Although long-term use is less likely to produce a physical dependence than many other drugs, such as alcohol and heroin, recent research has shown that some users of cannabis may experience a mild withdrawal when they try to stop using the drug. Users may experience sleep disturbance, anxiety, irritability and stomach cramps. It is estimated that roughly 1 in 10 cannabis users will experience some problem with their use. Long-term ecstasy users often talk about the drug being much less potent today than it was in the past. This may be related to the strength of the drug but is also affected by tolerance.
Tolerance occurs when a person needs higher doses of a drug to achieve the same effects.
Research indicates that users do develop tolerance, often attempting to recapture the feelings of their first ecstasy tablet by taking higher doses. Taking more ecstasy may not increase the perceived positive effects but does increase the potential harms. Since 1995, police seizures have rarely identified tablets that contained even 100 milligrams of the drug. Recently however, ecstasy manufacturers have been able to make tablets that have far more MDMA than we have had for many years. For long-term ecstasy users it may appear that their prayers have been answered, but in reality this could cause real problems if certain harm reduction strategies are not followed.