The study and of the effects of cannabis as with most drugs, has been ambiguous and controversial. Numerous assertions have been made claiming it has very negative effects for example, in the 1930’s American officials began claiming that cannabis causes permanent brain damage, insanity, criminality, aggression and sexual deviancy. From the 1950’s onward it was argued that its negative effects included psychological dependence, the use of other more dangerous drugs and psychosis (Grilly, 2006).
Due to such controversy surrounding cannabis there is always the risk of experimenter bias, either in favour or against the drug, as well as poor methodology, e. g. one study by Heath seemed to have found brain damage in Rhesus monkeys, in the study cannabis was administrated through marijuana smoke in a mask, however in the experiment oxygen was also removed from the mask, and oxygen deprivation can lead to brain damage it is deprived for long enough.
Due to such poor methodology and exaggerated claims, both negative and positive, it is important to quickly review the psychological effects of cannabis. Psychological Effects In a review by Hollister (1986) the acute psychological impact of cannabis includes an increased appetite (increased sweet consumption- Foltin et al, 1986), a period of euphoria, commonly referred to as being ‘stoned’, which is usually followed by drowsiness. He also noted that the literature included findings of individuals sense of time being altered, having less discriminant hearing and having sharper vision.
Disruptions in cognitive processes are also reported, e. g. thinking, attending and speaking. According to Hooker & Jones (1987, cited in Grilly, 2006) it is the impairment of memory which results in deficits in other cognitive functions, as demonstrated in numerous cognitive tasks. However it has also been noted by Cami et al (1991, cited in Grilly, 2006) that cannabis’ effect on an individual’s motivation to do well may be the reason for impaired performance on cognitive tasks.
An example of when someone may be motivated to perform well is in simulated and actual driving tests, where cannabis has been found to make the drivers focus more to compensate for the detrimental effects of cannabis intoxication (Zimmer & Morgan, 1997, cited in Grilly, 2006). Sexual experiences can also be improved or even suppressed by cannabis, the effect appears to be dependent on one’s culture (Grilly, 2006).
The psychological effects of cannabis are as shown, numerous, but there are also numerous factors that influence these effects such as how the drug was administrated, the potency, it’s effects in the brain and social factors. Marijuana and administration Marijuana itself is not the drug, it is the plant, and it contains chemicals (known as cannabinoids) that are specific to cannabis, of which the major psychoactive chemical is delta-9-tetrahydrocannabinol (THC).
An individual’s ability to control the adjustment of the rate of the dose by the user to attain optimal effects while avoiding negative effects is known as autotitration. The potency of cannabis and therefore its psychological effects vary, a typical joint contains 4. 1% THC but sinsemilla and hashish can contain three times the amount of THC (Grilly, 2006). In humans the main routes of administrating cannabis for recreational purposes is through smoking and oral consumption. When marijuana is smoked, a portion of the THC is lost by smoke escaping into the air.
The amount of THC delivered to the brain by smoking is around 18%, 23% for experienced users and around 10% for amateur users. The absorption of the THC via smoking is rapid, as it travels directly from the lungs to the brain, and the onset of symptoms occurs in minutes (Lindgren et al. , 1980, cited in Hollister, 1986). Oral administration results in only 6% being absorbed being about one third the potency, but requires 2 hours for the symptoms to set in, there is also a prolonged span of time in which the symptoms last (Lemberger et al., 1974, cited in Hollister, 1986).
According to the NHS on its web page on cannabis is the most widely used drug in Britain (NHS- Cannabis), as the case with most other countries. Many users of cannabis report that over time of continued use, they get a greater effect from it, though this may be due to receiving a smaller of dose of THC when they first use it and with more experience the dose increases, this is idea is supported by the Lindgren et al. (1980) who found the doses of experienced marijuana smokers to be 8% higher than the doses of infrequent users.
Sociodemographic factors A study conducted by Sydow et al. (2002) found that family influences were of great significance in the use of cannabis, supporting other research suggesting that growing up without either parent or being at a young age when parents’ divorce is a factor influencing the use of cannabis. Also they found that people in a disadvantaged socio-economic environment were more likely to use high levels of cannabis and develop dependence, and has been suggested as a way from escaping from such an environment in the same manner as alcohol.
The social factor of peer groups pressuring individuals to take cannabis was also found as well as availability, both factors showed a person would be more likely to use cannabis but not more likely to develop dependence. Pharmacodynamics of Cannabis Cannabis can remain detectable in the body for weeks, which is possible because of its high lipid-solubility, some researchers suggest that this is an important factor in its effects because it means it could build up in the body.
Though Hollister (1986) makes a point which is more likely to be true, citing adipose tissue as being the most likely place for it to accumulate and because physiologically it makes up around 15-20% of the human body there would not be a major psychological impact. This could a lot mean that fatter humans could store more THC meaning the THC would have less effect, though this is simply conjecture. It is also important to note that because cannabis is lipid-soluble, it could be used in baking as a form of recreational administration (Iverson, 2000).
THC has been found to exert a significant effect on two types cannabinoid receptors (CB1 and CB2), both of which are G-protein coupled receptors. The CB1 receptor is found in the brain while the CB2 receptor is found in the peripheral tissues. Based on neuroimaging studies, CB1 receptors appear to have high densities around the frontal cerebral cortex, in the basal ganglia and in the cerebellum. The hippocampus also contains a rather high density of the CB1 receptors, which is a potential explanation for why memory is impaired by cannabis, since the hippocampus has a function in storing new memories (Iverson, 2003).
The CB1 receptor appears to have mood and cognition altered by THC acting on it. There is some evidence of the existence of a reward system in the brain for THC, as it has been found to increase dopamine release (Grilly, 2006). Dependence Grilly (2006) describes someone who is willing to intake cannabis as people …“who are not particularly anxious about the unfamiliar or the unconventional or about loss of control and the unpredictability of their world may find such effects pleasurable, as long as they can retain control over the time and degree of these effects”.
However some people may lose control and as seen in “A brief history of controversy” it has been claimed that it can lead to addiction. Grilly (2006) states that cannabis dependence is primarily psychological one, due to its ability to alter a person’s mood and cognitive functions. Haney et al. (1999) reported that when participants’ cessed smoking marijuana cigarettes, signs of withdrawal emerged, however the symptoms must have been mildly uncomfortable because not one participant asked to withdraw.
This suggests that the psychological dependency is quite weak and the degree of controllability in taking cannabis is high, which is supported by a definition by Miller & Gold (1989):a) preoccupation with getting the drug, b) compulsive use and c) recurrent use even after attempting to quit, based on this very few cannabis users meet this criteria. Conclusion The factors influencing the psychological effects of cannabis are numerous.
Overall the study of set and setting for studying addiction is important for any drug prevention and treatment strategies because it allows the causal factors to be reduced and treatment can be tailored for individual need. References Cami, J. , Guerra, D. , Ugena, B. , Segura, J. , & de la Torre, R. : Effect of subject expectancy on the THC intoxication and disposition from smoked hashish cigarettes. Pharmacology, Bio-chemistry and Behaviour, 40: 115-119, 1991. Foltin, R. W. ; Brady, J. V. ; and Fischman, M. W. : Behavioural analysis of marijuana effects on food intake in humans.
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