Memory cannabis effects

Cannabinoid receptors are expressed throughout the cerebral cortex and the hippocampus, and a subpopulation of these cells appear to show an unusually high level of activity. It is possible that cells in these areas modulate the sensory effects of cannabis, particularly the effects on perception, task performance and memory. In addition, the anticonvulsant properties of cannabis are believed to be mediated here. Parts of the hypothalamus show high levels of receptor sites for cannabinoids this may be related to hypothermia effects. High levels in the cerebellum may be related to mediating the property of cannabinoids that produces the reduction in ataxic (muscle co-ordination) symptoms in certain disorders (Herkenham et al., 1991). 

Miller LL and Branconnier RJ (1983). Cannabis Effects on memory and the cholinergic limbic system. Psychological Bulletin, 93, 441-456. 

Rodgers J, Buchanan T, Scholey AB, Heffernan TM, Ling J and Parrott A (2001). Differential effects of ecstasy and cannabis on self reports of memory ability A web-based study. Human Psychopharmacology, 16, 619-626. 

Some precipitants of HPPD are cannabis use, anxiety, fatigue, and sudden movement into a dark environment. This may be a normal function of memory that becomes exaggerated due to the intense nature of the hallucinogenic experience. Alternately, it may also be a direct pharmacological effect. 

The effects of cannabis on memory was examined in numerous studies, and again the results are variable. For example, fewer words are recalled from a list by subjects administered cannabis compared to placebo, but no effects were seen on a verbal paired-associate learning (Abel 1971 Hooker and Jones 1987). 

Perhaps the most consistent effect of cannabis is consolidation of information from short-term memory (Dornbush et al 1971 Murray 1986). In contrast, cannabis does not appear to impair access to information already in long-term memory (Parley et al. 1977 Parker et al. 1980). While cannabis and placebo groups performed equally well on a word list recognition task, the cannabis group made more false positive errors (Abel 1970, 1971). Another effect on memory reported in severeal studies is increased intrusion of irrelevant material (Abel 1970, 1971 Clark et al. 1970 Tinklenberg et al. 1970 Pfefferbaum et al. 1977). 

A study of experienced cannabis smokers tested them on cognitive measures using two doses (1.75% or 3.55%) and placebo (Wilson et al. 1994). The functions most sensitive to the effects of THC were mental processing speed (digit-symbol substitution) and reaction time. When compared with cannabis nonusers, chronic users of cannabis—with a mean duration of use of 6.76 years and an average daily intake of 150 mg of THC—were found to have slower reactions on perceptuo-motor tasks, but no differences on intelligence or memory tests (Varma et al. 1988). 

Brain cannabinoid receptor. In humans, psychoactive cannabinoids produce euphoria, enhancement of sensory perception, tachycardia, antinociception, difficulties in concentration, and impairment of memory. The cognitive deficiencies persist after withdrawal. The toxicity of cannabis has been underestimated for a long time, since recent findings revealed that A-9-THG-induced cell death with shrinkage of neurons and DNA fragmentation in the hippocampus. The acute effects of cannabinoids, as well as the development of tolerance, are mediated by G protein-coupled cannabinoid receptors. The CBl receptor and its splice variant, CBl A, are found predominantly in the brain with highest densities in the hippocampus, cerebellum, and striatum. The CB2 receptor is found predominantly in the spleen and in hemopoi-... 

CS453 Pope, H. G. Jr., A. Jacobs, J. P. Mialet, D. Yurgelun-Todd, and S. Gruber. Evidence for a sex-specific residual effect of cannabis on visuospatial memory. Psychother Psychosom 1997 66(4) 179-184. 

A9-Tetrahydrocannabinol (A9-THC) is considered to be the predominant compound in preparations of C. sativa (marijuana, hashish, bhang) that is responsible for the central nervous system effects in humans. The recognized central nervous system responses to these preparations include alterations in cognition and memory, euphoria, and sedation. Potential therapeutic applications of cannabis preparations that are of either historical or contemporary interest include analgesia, attenuation of the nausea and vomiting of cancer chemotherapy, appetite stimulation, decreased intestinal motility of diarrhea, decreased bronchial constriction of asthma, decreased intraocular pressure of glaucoma, antirheumatic and antipyretic actions, and treatment of convulsant disorders. These effects have been reviewed recently (Howlett, 1995). 

A review has summarized the evidence related to the adverse effects of acute and chronic use of cannabis (60). The effects of acute usage include anxiety, impaired attention, and increased risk of psychotic symptoms. Probable risks of chronic cannabis consumption include bronchitis and subtle impairments of attention and memory. 

The psychological effects of cannabis vary with personal and social factors. However, some guidance to the essential effects of the drug can be derived from investigations with THC and marijuana in non-user volunteers. Blood concentrations of THC over 75 pg/ml under these conditions are associated with euphoria, and somewhat higher concentrations with dissociation of events and memory and impairment of psychomotor tasks lasting over 24 hours (61). 

The effects of MDMA use on visuospatial memory have been reported in 25 current MDMA users (11 men, 14 women), 10 former users who were abstinent for at least six months (6 men, 4 women), and 18 non-using controls (6 men, 12 women) (86). Both user groups performed more poorly than the controls, even controlled for age, years of education, intelligence, and alcohol and tobacco use. However, when cannabis use was considered, the main effect became non-significant. These results suggest that current and former MDMA users have... 

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