The list of reasons for young adults addicted to marijuana to seek suitable experiential therapy in North Carolina is doubtless a long one, but an addition to that list could be the potential for offspring to have a heightened risk of opiate addiction – even if the drug use ceases prior to offspring being conceived. That is at least the suggestion of the findings of recent animal research.
The study, which was carried out by scientists supported by the National Institute on Drug Abuse (NIDA), showed that rats with parents that had been exposed to marijuana’s main psychoactive ingredient as adolescents were more vigorous seekers of heroin than unexposed animals’ offspring.
The findings cannot be confirmed and explained without further research, but nonetheless back up other studies indicating that even prior to conception, a parent’s history of drug use could affect the brain function and behavior of a child.
Dr. Yasmin L. Hurd and colleagues at the Icahn School of Medicine at Mount Sinai in New York City proposed the hypothesis that if a rat’s parents were exposed during their adolescence to the main psychoactive ingredient in marijuana – delta-9 tetrahydrocannabinol, or THC – the offspring would inherit epigenetic changes that would alter how they responded to heroin.
The researchers tested this hypothesis by injecting THC into adolescent male and female rats for three weeks on an intermittent schedule, corresponding to the amounts that the typical recreational marijuana user would consume – specifically 1.5 milligrams per kilogram of body weight every three days. A two to four week period was allowed for the drug to be washed out of the rats’ bodies, before they were paired and mated.
On the offspring of these matings reaching adulthood, they were presented by the researchers with a lever that delivered heroin amounting to 30 micrograms per kilogram of body weight when pressed. The animals initially self-administered the drug at about the same rates as a group of control animals with parents that were not exposed to THC.
However, when the animals were made to work harder by being required to press the active lever no fewer than five times in order to receive a dose, those whose parents had been subject to drug exposure pressed almost three times as often, on average, as the control rats. More pronounced withdrawal symptoms were also observed among the THC-exposed rats’ offspring when the animals were no longer able to access heroin.
Dr. John Satterlee, Project Officer at NIDA’s Genetics and Molecular Neurobiology Research Branch, commented: “If the effect is real, it’s important. If studies show that marijuana use also shows cross-generational effects in people, those results would add to the known dangers of the drug and amplify the importance of prevention efforts, especially those aimed at youth.”
