reduced to below statistical significance following control for group differences in working memory span. The results are consistent with the possibility that MDMA-related deficits in aspects of executive functioning result in impaired reasoning performance among MDMA users.

Adolescent↗

PubMed2004

Visuospatial memory impairments in users of MDMA ('ecstasy').

RATIONALE: Previous studies have presented conflicting findings regarding visuospatial span deficits in MDMA ('ecstasy') users, possibly attributable to a lack of distinction between simple visuospatial span and visuospatial working memory span. Both draw upon central executive processing, while the latter also involves concurrent goal-orientated visuospatial processing. OBJECTIVES: This study compared visuospatial working memory span for MDMA users and controls. An additional concurrent task also loading on the central executive tested for inter-group differences related to central executive workload. METHOD: MDMA user group (25 current users, 10 previous users and 18 non-users) was between-participants, and dual task condition (concurrent alphabetic generation, random letter generation, and no dual task) was within-participants. The visuospatial working memory task required participants to serially recall a spatial sequence while simultaneously completing a visual judgement task, and was completed on its own and under dual task conditions. RESULTS: Overall, non-users performed significantly better than both MDMA user groups. However, contrary to expectation, the performance decrement among users was no worse with concurrent random generation than under control conditions. Analyses controlling for background variables and the use of other drugs in the previous 3 months showed that the main effect of MDMA remained significant following control for intelligence, alcohol, amphetamines and cocaine, among other potential confounds. Unclear results were found following control for cannabis use. CONCLUSIONS: The MDMA users experienced deficits in visuospatial working memory span. The lack of interaction between dual task condition and user group may be due to inter-group differences in central executive utilisation under different task conditions.

Adult↗

PubMed2003

Predicting postdischarge opiate abstinence from admission measures of motivation and confidence.

Admission scores from a model comprising 3 motivation factors concerning the cessation of heroin use and a confidence scale concerning postdischarge abstinence were tested for their ability to predict postdischarge outcomes in patients beginning inpatient opiate detoxification. Statistically significant prediction of abstinence from heroin 30 days after discharge and the number of heroin-free days in the 3 months following admission was based on the confidence scale and a factor concerned with externally imposed constraints on continued heroin use. The single-scale confidence measure made the largest contribution to each prediction, indicating that such scales may be potentially useful outcome predictors for postdischarge abstinence. External constraints on heroin use may not provide a basis for success in this treatment modality.

Adult↗