Newswise — As a growing number of U.S. states legalize the medicinal and recreational use of marijuana, an increasing number of American women are using cannabis before becoming pregnant and during early pregnancy often to treat morning sickness, anxiety, and lower back pain. Although emerging evidence indicates that this may have long-term consequences for their babies’ brain development, how this occurs remains unclear.
A University of Maryland School of Medicine study using a preclinical animal model suggests that prenatal exposure to THC, the psychoactive component of cannabis, makes the brain’s dopamine neurons (an integral component of the reward system) hyperactive and increases sensitivity to the behavioral effects of THC during pre-adolescence. This may contribute to the increased risk of psychiatric disorders like schizophrenia and other forms of psychosis later in adolescence that previous research has linked to prenatal cannabis use, according to the study published today in journal Nature Neuroscience.
The team of researchers, from UMSOM, the University of Cagliari (Italy) and the Hungarian Academy of Sciences (Hungary), found that exposure to THC in the womb increased susceptibility to THC in offspring on several behavioral tasks that mirrors the effects observed in many psychiatric diseases. These behavioral effects were caused, at least in part, by hyperactivity of dopamine neurons in a brain region called the ventral tegmental area (VTA), which regulates motivated behaviors.
More importantly, the researchers were able to correct these behavioral problems and brain abnormalities by treating experimental animals with pregnenolone, an FDA-approved drug currently under investigation in clinical trials for cannabis use disorder, schizophrenia, autism, and bipolar disorder.
“This is an exciting finding that suggests a therapeutic approach for children born to mothers who used cannabis during pregnancy,” said Joseph Cheer, PhD, a Professor of Anatomy & Neurobiology and Psychiatry at the University of Maryland School of Medicine. “It also raises important questions that need to be addressed such as how does pregnenolone exert its effects and how can we improve its efficacy? Do these detrimental effects persist into adulthood, and if so, could they also be treated in a similar way?”
The researchers concluded that as physicians caution pregnant women against alcohol and cocaine intake because of their detrimental effects to the fetus, they should also, based on these new findings, advise them on the potential negative consequences of using cannabis specifically during pregnancy.
The study was funded by an international collaborative program on marijuana research issued by the U.S. National Institute on Drug Abuse, the National Research, Development and Innovation Office of Hungary and the University of Cagliari as well as private European foundations.
About the University of Maryland School of Medicine
Now in its third century, the University of Maryland School of Medicine was chartered in 1807 as the first public medical school in the United States. It continues today as one of the fastest growing, top-tier biomedical research enterprises in the world -- with 43 academic departments, centers, institutes, and programs; and a faculty of more than 3,000 physicians, scientists, and allied health professionals, including members of the National Academy of Medicine and the National Academy of Sciences, and a distinguished recipient of the Albert E. Lasker Award in Medical Research. With an operating budget of more than $1 billion, the School of Medicine works closely in partnership with the University of Maryland Medical Center and Medical System to provide research-intensive, academic and clinically based care for more than 1.2 million patients each year. The School has over 2,500 students, residents, and fellows, and more than $530 million in extramural funding, with most of its academic departments highly ranked among all medical schools in the nation in research funding. As one of the seven professional schools that make up the University of Maryland, Baltimore campus, the School of Medicine has a total workforce of nearly 7,000 individuals. The combined School and Medical System (“University of Maryland Medicine”) has an annual budget of nearly $6 billion and an economic impact more than $15 billion on the state and local community. The School of Medicine faculty, which ranks as the 8th highest among public medical schools in research productivity, is an innovator in translational medicine, with 600 active patents and 24 start-up companies. The School works locally, nationally, and globally, with research and treatment facilities in 36 countries around the world. Visit medschool.umaryland.edu