Is ecstasy addictive? A lot of casual users will tell you it isn't. As with marijuana, there's a popular conception out there that ecstasy is a "safe" drug that does not cause the kind of addiction that meth, cocaine or heroin does.
Also known as MDMA or molly, ecstasy is perhaps the most popular recreational party drug and is strongly connected with rave parties and the EDM (electronic dance music) scene. When used at these parties, it brings on feelings of empathy and euphoria along with increased sociability, all of which tends to reinforce the idea in people's minds that it is a "good" drug and is safe to take casually.
So can you get addicted to molly? Many members of the EDM scene will tell you it's not addictive, but medical science and ecstasy statistics both disagree. There are two aspects to consider here: can MDMA itself be addictive, and is what you are taking pure MDMA?
First, let's assume that what you are taking is actually MDMA, and look at that element in isolation.
MDMA is a type of amphetamine. As with other amphetamine drugs, MDMA functions by altering the normal performance of the brain's neurotransmitters. The "feel good" chemicals like dopamine and serotonin are produced in abnormally large quantities and then made to circulate for longer than they are supposed to.
Any drug that functions in this way has the potential to cause addiction, and amphetamines are always high-risk in any form. Physical dependency develops as the neurotransmitters gradually cease to function normally thanks to the presence of the drug. Though ecstasy statistics tend to show lower rates of addiction and admissions for treatment than most other types of illegal drugs, some factors are confounding the issue and making ecstasy seem safer than it actually is.
Patterns of use probably contribute heavily to ecstasy statistics; if users only take MDMA at the occasional rave and never outside of it, there is a relatively low chance of an addiction forming. If they decide to take it on a regular basis, however, they are going to be at much greater risk.
The other issue is that ecstasy is expensive, at least if it is true MDMA and not cut with cheaper ingredients. A pill that contains actual MDMA usually goes for at least $20, and dealers at parties have been known to ask for anywhere up to $100 a dose. Unlike the other addictive drugs that top the charts, such as heroin and meth, molly is neither cheap nor easily obtained.
That last point about cost is important because it means there's a huge profit incentive for drug dealers to cut MDMA with similar substances that produce similar sensations but are much more dangerous. The cheap and easy go-to in this situation is meth, of course.
Part of the reason ecstasy is so expensive is that MDMA is made from sassafras oil (safrole), which comes from the roots of a type of tree that is relatively rare. Synthesizing it accurately is difficult and nearly as expensive. So cartels simply aren't able to flood the market with pure MDMA as they are able to do with heroin and meth. What they can do, however, is cut it with all sorts of other substances. In addition to meth, DEA seizures also commonly turn up pills that are cut with bath salts, opioids and even powdered caffeine!
Ecstasy should be regarded the same way other amphetamines are. If it is used frequently or in large doses, there is significant potential for addiction.