Teens Who Use Marijuana
at Risk of Schizophrenia

In a preclinical study, researchers from Western University in Ontario, Canada, studied the effects of long-term exposure to THC in both adolescent and adult rats.

They found changes in behavior as well as in brain cells in the adolescent rats that were identical to those found in schizophrenia. These changes lasted into early adulthood long after the initial THC exposure.

The young rats were “socially withdrawn and demonstrated increased anxiety, cognitive disorganization, and abnormal levels of dopamine, all of which are features of schizophrenia,” according to the article. The same effects were not seen in the adult rats.

“With the current rise in cannabis use and the increase in THC content, it is critically important to highlight the risk factors associated with exposure to marijuana, particularly during adolescence,” the researchers warn.

Read Medical News Today story here. Read study abstract in the journal Cerebral Cortex here.

Marijuana Has Become a Media Darling,
But Are Journalists Too Soft on Pot?

Marijuana reporter Joel Warner asks if the media is currently biased in support of marijuana legalization.

He cites a recent incident brought to his attention by Kevin Sabet, founder of SAM (Smart Approaches to Marijuana), who had received a tip that the next-day release of the 2014 National Survey on Drug Use and Health would show that marijuana use in Colorado has reached the highest levels in the nation. Sabet wrote a press release which fell on deaf ears. A Google analysis shows only 17 stories were written about this consequence of legalization in Colorado.

In contrast, a few weeks before, the release of the 2015 Monitoring the Future Survey showed a slight downturn in past-month marijuana use among 8^th, 10^th, and 12^thgrade students nationwide. It was hyped by some in the press as a signal that legalization is of no consequence. A total of 156 news stories covered the results of this survey.

Warner notes that there are now “marijuana-business newspapers and marijuana culture magazines, full-time marijuana-industry reporters (this writer included), and even a marijuana-editorial division at the Denver Post called the Cannabist, staffed with a marijuana editor and cannabis strain reviewers,” like Jake Browne, pictured above.

He asks if the data supports it, could marijuana journalists “be expected to conclude that legalization has been a failure, if that means they would also be writing the obituaries for their own jobs?”

Read Joel Warner’s thoughtful International Business Times article here.

Twins Study Finds No Evidence that
Marijuana Lowers IQ in Teens

Two recent studies, one in Great Britain and this one from the University of Southern California, contradict the findings of a rigorous 25-year-long study done with a birth cohort in Dunedin, New Zealand a few years ago. That study found that persistent marijuana use that continued into adulthood resulted in an 8-point drop in IQ. The two new studies find the opposite.

The UCLA study looked at 789 pairs of adolescent twins from two ongoing studies—one in Los Angeles and one in Minnesota—who enrolled between ages 9 and 11. Over 10 years, five IQ tests were administered along with confidential surveys of marijuana use. Marijuana-using twins lost 4 IQ points, but so did their non-using twins, leading researchers to conclude that something other than marijuana was lowering IQ.

The other study compared teens who reported daily marijuana use for six months or longer with teens who used the drug less than 30 times and found no difference in IQ.

But critics say both studies are flawed in that they did not measure heavy marijuana use over a long 25-year period like the Dunedin study did.

Dr. Madeline Meier, lead researcher of the Dunedin study, writes, “Our 2012 study (Meier et al. PNAS 2012) reported cognitive decline among individuals with a far more serious and far more long-term level of cannabis use. That is, we found cognitive decline in individuals followed up to age 38 who started cannabis use as a teen and who thereafter remained dependent on cannabis for many years as an adult. This new study is different; the two papers report about completely different doses of cannabis, and about participants 2 decades apart in age.  The new study reports cognitive test scores for individuals followed up to only age 17-20, fewer than half of whom had used cannabis more than 30 times, and only a fifth of whom used cannabis daily for > 6 months. This new study and our prior study agree and both report the same finding: no cognitive decline in short-term low-level cannabis users. The message from both studies is that short-term, low-level cannabis use is probably safer than very long-term heavy cannabis use. The big problem remains that for some teens, short-term low-level teenaged cannabis use leads onward to long-term dependence on cannabis when they become adults. That is what is cause for concern.”

Read Science story here. Read Dr. Meier’s rebuttal here.