Marijuana acute effects

Cone EJ, Johnson RE, Moore JD, Roache JD. (1986). Acute effects of smoking marijuana on hormones, subjective effects and performance in male human subjects. Pharmacol Biochem Behav. 24(6) 1749-54. 

Block, R.I., Farinpour, R., and Braverman, K., Acute effects of marijuana on cognition relationships to chronic effects and smoking techniques, Pharmacol. Biochem. Behav., 43, 907, 1992. 

Consequences of the short-term effects of marijuana can greatly influence a teen s future life. Short-term acute effects describe a condition that is temporary and short-lived longterm chronic effects are cumulative and can last a lifetime. Many studies document the acute and chronic health consequences of smoking marijuana. For instance, there are consistent reports that marijuana temporarily impairs short-term memory and learning. This is confirmed by users of marijuana outside the... 

Acute effects of THC can be severe but are usually short-lived and temporary. Current literature documents THC s temporary effect on health, suggesting that once the use of marijuana ceases, a rapid recovery from the drug s effects typically occurs. 

A THC tetrahydrocannabinol is the major psychoactive ingredient in the Cannabisplant. A THC is responsible for both the psychiahic and therapeutic effects obtained from marijuana. Its receptor, the cannabinoid receptor, is located mainly tat the presynaptic gap. The areas of the brain most affected are the basal ganglia, cerebellum, cerebral cortex, and the hippocampus. The acute effects consist of degradation in short term memory, changes in sensory perception, reduced concenhation, disturbances in motor abilities, hypothermia, increased blood pressure and heart rate, and reduced pain perception. 

The vast majority of cardiovascular effects associated with cannabis smoking were described earlier in this section as short term (or acute). No evidence shows that smoking marijuana produces deleterious cardiovascular effects among healthy individuals. The acute effects produced (for example, increased heart rate) are, however, potentially dangerous among persons who have existing cardiovascular problems, such as abnormal heart functioning or atherosclerosis. 

The acute effects of marijuana generally are benign. They include bloodshot eyes, increased heart rate and pulse rate, and decreased motor activity. 

F Although marijuana use does cause short-term increases in heart rate and pulse rate, no evidence shows that marijuana smoking produces deleterious cardiovascular effects in healthy individuals. The acute effects may be dangerous to individuals who have preexisting cardiovascular problems. 

The cerebellum is likely to be involved in the psychoactive effects of marijuana. The effects of cannabinoids on rCBF in the cerebellum are consistent with interactions between cannabinoids and the high concentration of CBi receptors in this brain area. Both acute marijuana intoxication and habitual use have been shown to affect parameters such as motor coordination, proprioception, and learning. 

Adams AJ, Brown B, Haegerstrom-Portnoy G, Horn MC (1976) Evidence for acute effects of alcohol and marijuana on color discrimination. Percept Psychophys 20 119-124... 

This chapter summarizes the methods and results of studies in which the author examined the acute or chronic effects of marijuana on human associative processes and memory. Eleven tests used to assess marijuana s effects on associative processes, semantic memory, and episodic memory are described. 

Key Words A -tetrahydrocannabinol acute effects associative processes chronic effects constrained associations episodic memory free associations free recall human learning marijuana memory paired-associate learning reaction time recall retrieval semantic memory THC. 

In the studies of acute effects (1-5), marijuana was administered by smoking under double-blind conditions. The research assistant guided the subject in paced smoking procedures. Cigarettes that contained either 10 mg or 19 mg of A -tetrahydrocannabinol (THC) were compared with placebo cigarettes that contained inactive, cannabinoid-extracted marijuana with only trace amounts of THC. In the studies of chronic effects (6,7), chronic marijuana users were compared with nonusers, i.e., control subjects. In the initial study of chronic marijuana users (6), these users were also grouped according to frequency of marijuana use. 

Effects of chronic marijuana use on semantic memory were not assessed because the studies of acute effects, which were conducted earlier, did not show any marijuana-induced changes in semantic memory-retrieval mechanisms. 

Relatively few human imaging studies have evaluated the effects of marijuana or THC on metabolism or blood flow. Acute intravenous THC in both normal controls and habitual marijuana users led to increased an increased regional cerebral metabolic rate (CMR) in the cerebellum. This increase is positively correlated both with concentrations of THC in the plasma and with the intensity of the subjective sense of intoxication [5]. In a 1997 PET/[lsO]water study with 32 abusers [6], THC dose-depend-ently increased cerebral blood flow (CBF) in the frontal regions, insula... 

The average increase in rCMR after THC administration was less in marijuana users than in controls, and users had lower cerebellar metabolism than the controls at baseline [8]. Thus the cerebellum shows the greatest metabolic increase in response to acute THC and responds to chronic marijuana exposure with a decrease in baseline CMR. Habitual users but not controls responded to THC administration with increased rCMR in prefrontal cortex, orbitofrontal cortex, and basal ganglia. In contrast to the robust effects of THC on relative rCMR, changes in global CMR in response to THC were quite variable, with increases, decreases, and no changes seen in equal numbers of subjects. There was also variability in subjective effects, which were pleasurable for most subjects but either minimal or unpleasant (anxiety or paranoia) for others. 

Hart CL, van Gorp W, Haney M, Foltin RW and Fischman MW (2001). Effects of acute smoked marijuana on complex cognitive performance. Neuropsychopharmacology, 25, 757-765. 

Aii SF, Newport GD, Scaiiet AC, Pauie MG, Baiiey JR, Siikker W Jr. (1991). Chronic marijuana smoke exposure in the rhesus monkey IV. Neurochemicai effects and comparison to acute and chronic exposure to deita-9-tetrahydrocannabinoi (THC) in rats. Pharmacol Biochem Behav. 40(3) 677-82. Bachman JA, Benowitz NL, Herning RI, Jones RT. (1979). Dissociation of autonomic and cognitive effects of THC in man. Psychopharmacology (Berlin). 61(2) 171-75. 

Hooker WD, Jones RT. (1987). Increased susceptibility to memory intrusions and the Stroop interference effect during acute marijuana intoxication. Psychopharmacology (Berlin). 91(1) 20-24. 

Tashkin, D.P., Shapiro, B.J., and Frank, I.M. Acute pulmonary physiologic effects of smoked marijuana and oral A -tetrahydro-cannabinol in healthy young men. N. Engl. J. Med. 289 336-341, 1973. 

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