The strongest evidence regarding cannabis and memory focuses on its temporary negative effects on short-term and working memory.In a 2001 study looking at neuropsychological performance in long-term cannabis users, researchers found "some cognitive deficits appear detectable at least 7 days after heavy cannabis use but appear reversible and related to recent cannabis exposure rather than irreversible and related to cumulative lifetime use". On his studies regarding cannabis use, lead researcher and Harvard professor Harrison Pope said he found marijuana is not dangerous over the long term, but there are short-term effects. From neuropsychological tests, Pope found that chronic cannabis users showed difficulties, with verbal memory in particular, for "at least a week or two" after they stopped smoking. Within 28 days, memory problems vanished and the subjects "were no longer distinguishable from the comparison group". Researchers from the University of California, San Diego School of Medicine failed to show substantial, systemic neurological effects from long-term recreational use of cannabis. Their findings were published in the July 2003 issue of the Journal of the International Neuropsychological Society. The research team, headed by Dr Igor Grant, found that cannabis use did affect perception, but did not cause permanent brain damage. Researchers looked at data from 15 previously published controlled studies involving 704 long-term cannabis users and 484 nonusers. The results showed long-term cannabis use was only marginally harmful on the memory and learning. Other functions such as reaction time, attention, language, reasoning ability, perceptual and motor skills were unaffected.
A 2012 systematic review found although it was difficult to draw firm conclusions, there was some evidence that prenatal exposure to cannabis was associated with "deficits in language, attention, areas of cognitive performance, and delinquent behavior in adolescence". A report prepared for the Australian National Council on Drugs concluded cannabis and other cannabinoids are contraindicated in pregnancy as it may interact with the endocannabinoid system. Effects in pediatrics
Children can become exposed to cannabis, typically through accidental exposure which can lead to very high doses, especially in the case of edibles. Unlike in adults, these levels of exposure can lead to major complications in children. These complications include encephalopathy, hypotension, respiratory depression severe enough to require ventilation, somnolence, coma, and there have been case reports of death. Pediatric exposure to edibles is of increasing concern because these products are typically sweets (gummies, cookies, etc. ), and their prevalence is increasing as cannabis is legalized or decriminalized in many territories. See also
Cannabis smoking
Psychoactive drug

References
Further reading
National Academies of Sciences, Engineering, and Medicine (2017). The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. National Academies of Sciences, Engineering, and Medicine. Washington, DC: The National Academies Press. doi:10.17226/24625. ISBN 978-0-309-45304-2. PMID 28182367. {{cite book}}:  CS1 maint: multiple names: authors list (link)