Thursday, August 22, 2013
Synthetic cannabimimetics and psychosis.
Not long ago, public health officials were obsessing over the possibility that “skunk” marijuana—loosely defined as marijuana exhibiting THC concentrations above 12%, and little or no cannabidiol (CBD), the second crucial ingredient in marijuana—caused psychosis. In some cases, strong pot was blamed for the onset of schizophrenia.
The evidence was never very solid for that contention, but now the same questions have arisen with respect to synthetic cannabimimetics—drugs that have THC-like effects, but no THC. They are sold as spice, incense, K2, Aroma, Krypton, Bonzai, and dozens of other product monikers, and have been called “probationer’s weed” for their ability to elude standard marijuana drug testing. Now a group of researchers drawn primarily from the University of Trieste Medical School in Italy analyzed a total of 223 relevant studies, and boiled them down to the 41 best investigations for systematic review, to see what evidence exists for connecting spice drugs with clinical psychoses.
Average age of users was 23, and the most common compounds identified using biological specimen analysis were the now-familiar Huffman compounds, based on work at Clemson University by John W. Huffman, professor emeritus of organic chemistry: JWH-018, JWH-073, JWH-122, JWH-250. (The investigators also found CP-47,497, a cannabinoid receptor agonist developed in the 80s by Pfizer and used in scientific research.) The JWH family consists of very powerful drugs that are full agonists at CB-1 and CB-2 receptors, where, according to the study, “they are more powerful than THC itself.” What prompted the investigation was the continued arrival of users in hospitals and emergency rooms, presenting with symptoms of agitation, anxiety, panic, confusion, combativeness, paranoia, and suicidal ideation. Physical effects can includes elevated blood pressure and heart rate, nausea, hallucinations, and seizures.
One of the many problems for researchers and health officials is the lack of a widely available set of reference samples for precise identification of the welter of cannabis-like drugs now available. In addition, the synthetic cannabimimetics (SCs) are frequently mixed together, or mixed with other psychoactive compounds, making identification even more difficult. Add in the presence of masking agents, along with various herbal substances, and it becomes very difficult to find out which of the new drugs—none of which were intended for human use—are bad bets.
Availing themselves of toxicology tests, lab studies, and various surveys, the researchers, writing in Human Psychopharmacology’s Special Issue on Novel Psychoactive Substances, crunched the data related to a range of psychopathological issues reported with SCs—and the results were less than definitive. They found that many of the psychotic symptoms occurred in people who had been previously diagnosed with an existing form of mental disturbance, such as depression, ADHD, or PTSD. But they were able to determine that psychopathological syndromes were far less common with marijuana than with SCs. And those who experienced psychotic episodes on Spice-type drugs presented with “higher/more frequent levels of agitation and behavioral dyscontrol in comparison with those psychotic episodes described in marijuana misusers.”
In the end, the researchers can do no better than to conclude that “the exact risk of developing a psychosis following SC misuse cannot be calculated.” What would the researchers need to demonstrate solid causality between designer cannabis products and psychosis? More product consistency, for one thing, because “the polysubstance intake pattern typically described in SC misusers may act as a significant confounder” when it comes to developing toxicological screening tools. Perhaps most disheartening is “the large structural heterogeneity between the different SC compounds,” which limited the researchers’ ability to interpret the data.
This stuff matters, because the use of Spice-type drugs is reported to be increasing in the U.S. and Europe. Online suppliers are proliferating as well. And the drugs are particularly popular with teens and young adults. Young people are more likely to be drug-naïve or have limited exposure to strong drugs, and there is some evidence that children and adolescents are adversely affected by major exposure to drugs that interact with cannabinoid receptors in the brain.
Graphics credit: http://scientopia.org/blogs/drugmonkey/