Purpose: Neuropsychological, to investigate the occurrence of psychiatric problems and complaints in recreational drug users and to determine the roles played by ecstasy versus drug use in general in relation to these complaints.

Design: Retrospective (non-experimental) 6 (drug use) x 4 (city) design, with drug use (non-drug use, alcohol/tobacco, cannabis, polydrug-no ecstasy, polydrug-light ecstasy and polydrug-heavy ecstasy) serving as one (chief) between subjects factor and city (Rome, Padova, Manchester and London) serving as the other between-subjects factor. All participants completed a measure of psychiatric symptoms.

Subjects: 150 non-drug users, 185 alcohol-tobacco users, 97 cannabis users, 102 polydrug-no ecstasy users, 115 light ecstasy users, and 119 heavy ecstasy users residing in Rome and Padova (Italy), and Manchester and London (England). Participants in all groups recruited by approaching individuals in places where young people congregate (clubs, cafes, city squares, college campuses). Matching - No explicit attempts to match made, but all substance-using groups appear to be matched for age.

Criteria for Inclusion - Non-drug users - Never having used tobacco or any illicit drug, and drinking no more than 1 unit alcohol per week. Alcohol/tobacco - Never having used any illicit drug, use of tobacco permitted, but not required, and drinking more than 1 unit of alcohol per week. Cannabis users - Having used cannabis, but no other illicit drugs; use of alcohol and tobacco permitted but not required. Polydrug - no ecstasy users - Had not used ecstasy, but had used an illicit drug other than cannabis, use of cannabis, alcohol and tobacco permitted but not required. Light ecstasy users - Had taken ecstasy on 1 to 20 occasions; use of all other substances permitted but not required. Heavy ecstasy users - Had taken ecstasy on more than 20 occasions, with use of all other substances permitted but not required.

Drug Use Parameters - Ecstasy Use - Light ecstasy users had taken ecstasy on 1 to 20 occasions in a lifetime (average dose not listed). No information is provided about average dose per use, average frequency of use or average duration of use or time since last use. Heavy ecstasy users had taken ecstasy on 20 or more occasions across a lifetime (no average provided). No information is provided on average dose per use, frequency of use, duration of use or time since last use. Other drugs - Alcohol, units per wk, non-drug users, =, alcohol/tobacco, 11 +/- 14.7 (89% responded or used), cannabis users = 20.5 +/- 28.3 (80%), polydrug-no ecstasy = 21 +/- 28.5 (78%), light ecstasy = 24.2 +/- 32.6 (84%), heavy ecstasy = 29.1 +/- 42.6 (77%). Tobacco, cigarettes per wk, non-drug users = 0, alcohol/tobacco, 26.9 +/- 51.5 (37%), cannabis users = 66.4 +/- 69.6 (98%), polydrug-no ecstasy = 80,9 +/- 69.4 (77%), light ecstasy users = 67.2 +/- 63.3 (73%), heavy ecstasy users = 66.5 +/- 79.4 (66%). Cannabis, average of 4-point scale, 0 = non-user, 3 = heavy, non-drug users, 0, alcohol/tobacco = 0, cannabis users = 2.6 +/- 0.5 (100%), polydrug-no ecstasy - 2.7 +/- 0.4 (84%), light ecstasy = 2.8 +/- 0.4 (84%), heavy ecstasy users = 2.9 +/- 0.3 (91%). Amphetamines, lifetime use (estimated lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 10.9 +/- 35.7 (48%), light ecstasy users = 17.6 +/- 56.5 (64%), heavy ecstasy users = 124.1 +/- 233.8 (83%). Cocaine, (estimated) lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 21.4 +/- 77.5 (54%), light ecstasy users = 23.5 +/- 99.3 (72%), heavy ecstasy users = 78 +/- 158.8 (80%). LSD, lifetime use (estimated), occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 7.5 +/- 50.1 (34%), light ecstasy users = 5.9 +/- 14.6 (51%), heavy ecstasy users = 72.6 +/- 234.5 (81%). Magic mushrooms, (estimated) lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 2.4 +/- 7.3 (28%), light ecstasy users = 2.5+/- 9.9 (39%), heavy ecstasy users = 11.5 +/- 51.1 (54%). Barbiturate/benzodiazepine, (estimated) lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 47.7 +/- 229 (14%), light ecstasy users = 73.1 +/- 445.4 (17%), heavy ecstasy users = 43 +/- 256.7 (27%). Opiates, estimated lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 261.2 +/- 993.5 (18%), light ecstasy users = 102.7 +/- 609.5 (24%), heavy ecstasy users = 108.5 +/- 565.6 (27%). Anabolic steroids, estimated lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 0.6 +/- 4.5 (4%), light ecstasy users = 4 +/- 19.3 (5%), heavy ecstasy users = 4.4 +/- 33.3 (3%). Solvents, estimated lifetime use, occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 6.7 +/- 51 (16%), light ecstasy users = 1.8 +/- 9.9 (17%), heavy ecstasy users = 6.4 +/- 28.4 (18%). Poppers, estimated lifetime use , occasions, non-drug users, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 9.6 +/- 51.8 (38%), light ecstasy users = 5.7 +/- 17.8 (36%), heavy ecstasy users = 17.5 +/- 44.8 (42%). Ketamine, estimated lifetime dose, non-drug, alcohol/tobacco and cannabis users = 0, polydrug-no ecstasy = 0.01 +/- 0 (1%), light ecstasy users = 0.1 +/- 0 (4%), heavy ecstasy users = 1.8 +/- 5.8 (24%).

Group Demographics and Matched Variables - Authors apparently did not match participants on any one variable; however, age range for all substance-using groups is similar, with non-drug sample being younger. Gender - As M/F ratio (data presented as percentages): Non drug users = 60/89, 1 undeclared (40%/59%, 1%) alcohol/tobacco = 100/83, 2 (54%/45%, 1%), cannabis users = 56/39, 2 (58%/40%, 2%), polydrug-no ecstasy = 71/29, 2 (70%/28%, 2%), light ecstasy = 68/45, 2 (59%/39%, 2%), heavy ecstasy users = 96/21, 2 (80%/18%, 2%). Age - Average age for each group follows: Non-drug users = 18.8 +/- 4.8, alcohol/tobacco = 21.5 +/- 4.4, cannabis users = 21.7 +/- 4.3, polydrug-no ecstasy = 22.7 +/- 4.6, light ecstasy = 22.7 +/- 4.6, heavy ecstasy = 23.6 +/- 4.2 years. Education - No information provided on extent of education within any participant groups.

Measures: Drug Usage Patterns - Measured via UEL Drug Usage Questionnaire. Participants indicate (through marking "yes" or "no") if they have ever used each drug contained on measure, and give estimates for weekly use of alcohol, tobacco and cannabis, and estimates for lifetime consumption for a list of drugs (including ecstasy/MDMA).

Psychiatric Symptoms/Complaints - Psychiatric complaints and other somatic symptoms (sleep problems, eating problems) assessed through the SCL-90, a self-report measure used to detect psychiatric symptoms. An additional 30 items were added to address positive life events or positive moods.

Analyses: People categorized into six drug-use groups on the basis of UEL Drug Usage Questionnaire responses. A one-way ANOVA was performed on SCL-90 scores, with drug usage group (no drugs, alcohol/tobacco, cannabis, polydrug-no ecstasy, light ecstasy or heavy ecstasy) serving as the main between-groups factor, with p apparently set at 0.05. City or country was not considered a between-subjects factor, so all data collapsed across geographical location. A monotonic polynomial contrast was also performed on SCL-90 scores, with groups ordered according to increasing drug use, to test whether SCL-90 scores change in a linear fashion with increasing drug use, with p. value set at p = 0.01.

Results - Significant Differences Found: There were significant differences across drug-use groups for the following variables; somatosization, obsessive-compulsive behavior, anxiety, anger-hostility, phobic anxiety, psychoticism, MDMA side effect scales and total negative effect scales. There is a monotonic (linear) effect for all the above-mentioned SCL-90 scores, and also negative psychobiology, with greater extent of drug use and wider variety of drug use related to higher symptoms. Positive mood scores declined as drug use increased.

Results - No Significant Differences: There were no differences across groups for the following SCL-90 scales; sensitivity, depression, paranoid ideation or negative psychobiology. There were no linear relationships between drug usage and sensitivity, depression or paranoid ideation. There were no significant across-group differences for any of the positive life event/mood scales (sociability, positive moods, positive psychobiology, positive life experience, or total positive scores. There were no linear relationships between any positive life event / mood scale score and drug use except for positive mood, where a negative association was found between positive mood and extent of drug use, with lower positive mood scores associated with greater overall drug use.

Overall Effects: In a sample of mostly young people recruited in 4 cities in two nations, increasing drug use was positively associated with an increase in self-reported psychiatric and somatic symptoms, particularly those relating to anxiety or anger, rather than those relating to depression. On the other hand, there was no association between self-reported positive moods or life events and extent of drug use or types of drugs used. Rather, there was a negative association between extent of drug use and self-reported positive mood. While the authors did not perform any contrasts to investigate the use of ecstasy versus other drugs, there were no striking differences between light ecstasy users and polydrug users who did not use ecstasy. The major division appears to be between low drug use (non-drug use, alcohol/tobacco, cannabis) versus higher drug use (polydrug-no ecstasy, light ecstasy, heavy ecstasy), and not between ecstasy use versus use of other drugs.

Comments: This study is one of several seeking to determine the relationship between psychiatric symptoms and ecstasy use. The sample sizes featured in this study are quite large, increasing the statistical power of the study. In addition, the authors attempted to separate out cannabis use, polydrug use and ecstasy use by creating 6 different groups of individuals on the basis of responses to a drug usage survey. The statistical procedures used by the authors seem insufficient for distinguishing the effects of ecstasy use from the effects of polydrug use, as the authors did not seem to perform contrasts or post-hoc tests distinguishing across groups. The monotonic relationship would seem to indicate that light ecstasy users had higher symptom scores than polydrug users who did not take ecstasy, but since polydrug users reported more symptoms than individuals using cannabis alone, it would appear that polydrug use, not ecstasy use, is more strongly connected to self-reported psychiatric symptoms. As with most retrospective studies, it is difficult to rule out the effects of an unmeasured variable or reverse causation (as when psychiatric symptoms increase drug use), and others (Cole et al. in press) are concerned with the reliability of the scales employed.