Professor Jennifer D. Thomas, co-director of the Center for Behavioral Teratology at San Diego State University who co-authored the rodent study told Newsweek: "Although it has been known that prenatal alcohol exposure can adversely affect later behavioral development, this study suggests that prenatal cannabis exposure can also influence behavioral development, and that effects may be more severe when combined with alcohol.
"These results are important, as pregnant women may not be aware that cannabis could be harmful to their child," warned Thomas.
Gregory Cole, Professor and Chair of the Department of Biological and Biomedical Sciences at North Carolina Central University who co-authored the zebrafish study, told Newsweek: "This study is significant because it indicates that exposure of embryos to even small amounts of alcohol and cannabis during development may have long-term effects on behavior, with alterations in behavior being exhibited during adolescence.
Today, a new study published in the journal Addiction found that living near a marijuana dispensary increases the likelihood of marijuana use and frequency of use among young people aged 18-22.
“This study proves if you live near pot shops and their ads, you’re more likely to use marijuana,” said Dr. Kevin Sabet, president of Smart Approaches to Marijuana (SAM) and a former senior drug policy advisor to the Obama Administration. “It proves what parents and teachers have been saying for decades: commercialization increases drug use.”
BACKGROUND: Cannabinoids are among the psychoactive substances considered as alternatives to opioids for the alleviation of acute pain. We examined whether self-reported marijuana use was associated with decreased use of prescription opioids following traumatic musculoskeletal injury.
METHODS: Our analysis included 500 patients with a musculoskeletal injury who completed a survey about their marijuana use and were categorized as (1) never a user, (2) a prior user (but not during recovery), or (3) a user during recovery. Patients who used marijuana during recovery indicated whether marijuana helped their pain or reduced opioid use. Prescription opioid use was measured as (1) persistent opioid use, (2) total prescribed opioids, and (3) duration of opioid use. Persistent use was defined as the receipt of at least 1 opioid prescription within 90 days of injury and at least 1 additional prescription between 90 and 180 days. Total prescribed opioids were calculated as the total morphine milligram equivalents (MME) prescribed after injury. Duration of use was the interval between the first and last opioid prescription dates.
CONCLUSIONS: Our data indicate that self-reported marijuana use during injury recovery was associated with an increased amount and duration of opioid use. This is in contrast to many patients' perception that the use of marijuana reduces their pain and therefore the amount of opioids used.
Earlier this year, our laboratory published work demonstrating that rats whose mothers were given low-dose THC (or an analogous synthetic cannabinoid) while pregnant showed significant changes in synaptic plasticity and altered levels of several important proteins lasting well into adulthood. We found that the consequences of these changes manifested as a reduced sociability in the exposed offspring. Male rats in particular were much less likely to approach, play with, or sniff other rats.4
These findings parallel sociobehavioral changes seen in young adult humans exposed to cannabis during gestation. And scientists are now linking those effects to changes in the brain that are similar to what we observed in rats. Using functional MRI technology, for example, researchers participating in the Ottawa Prenatal Prospective Study observed a reduction in activity in the prefrontal cortices of adult offspring of mothers who smoked marijuana during pregnancy. This drop was associated with decreased working memory, echoing the attentional problems and memory dysfunction seen as early as infancy.5
Cannabis is also likely to affect the amygdala, which is critical for emotional development. In 2004, Yasmin Hurd of the Karolinska Institute and colleagues identified a significant reduction in dopamine D2 receptor mRNA in the amygdalae of fetal brains that correlated with the reported quantity of cannabis consumed by their mothers.6 (The fetuses were all between 18 and 22 weeks of gestation and donated by women who underwent voluntary abortions.) Given the known role of amygdala dopamine signaling in the regulation of mood and emotion, these findings could explain the increased depressive-like symptoms observed in children following cannabis exposure in utero, as well as these kids’ propensity towards inattention and impulsivity.
The problem of infant cannabis exposure extends well beyond pregnancy. THC and its lipophilic cannabinoid analogs are readily transferred through breast milk of humans and other mammals, and animal studies have pointed to these compounds’ influence on development throughout the pre-weaning period. Worse yet, given that these cannabinoids linger in the body for weeks, the “pump-and-dump” approach often employed to avoid feeding alcohol-laden milk to an infant isn’t as effective for cannabis users—a Friday night joint can continue to deliver active cannabinoids through breast milk throughout the weekend and into the next week.