By Frances E. Jensen

The recent news story about 12 Wesleyan students who had been hospitalized after taking Molly - also known as ecstasy or MDMA - caught my eye because one of my sons recently graduated from Wesleyan. It's a fantastic school, filled with really bright students and gifted professors.

Given what neuroscience can tell us about the short- and long-term effects of potent drugs like Molly on the less-than-adult brain, it is highly disturbing to see widespread, socially very acceptable use on college campuses and in nightclubs. Don't these students understand the risks? The answer appears to be a resounding No.

Being a researcher of the neurobiology of the developing brain, I know well the basic research confirming the enhanced hazards of neuroactive substances on the teenage and young adult brain. The brain is very much still under construction until the mid- to late 20s.

It turns out that one way the brain is not fully developed is that, compared with an adult, there is less frontal-lobe connectivity and hence more risk-taking behavior (independent of book smarts). In addition, neurons and their synapses are more active and susceptible to both good and bad stimuli at this age, making teens and young adults more vulnerable to toxicity.

Information from research laboratories world-wide has shown that MDMA has toxic effects on the brain and that these are highly unpredictable. What's more concerning is that many laboratories are showing that teen and young adult brains are far more vulnerable to acute brain damage than older adult brains.

MDMA acts on the brain by increasing the release of our natural serotonin and dopamine neurotransmitter receptors - the "feel good" system - producing a sense of euphoria and an artificial sense of reward. People with depression, for instance, have lower levels of serotonin, and many antidepressants are designed to increase brain levels of this neurotransmitter.

The problem with MDMA is that the overactivation of these neurons can lead to the depletion of this system and actual death of the cells that normally produce these chemicals. The serotonin and dopamine systems are in a critical period of development in the teen and young adult years, so they are exquisitely vulnerable to toxic effects. Indeed, recreational users, especially those in the adolescent and early adult years, can suffer from long-term cognitive and memory problems.

Worse yet, MDMA use has been shown to unpredictably cause injury in key areas of the brain for memory, such as the hippocampus. This toxicity seems to have a peculiar predilection for the young adult.

Taking this one step further: Many young people tend to mix MDMA with alcohol and binge drinking. Once again, contrary to popular belief, the adolescent brain has been shown to be more sensitive to injury from alcohol toxicity than the adult brain. Recent reports also show a deadly synergy between alcohol and MDMA in the adolescent brain, with the combination having more severe effects on long-term memory as well as alterations of the serotonin and dopamine systems.

Thinking about college life, I find it ironic that, at a stage when one is positioned to be a learning machine, recreational substance abuse can permanently disable these fragile circuits.

As a neuroscientist, I remain concerned that this critical information about MDMA toxicity, with or without binge drinking, is not getting mainstream press. The enhanced vulnerability of the younger brain, coupled with the risk-taking tendency, can have lethal or near-lethal consequences, as was demonstrated recently at Wesleyan. Getting the knowledge out there must be part of the solution: These kids need to know that the cost to their brains is too great.

Dr. Frances E. Jensen is chair of the neurology department at the University of Pennsylvania's Perelman School of Medicine and the author of "The Teenage Brain: A Neuroscientist's Survival Guide to Raising Adolescents and Young Adults" (Harper Collins, 2015). frances.jensen@uphs.upenn.edu.