MDMA Addiction and other Mental Health Issues
The use of psychoactive drugs, by definition, alters your brain chemistry. Whether it’s caffeine or heroin, there’s a short-term impact and some lingering consequences. Usually these effects are benign and short-lived, but in some cases rather dramatic and at least somewhat persistent negative effects are produced. Although research in the area is not extensive enough to objectively prove it, based on numerous anecdotal reports and the demonstrated short-term disruptions to the serotonin system caused by MDMA there is no real doubt that frequent use can and will aggravate many pre-existing psychiatric symptoms and may produce entirely new problems.
Overview: Psychological health of users
In terms of average personality and mental health, ‘ecstasy’ users are distinctively different from non-drug users. In particular, ‘ecstasy’ users have a higher rate of mental illness than both non-drug users and users of other prohibitted drugs:
Although most ‘ecstasy’ users had some form of mental illness during the four-year study, in the vast majority of cases the problem emerged before they began using ‘ecstasy’.[1]
There are also distinct differences in average mental health in both current and former heavy (about 300-400 tablets lifetime) ‘ecstasy’ users:
Compared to both non-drug users and users of other drugs, the heavy ‘ecstasy’ users were less emotionally healthy. The former users showed a trend toward less severe symptoms, but still scored almost as high on the depression and anxiety tests.[2] The traditional view has been that these problems were caused by neurotoxicity, with users never fully recovering (hence the only modest improvement.) However, in light of the evidence that even this level of use does not reliably produce detectible damage to user’s serotonin systems, it seems likely that these results primarily reflect psychiatric problems with more traditional origins (emotional traumas, environmental stresses, etc.)
Studies have also reported differences in the average personalities of ‘ecstasy’ users relative to non-users. In one study, ‘users’ scored significantly higher on a scale of novelty seeking (desire for/willingness to try new things), were more obsessive, more hostile, more psychotic and more likely to suffer sleep disturbances. ‘Ecstasy’ users categorized as “abusers” were also less harm-avoidant than non-users, but “experimental” users were not.[3] At least some of these differences are no doubt due to drug use, but to what extent can only be guessed at.
Anxiety/Panic Attacks
Panic attacks brought on by MDMA’s effects occur with some frequency. Usually, such reactions appear to occur during the onset or peak of drug effects, and may be triggered by the user’s discomfort with the drug’s effects or by a threatening/disturbing environment. User reaction can be severe; in some cases the user may believe they are dying. The most common outward manifestation of a panic attack appears to be withdrawal and inactivity/unresponsiveness. In most cases, encouraging the user to relax by assuring them that they are safe and going to be OK may be enough to help them break through the reaction. For severe cases, benzodiazepine sedatives may be useful.
Erowid reports a case of a quite severe panic attack triggered by the behavior of people around the user, who had combined ‘ecstasy’ with large amounts of marijuana:
“[After taking a pill, we stopped] to smoke another bowl or 3 and watch the moon and stars. […] As I finish, taking literally my last toke on the bowl, it suddenly hits my like a brick to the face. A great feeling similar to my first trip and bit of a body buzz, a great warm beautiful, feeling of peace and security. That euphoria and appreciation I had been searching for. It felt so good [….]
My friend N had the urge for coffee, so we stopped off at a coffee and donut shop. While N ordered, I waited sitting with J, just smiling and talking about all the great thoughts racing through my mind. J just smiled and laughed but tried to keep up in conversation with me. It’s about 10:30 or 11 at this point, I’m not quite sure, and a girl from our school shows up at the coffee shop with her friend. They come and talk to us, and the girl, K, from my sociology class, begins to talk to me, which delights me, as I’ve always wanted to talk to her, but never had the real opportunity or reason. She informs me that she’s partly drunk, which is evident even to me, but we talk about things from school and laugh, and seem to all be enjoying each other’s company. She turns to me and asks if I smoke weed, to which I reply yes, and she asks ‘are you stoned right now?’. I explain to her, that while I did get high on cannabis that evening, that was not what was affecting me. She asks what I’m on in a curious voice and whisper Ecstasy to her. This is where things go down hill, as she reacts strangely, pulling away with a mild disgust on her face. She asks if I’m serious to which i reply yes. She than freaks out, and tells her friend, in a rather loud manner, which began to make me feel strange. Her and her friend get up, and smile at us partly, but say that they can no longer talk to us, knowing that i’m on Ecstasy. I sit there confused, unable to tell if they are joking/being sarcastic, or if they are serious. They then leave our table and go to sit with another group of guys. I’m left somewhat amazed and simply weirded out. I repeatedly begin to ask my friends what just happened. They keep saying ‘that’s hardcore! Those girls just completely flipped on us man, that’s not cool’ I actually remember my friend N saying this exact sentence in a very pissed off tone, based on the treatment we just received.
I sat continuing to ask questions, that I don’t recall at the moment. What I didn’t seem to notice at the time, I suppose because I was caught up in what just occurred, is that my vision is changing on me. I don’t realize it immediately, but my vision is beginning to distort. My friends faces are becoming blurry and wavy in front of my eyes, every light and color seems almost to bright to look at, and I notice myself having difficulty seeing anything normally. My friends faces almost appear to be dripping in front of me. I also notice my stomach beginning to feel very strange, with some pain, and nausea, and a feeling of just having a very upset body. I continue trying to talk, but my friends notify me that I’m talking uncontrollably loudly, and in a robotic state, where I’m talking very slowly, with the tone of my voice going up and down. I meet difficulty stringing fluent, intelligible sentences together, and find myself having difficulty communicating properly. My hands also are moving uncontrollably slow, and I find myself getting distracted by waving them in front of my face. My friends are slightly concerned, noticing the extreme, quick change in me, and being in such a small public place with so many people around us.
I get up suddenly and go to the washroom feeling the need both to urinate and vomit. Unfortunately upon getting the washroom (after having to struggle to walk as normal as possible past a line up of people), I find that I can neither urinate nor vomit. When I attempt urination, i feel the need to go, but nothing comes out, and I am overcome with nervousness and a feeling of impending doom, dread and hopelessness. A sense of absolute fear comes over me, and I give up on urination, and hunch over, clawing at my stomach, feeling the need to vomit, but to know avail. Only disgusting sounds come out of my mouth, as I try to force it out of me. Nothing. For 15 minutes I stood in the washroom alone, hunched over, clutching my stomach, feeling absolutely afraid and unable to move or function. My body aches, and had become excessively overheated, even though I kept myself hydrated throughout the evening, even at that moment with a bottle of water in hand. In all honesty, I felt worse and more truly scared I think than I’ve ever felt in my life, truly fearing for my life. I was able to string the sentence ‘I’m going to die’ together, which i repeated to myself over and over for 10 of my 15 mins in the washroom. I stood there, feeling i was going to die, and wishing I hadn’t taken the pills. I cursed myself in my mind for being so stupid, and began to talk aloud to myself in a mixture of prayer, despair and disgust, asking God to not let me die, over and over, and shouting loudly that I couldn’t believe I was going to die in the coffee shop washroom. I felt Helpless and lost, and was overcome with emotions. I was disgusted to be going through this in the coffee shop washroom, while memories and flashbacks of my life passed in my mind. I wouldn’t say my life flashed before my eyes, but I just kept going over a review of my life, suddenly feeling that I had just screwed up somewhere, and that I ruined my life for good. I kept my gaze on the floor and then on the urinal, but was getting dizzy with each passing moment. The floor was moving and breathing beneath me, and the urinal seemed to be moving towards me. I stopped, and pulled myself away and began to look at myself in the mirror for a few moments, which was probably not a good idea in the state I was in. I remember a feeling of just hating myself, and fearing for my life and for everything around. Just feeling lost. Looking into my eyes in the mirror, I felt I was looking into my head. I felt like I was trapped in my mind, and unable to control my body at all, feeling I was about to expire very soon. It felt like some horrible thing was inside me, in my head or body of whatever just not letting me have any control. It felt like it was trying to waste my body to nothing and I felt like I was on fire, and I couldn’t bring my body temp back down. I found myself coated in sweat, but didn’t even feel able mentally to take off my sweater by myself. I was still breathing, but in a horribly fast and violent manner, as though I could not catch my breath, though I don’t know if this was later evident to my friends.
When I finally left what seemed like forever in the Restroom, I returned to my friends as quickly and composed as possible […] then i forced myself out of the coffee shop into the parking lot, while they followed me concerned. I collapsed into the grass on the side of the lot, and closed my eyes a bit, trying to block out everything, and just repeating to my friends that I thought was going to die, but then contradicting myself and saying that I only needed a few moments to lie down and get out of the dizziness. They sat in the grass with me, and just talked to me a bit, asking how I was every 2 mins. Even with my eyes closed, in the dark of night, everything was bright, and when I opened my eyes for a moment and then closed them again, I could still see the stars in the sky. We sat out there for about 20 mins, before I forced myself to get up. I was still dizzy as hell, and my friends both aided me in crossing the street. The minute we reached the other side, I began vomiting violently[….]
As we began to walk, I vomited once more, but was generally OK, though still not done the trip completely. My state of mind was still awful, and not at all positive, however, the overwhelming fear and thoughts of death were for the most part passed, as well as most of my stomach pain, and I was able to at least laugh with my friends a bit as they tried to tell jokes, or recount humorous past events to try and make me feel better. I headed back to N’s house, where I managed to get past his father(who himself was drunk) and was able to spend the night, as there was no way I could go home. I didn’t sleep for a long time, but managed to get a couple hours in, starting at about 5 till 9 am. The next day, I felt tired, and somewhat achy, but for the most part good, and clear minded.”
MDMA-induced panic attacks can in most cases probably be avoided simply by using in a calm, non threatening environment. Limiting the dosage taken, or staggering the dosage over time (such as by taking half, waiting 20-30 minutes, then taking the other half) may also help if a person is simply nervous/prone to anxiety. (One user reported having panic attacks immediately after swallowing a pill. Since there would be insufficient time for the drug to have entered their system, this appears to be a case of a purely psychological reaction to the anticipation of the drug’s effects.) There have been a few reports of panic attacks following the use of 5-HTP as a ‘pre-load’ (taken in advance of the ‘ecstasy’.) Mixing with other drugs (such as marijuana in the above case) may also increase the risk of panic attacks.
‘Hard’ Come-downs
Perhaps best described as a post-use depression, there have been a number of reports of feeling very empty and depressed immediately after coming down from the MDMA high. Occurrence seems to be more common in women, and seems to be associated with high doses/intense experiences. There isn’t an obvious trigger (some people may just be unusually vulnerable, perhaps in association with pre-existing psychiatric problems such as depression) nor is there any clear preventive measure (although supplementing with 5-HTP when you start to ‘come down’ may help.)
General ‘Hangover’
One of the functions of the serotonin system is to control anxiety and depression. As a result, it’s not unusual for users (especially heavy/frequent users) to feel emotionally ‘brittle’ in the days following use. This may manifest itself in irritability, bursts of anger, depression, etc. Problems staying focused on a task and remembering things have also been frequently reported by users. These problems are much more likely to occur with more frequent use; they are all but unheard of in first-time or very infrequent users. Fatigue is also very common the day after use, probably largely due to sleep disruptions caused by lingering stimulant effects.
Persistent impacts of use on mental health
There is a general lack of research in the area of what problems emerge during and after periods of ‘ecstasy’ use. However, patterns have emerged from user’s anecdotal accounts that suggest the existence of several distinctive medium- to long-term types of problems:
‘E-tardation’
By far the most commonly reported scenario is irritability, anxiety, and memory/concentration problems following a period of heavy/frequent use (whether in the form of a binge or simply as a regular part of the person’s lifestyle.) In severe cases users report difficulty thinking of words/speaking. Some users report depersonalization/derealization (the sensation that you aren’t really there, that your reflection in the mirror is actually somebody else, etc.) Given the complete lack of controlled observation of these users it seems presumptuous to give a firm diagnosis or speculate on their future recovery, but the clear trend of anecdotal user reports is for slow but complete or near-complete recovery over a course of weeks to months (sometimes as long as a year) once drug use has been discontinued. Given the rather strong evidence that true neurotoxicity is at best a fairly rare event even among heavy users my assumption is that this phenomenon is primarily due to neuroadaptive mechanisms. There may be some danger of such ‘overindulgence’ depression/anxiety becoming entrenched and taking on a life of it’s own. SSRIs and counseling may be beneficial.
A visitor to Dancesafe offered this rather extreme account of problems caused at least in part by heavy ‘ecstasy’ use:
“In the spring of 2002 I rolled practically every other day and then slowed down to once a weekend (multiple pills each roll) then down to every now and then with little mini-binges in between, sometimes I’d go 2 weeks w/o rolling sometimes I’d roll 2-3 times a week. Then fall of 2002 I had a hookup on purecaps so I rolled every weekend.
Anyway eventually i found myself in a situation where my mind raced constantly, I was always aggravated, my anxiety was through the roof and way too much for me to handle. instead of depression I was angry almost all the time, very quick to jump on people even those close to me. I always wished I would get depressed instead where I would want to hurt myself instead of others (sometimes when I would settle down a little bit I would realize what I was doing but couldn’t seem to get a grip on it like I didn’t have control over my own emotions). On some occasions I tried starting fights with complete strangers for the most ridiculous reasons and my attitude to my fiance, who I love more than life itself, was terrible. I would yell and complain constantly, I was never satisfied.
It was almost part of my regular schedule that on sundays (before I have to go back to work on monday) my anxiety would get so bad that I would just start pacing, trying to keep myself from throwing a tantrum like a little kid over nothing, but it would always end in me getting very light headed, dizzy, nauseous, and keeled over gasping for breath when I would try to talk it out. Eventually, my fiance got tired of this cycle and me not willing to help myself, she said she couldn’t deal with it anymore that it was tearing her up watching me do this to myself and said she was going to leave me. This was the biggest eye opener of my entire life, the second I found out I got light headed and almost fell down, it felt like I was going in and out of consciousness almost. It was too late she said she had fallen out of love with me because I’m not the person I used to be anymore, I fell into a huge depression and wanted to die. I took a knife to both wrists and cut them and watched the blood run into the sink, but the knife wasn’t sharp enough to hit the artery. Now I just have the scars. I wanted to die so bad, all of a sudden my eyes were wide open and I saw all that I had done and all the hurt that I’ve caused the person who I love the most, there’s no words to describe how I felt – lower than low.”
The user in this case reports largely recovering (and reconciling with his fiance) after prolonged abstinence from all drugs and a great deal of soul-searching.
‘Drug Trauma’
In a few rare cases, users report having had a very negative experience with ‘ecstasy’ that left them emotionally troubled (anxious, depressed) for some time (weeks to months) afterwards. There is a certain inescapable logic to these reports: MDMA experiences can deeply and persistently affect the user, which is why positive MDMA experiences appear to be so therapeutic and uplifting. However, if the experience is a negative one, the drug’s fundamental effect of engraining the experience into the user’s memory and personality is still at work, potentially causing emotional trauma instead of healing it. The rare user reports of this phenomenon suggest that recovery comes with time or, in one case, the trauma was reportedly quickly and completely reversed with a positive MDMA experience.
Psychosis
There are several cases in the literature of amphetamine psychosis (losing touch with reality) in several extremely heavy users of ‘ecstasy'[4] and in a light user with a family history of possible paranoid schizophrenia.[5] There is also one case of a young man with no prior history of ‘ecstasy’ use or mental health problems who had a psychotic break following a night of heavy drinking and ‘ecstasy’ use.[6] The latter patient was brought in after pulling people from their cars and attacking their car stereos, apparently believing himself to be taking part in an elaborate role-playing game. With treatment, the patient made a full recovery over two months.
Psychosis in association with MDMA seems quite rare, probably due to the rarity of prolonged binges (somebody staying high on MDMA for even twelve hours would be unusual, while methamphetamine users routinely go several days without sleep while binging.)
A reader asks: “Isn’t a psychedelic drug high a form of psychosis anyway?” To some extent, yes; drugs like LSD, MDMA, and even alcohol impair our ability to accurately perceive and rationally evaluate the world around us. Traditionally, researchers have even described psychedelic drugs as “psychotomimetics”; drugs that imitate psychosis. However, compared to ‘traditional’ psychosis, drug effects are more predictable and usually positive, and offer the considerable comfort of knowing that whatever altered perception of reality that comes from the drug will fade in a matter of hours; people suffering from mental illness have no easy or predictable escape, a much more frightening situation even if the perceptual disturbances are similar to those a recreational psychedelic user might actively be seeking.
MDMA Addiction
“If you place a thing in the center of your life
that lacks the power to nourish
It will eventually poison everything you are and destroy you.”
-“Liontamer” by Faithless
MDMA has a low potential for addiction, but it does happen, and when it does it can be as destructive as any of the ‘hard’ drugs. For a few hours while high, MDMA can be an antidepressant and anti-anxiety drug of almost miraculous power. If you are under severe emotional strain, MDMA can provide an escape. How compelling returning to the MDMA state will be to a given person largely depends on how rotten their lives otherwise are (a common theme to drug dependency.) To a reasonably healthy, happy person with a fulfilling life the MDMA state is often a great gift; a transcendent experience to be remembered fondly as they go on with their normal lives. To somebody suffering from depression or other emotional problems, MDMA can easily become an escape; a way to run away from reality.
But what’s so wrong about that? People have a right to try to be happy.
Sadly, the MDMA state is not sustainable. While high, your serotonin system is being powerfully strengthened by the MDMA. When the high fades, there is a price to be paid: Your brain’s supply of serotonin (and sensitivity to it) has been reduced. Not only do you lose the serotonin enhancement of the MDMA, you get dropped down to below-normal levels. It can take weeks to fully recover from this effect, and it can add up. The more frequently you use, the less time you give yourself to recover between uses, the more badly your serotonin system will be disrupted. Hangovers grow longer and more severe, simple post-use fatigue gives way to anxiety, depression, memory problems, and more. This isn’t a game you can win: You can cheat on your boyfriend, cheat on your taxes, even cheat death…but you just can’t beat your own biology (at least in this case.) People that seek frequent escape in MDMA will be ground down; the problems they sought to escape will only be made worse by frequent use.
So what happens when somebody becomes compulsive in their use?
Compulsive users seem to follow one of two possible patterns. The first (and typical) pattern is one of escalating use until the side effects and hangovers become so severe that the user reaches a crisis point. They crash, swear it off, perhaps seek psychiatric help and prescription medications instead of more MDMA to deal with their problems. It’s not a pretty process, but the dependency is self-limiting by the severity of drug side effects.
In the second (apparently very rare) pattern of abuse, the user ‘makes peace’ with MDMA, accepting severely and chronically suppressed serotonin function by propping themselves up with massive frequent doses. Under this scenario, the MDMA becomes much more like methamphetamine: Its ability to draw a strong serotonin effect from the brain has been largely lost, but it retains the ability to release dopamine in significant amounts if the dose is high enough. This too is not a very sustainable condition; the longest case I’ve heard of is about a year. The fate of such users is not well known; it is likely that they too eventually crash and seek help.
In the first case, full recovery is generally expected, although it may take months for the user’s brain to get back to normal (depending on how severe the pattern of abuse was.) Frightened users may assume that the lingering effects are the result of brain damage (neurotoxicity). There is no need to assume the worst; although their brains have clearly undergone temporary changes, it is unlikely that true structural damage has occurred.
In the second group, there isn’t enough data to even speculate. If anybody is a good candidate for neurotoxicity, it’s somebody who was taking thirty pills in a night.
Is there any treatment for MDMA addiction?
Yes! Pharmacologically, popular antidepressants like Prozac, Paxil, etc. can provide the enhancement of the serotonin system the abusing user is seeking without the severe side effects and disruption of life caused by heavy MDMA use. In mild cases, serotonin-elevating supplements like 5-HTP may be enough to suppress drug cravings. However, this sort of maintenance treatment doesn’t really address the underlying question of why they became abusers in the first place. If they were motivated by emotional problems, those issues must be addressed to prevent a return to drug abuse. Drug addiction is not a criminal problem. It isn’t a law enforcement problem. It isn’t even primarily a physical health problem (although that can be a side effect.) At its core, drug abuse is usually a matter of people with psychological issues trying to treat themselves with the tools available to them (prohibited drugs which, in spite of all government efforts, are still often easier to get than common antidepressant prescriptions.) Putting addicts in prison for their drug use is vicious and unproductive: About all you can hope to accomplish is to reduce the chances of them using drugs while behind bars.
For the sake of clarity, let me repeat that drug use (occasional, controlled) is not the same thing as drug abuse (frequent, compulsive, destructive to the user’s regular life.) The person that enjoys a few beers on a Friday night is not an alcoholic, nor is the occasional user of prohibited drugs an addict. Whether the law approves of a particular drug or not is irrelevant when the question is one of responsible vs. unhealthy patterns of use. Treating most users of prohibited drugs as addicts is not justified; the vast majority of users are not dependent, and neither want nor would benefit from treatment programs.
How addictive is MDMA compared to other drugs?
There’s not as much data to go by as I would like, but what we do have suggests that MDMA is one of the less addictive recreational drugs. In spite of MDMA being used recreationally in the US for over forty years, the first addicts weren’t documented in the literature until 1999.[7]
We also have some field research evaluating how dependent users were to different drugs. Severity of Dependence scores (a scale used to gauge how addicted a user is) have been gathered for a number of popular drugs: [8]
The “contact” group was drug users who were known to police or getting services (needle exchange programs, etc…’addicts’ in the traditional sense.) The “no contact” group was users who were not seeking or getting treatment, were not known to police, etc. Perhaps the most interesting finding is that the “ecstasy” scores for severity of dependence (addiction) were actually half those of marijuana. I only wish they had included alcohol (I expect it would score at least as highly as marijuana.) Also missing are cigarettes, which some research has suggested are similar to heroin in addictiveness.
In a large German study, ecstasy was found to have a lifetime rate of abuse (patterns of use that interfere with normal activities/obligations) of roughly one in five users, comparable to that of other psychedelics such as LSD. The same study claimed that, over the lifetime of users, about one in ten would meet the DSM-IV requirements for dependence.[9] The latter number may be somewhat inflated due to some of MDMA’s unusual characteristics, such as the common occurrence of a ‘hangover’ period that can last for several days (which might be inaccurately identified as a withdrawal symptom.)
Also of interest, animal behavioral research has found that rats in a social environment (with other rats to play with and interact with) do not find MDMA addictive, but socially isolated rats do.[10] This fits very well with anecdotal reports of human abusers; it seems likely that a major factor in the development of MDMA dependence is an underlying emotional need for a sense of connection and acceptance.
Avoiding addiction
The first step in avoiding addiction is understanding that it does happen, and can happen to you. Some people are at very little risk of addiction while others are at high risk, but anybody can become addicted under the right circumstances.
Second, be sensitive to what your mind and body are telling you. Pay attention to drug cravings; the more you want a drug, the less wise it is to give in to that urge. The worst of addiction problems always start with “well…just one more time/line/pill can’t hurt.” Drugs can be a lot of fun, so it’s understandable that people can get carried away when they discover a new one…but if you don’t control your use, it may end up controlling you.
And finally, don’t be shy about asking for help. If you feel drugs have become too big a part of your life, talk to a friend, doctor or psychologist. Sometimes just talking helps, and they can prescribe medications that can help with anxiety, depression, or other issues that may be contributing to the problem. Drug addiction happens. It’s not a sin, and doesn’t mean you were weak or are a bad person. Never be afraid to ask for help; medical professionals are there to help you, not to judge you.
[1] Lieb R, Schuetz CG, Pfister H, von Sydow K, Wittchen H “Mental disorders in ecstasy users: a prospective-longitudinal investigation.” Drug Alcohol Depend 2002; 68: 195-207. Abstract.
[2] Morgan, MJ, McFie, L, Fleetwood, LH and Robinson, JA “Ecstasy (MDMA): Are the psychological problems associated with its use reversed by prolonged abstinence?” Psychopharmacology (Berl) 2002; 159: 294-303. Abstract.
[3] Dughiero G, Schifano F, Forza G “Personality dimensions and psychopathological profiles of Ecstasy users.” Hum Psychopharmacol Clin Exp 2001 16: 635-639. Abstract.
[4] Creighton FJ, Black DL, Hyde CE “‘Ecstasy’ psychosis and flashbacks.” Br J Psychiatry, 1991; 159:713-5. Abstract.
[5] Williams H, Meagher D, Galligan P “M.D.M.A. (‘Ecstasy’); a Case of Possible Drug-Induced Psychosis.” Ir J Med Sci, 1993; 162(2):43-4. Abstract.[6] Vaiva G, Boss V, Bailly D, Thomas P, Lestavel P, Goudemand M “An ‘Accidental’ Acute Psychosis with Ecstasy Use.” Journal of Psychoactive Drugs, 2001; 33(1):95-8. Abstract.
[7] Jansen KL, “Ecstasy (MDMA) Dependence”, Drug and Alcohol Dependence, 1999;53,2:121-124. Abstract.
[8] Robson P, Bruce M “A comparison of ‘visible’ and ‘invisible’ users of amphetamine, cocaine, and heroin: two distinct populations?” Addiction, 1997;92(12):1729-1736. Abstract.
[9] Schuster P, Lieb R, Lamertz C, Wittchen HU “Is the Use of Ecstasy and Hallucinogens Increasing?” European Addiction Research 1998; 4:75-82. Abstract.
[10] Meyer A, Mayerhofer A, Kovar K, Schmidt W “Rewarding effects of the optical isomers of [MDMA] and [MDEA] measured by conditioned place preference in rats”, Neurosci Lett 2002; 330(3):280-4. Abstract