The results of that research indicates that light users of MDMA do exhibit mild cognitive impairment during the short-term in which they occasionally use the drug but that after six months or more of abstinence, their performance on the same cognitive tests used to identify those changes returns to being indistinguishable from the performance of those who have never been exposed to the drug (Golding, Groome, Rycroft, et al., 2007). The Short-Term and Long-Term Consequences of Heavy MDMA Use

Animal studies have conclusively established that MDMA causes permanent destruction of neurons and synaptic processes that are essential to the physiological mechanisms of neurotransmitter secretion, response, and reuptake by virtue of the selectively neurotoxic properties of the drug on 5-HT neurons in rats (Verrico, Miller, & Madras, 2007). Those findings are consistent with anecdotal evidence collected from clinical human data in connection with the long-term cognitive, behavioral, and mood regulation functions of repeated MDMA users (Roiser, Rogers, & Sahakian, 2007). However, studies based on data from humans have been limited by the inherent difficulty of isolating the effects of (just) MDMA from that of other recreational drugs since MDMA users typically experiment with other illicit drugs, such as cannabis and cocaine, as well. Another inherent difficulty and limitation of those studies is that some of the mood differences (particularly in relation to impulsivity) may be contributing causes of drug use rather than results of drug use, much less of any specific drug. While acknowledging those complexities associated with the research, it appears that after controlling for other types of drug use, the results suggest that only heavy and long-term use of MDMA is necessarily linked to permanent changes in brain physiology of sufficient significance to produce measurable behavioral changes. Generally, the light or occasional use of MDMA does not appear to result in the same types of cognitive changes (Roiser, Rogers, & Sahakian, 2007).

The Consequences of MDMA Use by Pregnant Mothers

Some of the most serious implications of the recreational use of MDMA have to do with its use by pregnant mothers (Koprich, Chen, Kanaan, et al., 2003). Specifically, rat pups born to mothers exposed to MDMA during the gestational period that corresponds to neurological and neurotransmitter process...

On the basis of the results, the researchers hypothesized that MDMA exposure decreased the release of dopamine or serotonin, reduced enzymatic activity in the brain, or increase dopamine neuron innervation (Koprich, Chen, Kanaan, et al., 2003).
Conclusion

There is no question that heavy recreational use of ecstasy is detrimental to human health. It is responsible for the destruction of vital neurological tissue necessary for proper neurotransmitter processes that regulate mood and other cognitive processes. The results of empirical animal studies mirror the anecdotal clinical human data in that regard. However, cognitive testing of long-term heavy MDMA users and short-term light MDMA users reveals that light use only affects cognitive functions in the short-term after which they return to normal following prolonged cessation of use. On the other hand, animal studies of the vulnerability of infants to in-utero MDMA exposure reveals that it is associated with significant detrimental changes that likely correspond directly to human subjects as well. The obvious implications are that heavy recreational use of MDMA should be avoided and that the use of MDMA by pregnant mothers must be avoided at all costs.