The number of adults and teenagers using THC (organic marijuana and K2/Spice synthetics) appears to be expanding.
The MEDTOX Journal has reported on a succession of scientific reports related to short-term and long-term cognitive effects associated with the use of cannabis. It has been established that cannabis use impairs motivation and executive function; it has also been tied to the lowering of thresholds associated with psychotic symptoms. The relationship of cannabis use and the etiology of schizophrenia is currently the subject of scientific examination. Recently published research in the Journal of Biological Psychiatry explores the impacts that cannabis use has on working memory.
The authors of this study treated 17 healthy subjects with tetrahydrocannabinol (THC) or a placebo who then took tests of working memory that involved an exercise of using short-term memory storage and manipulation of memory. The participants then underwent functional MRI imaging. In the patients receiving placebo, there was evidence of increased and progressive activity in the areas of the brain that are associated with working memory, especially the components that make up the prefrontal cortex. For the participants receiving THC, the effects were the reverse. THC significantly retarded the activity in the prefrontal cortex. The THC-treated patients also exhibited lengthened reaction time and degraded accuracy of recall, all exhibitive of impairment in the prefrontal cortex area. In all, the THC-impaired patients exhibited clear signs of decline in the quality of working memory.
The mounting evidence that marijuana use has serious neuroanatomical consequences must become part of all public service announcements and drug prevention literature. The advent of synthetic cannabinoids makes this situation all the more dangerous as the number of adults and teenagers using THC (organic marijuana and K2/Spice synthetics) appears to be expanding. Based on the societal experience with marijuana to date, it is reasonable to expect that the impacts of synthetic cannabinoids on the brain are decidedly deleterious.
 Bossong MG et al. Effects of ^9-tetrahydrocannabinol in human working memory function. Biol Psychiatry 2012 Apr 15; 71:693-699.