Purpose: Brain imaging: To investigate whether regular ecstasy use is associated with changes in brain n-acetylaspartate (NA), considered a marker of neuronal injury, as measured through MRS, and to measure other indicators of neuronal health (such as myoinositol and choline). Specific hypothesis tested - that ecstasy users would have lower NA/Cr and NA/Cho ratios in gray matter, but not in white matter.

Design: Non-experimental (retrospective) 2-group between-group design, with drug use (ecstasy use versus no reported ecstasy use) as a between-group variable, and with all participants receiving MRS scans.

Subjects: 15 male ecstasy users and 12 male non-ecstasy users residing in the Amsterdam (Netherlands) area and recruited via flyers distributed at venues associated with the rave/dance event scene. Matching - Groups matched on gender, age and perhaps on estimated verbal IQ (data not presented).

Criteria for Inclusion - Ecstasy Users - Self-reported lifetime use of at least 50 ecstasy tablets. Non-User Controls - No self-reported lifetime use of ecstasy, though use of other drugs was permitted. All Groups - Male, healthy, as apparently indicated through medical examination and no past or current psychiatric illness, between the ages of 18 and 45 years old, and abstinent from all psychoactive drugs for 1 wk before study day, with abstinence verified through urinary drug screen.

Drug Use Parameters - Ecstasy users reported taking 723 tablets over a lifetime (range = 55-2176), with reported average dose per use of 2.1 tablets (range = 1.5-3.5). No information is provided concerning frequency of use. Reported duration of use, in months, was 67.2 months (range = 30-144 months). Time since last use, in days, was reported at 84 days (range = 7-280 days). Other Drugs - Alcohol (reported in units per week) - Ecstasy users reported drinking 17.5 +/- 13.8 units per wk, and non-users reported drinking 13.4 +/- 11.9 units per wk. Tobacco (reported as cigarettes per day) - Ecstasy users reported smoking 13.3 +/- 14.9 cigarettes a day, and non-users reported smoking 10.8 +/- 3.7 cigarettes per day. Cannabis (number of joints in last 3 months) - Ecstasy users reported smoking 158.3 +/- 178.9 joints, and non-users reported smoking 2.3 +/- 0.5 joints in 3 months. Amphetamines (number of uses in last 3 mo) - Ecstasy users reported using amphetamine 5 +/- 8.7 times, and non-users did not report any use of amphetamines in past 3 months. Ecstasy users used significantly more cannabis and amphetamines than non-users.

Group Demographics and Matched Variables - The authors matched groups on gender, age and estimated verbal IQ. Gender, as M/F ratio - Ecstasy users = 15/0; Non-users = 12/0. Age - Average 27.2 +/- 5.3 years, and the average age of non-users was 27 +/- 4.1 years. Education - Information not provided on participants' educational attainment. Estimated verbal IQ was assessed but not reported. An earlier paper suing the same method and possibly a sub-set of participants studied in this paper reported less educational attainment in ecstasy users than in controls (Reneman et al. 2001x).

Measures: Imaging - [1H]-MRS performed with a 1.5 T MRI scanner. Regions selected for examination were mid-frontal gray matter, mid-occipital gray matter, and right parietal white matter. Ratios of brain concentrations of the following substances were measured in each area through an automatic computerized program; NA/creatine, NA/choline, myoinositol (MI)/creatine and MI/choline.

Analyses: MRS Imaging - A multivariate analysis of variance (MANOVA) was performed on all metabolite ratios, and multiple comparisons and correlations between brain regions were taken into account. Drug use (ecstasy user versus non-user) served as a between-group variable. Gray and white matter were analyzed separately. Age and extent of previous cannabis and amphetamine use served as covariates. A 1-way analysis of variance (ANOVA) was used to examine any significant differences found in the MANOVA. P was set at 0.05 for these analyses.

MRS Imaging - No Amphetamine users - After excluding 4 ecstasy users who reported intentional use of amphetamine, analyses described above were performed again.

Drug Use Parameters and MRS Imaging - Possible associations between duration of ecstasy user and time since last use were examined using Spearman's rank correlation coefficient.

Results-Significant Differences: MRS Imaging - Ecstasy users had significantly lower NA/Cr ratios in mid-frontal gray matter than non-users. Ecstasy users had significantly lower NA/Cho ratios than non-users. Age, cannabis use and amphetamine use failed to explain any variance in NA/Cr or NA/Cho ratios in mid-frontal gray matter.

MRS - No amphetamine users - NA/Cr ratios and NA/Cho rations in mid-frontal gray matter remained significantly lower in ecstasy users versus non-users after all amphetamine users were excluded from the sample of ecstasy users.

Drug Use Parameters and MRS Imaging - A significant negative correlation was found to exist between log transformed extent of ecstasy use (number of tablets taken) and NA/Cr ratios and NA/Cho ratios in mid-frontal gray matter. A greater number of reported lifetime exposures was related to lower NA/Cr and NA/Cho ratios.

Results-No Significant Differences Found: MRS Imaging - There were no significant differences between ecstasy users and non-users for NA/Cr ratios in mid-occipital gray matter or in parietal white matter. There were no significant differences between ecstasy users and non-users in NA/Cho ratios in mid-occipital gray matter or parietal white matter. Ecstasy users and non-users did not have significantly different Mi/Cr ratios in any brain region examined. Age and extent of cannabis use or amphetamine use did not influence the significant differences.

MRS Imaging - No amphetamine users - NA/Cr ratios and NA/Cho ratios in mid-occipital gray matter and parietal white matter did not differ between ecstasy users and non-users after excluding amphetamine users. There were still no differences between MI/Cr ratios in any of the 3 brain regions studied after excluding all amphetamine users.

Drug Use Parameters and MRS Imaging - There was neither a positive nor a negative association between NA/Cr or NA/Cho ratios in mid-frontal gray matter and time since last use. There were no relationships between either extent of use (log-transformed) or time since last use and NA/Cr or NA/Cho ratios in mid-occipital gray matter or parietal white matter (may not have been assessed).

Overall Effects: NA/Cr and NA/Cho ratios were lower in mid-frontal gray matter, but not mid-occipital gray matter, in a sample of male ecstasy users than in a gender and age-matched sample of non-users. The two groups had similar metabolite ratios in parietal white matter, and ecstasy users did not have higher or lower MI/Cr ratios in mid-frontal or mid-occipital gray matter, or in parietal white matter. Age and extent of cannabis use did not explain variance in NA/Cr or NA/Cho ratios in mid-frontal gray matter, and the differences in NA/Cr and NA/Cho ratios remained even after amphetamine users were excluded from analysis. A negative association was found between number of ecstasy tablets taken in a lifetime and NA/Cr and NA/Cho ratios in mid-frontal gray matter, but no relationship was found between time since last use and these ratios. The authors' hypothesis was partially confirmed. As predicted, ecstasy users and non-users did not have significantly different metabolite ratios in parietal white matter. However, while ecstasy users had NA/Cr and NA/Cho ratios in mid-frontal gray matter that were lower than values in non-users, they did not have lower NA ratios in mid-occipital gray matter.

Comments: The same team previously published a paper using MRS imaging, and some of the participants in earlier paper may also appear in this study. However, the papers did not examine the same brain areas, and the previous paper was attempting to relate NA ratios to cognitive function. Findings in this paper seem to contradict findings reported in two studies (Chang et al. 1999; Obergreisser et al. 2001). Chang and colleagues failed to find any differences between NA ratios in ecstasy users and those in non-users, but instead found that ecstasy users had elevated MI in relation to non-user controls. Using a very small sample size, Obergreisser and colleagues also failed to find any decrease in hippocampal NA in ecstasy users, as compared with non-users. The authors of this paper hypothesize that because the participants in Chang et al. were older and because they took less ecstasy overall, they may not have exhibited lower NA ratios. It should also be mentioned that Chang and colleagues examined both male and female participants, whereas this study is restricted to male participants. This study is still a retrospective study, and it is possible that self-reported use of drugs is inaccurate.