Harmful Effects of Cannabis Smoking on Reasoning Ability, Memory and Sense of Coherence (Cognitive Functions)

After a single instance of intoxication, the acute psychotoxic effects caused by cannabis smoking on cognitive functions (reasoning ability, memory functions, analysis and planning ability, etc.) will remain, in general, for a maximum of four to five hours. The duration of these effects is dependent on the level of THC in the blood, and there is a delay of an hour or so relative to the time of consumption. In the case of repeated consumption, i.e. on one or more occasions per day, the functional impairments will persist (even though the individual learns how to hide certain functional shortcomings) and the entire personality will eventually become marked by above all cognitive difficulties, and also by the social strategies to which the individual has recourse in order to cope. The manifestations of the chronic effects include the following: decreased ability to carry out complex thought operations, reduced ability to concentrate, decreased ability to process information, impairment of short-term memory, reduced intellectual flexibility and ability to learn from experience, lowered ability to carry out long-term strategic planning, and difficulties expressing oneself verbally in new, unfamiliar situations where old Read more […]

Damage to Cognitive Mental Functions While under Chronic Cannabis Influence

b) Damage to Cognitive Mental Functions While under Chronic Cannabis Influence Scientific Studies In 1986, Wert and Raulin made two wide-ranging reviews of all studies that had been carried out in this field up to that point. They found () that neither neurological nor neuropsychological studies had shown unambiguously that chronic abusers suffered from structural or functional damage caused by their chronic abuse. However, Wert and Raulin do discuss the possibility that the “differential impairment” (in groups equally exposed to cannabis abuse and having experienced similar conditions in other respects, some subjects exhibited damage while others did not) found in many studies might not be a consequence of faulty study design but rather a manifestation of varying vulnerability in different individuals. The authors write: It might well be that some individuals are predisposed to cerebral impairment as the result of cannabis use, either because of structural or biochemical characteristics which accentuate the possible damaging effects of the drug, or because they have little of the cerebral reserve that most of us call on when we experience mild cerebral damage. That functional reserve can mask very Read more […]

Cannabis Smoking in Teenagers

Cannabis smoking disrupts the hormonal balance in both men/boys and women/girls. We do not know exactly how this affects teenagers, but the suspicion is that it can reduce fertility. There have been reports of disturbance in growth and of delayed sexual maturity. Cannabis as a gateway to harder drugs: It has long been understood that cannabis use is one of several factors that increase the likelihood of starting to use other illegal drugs. One of the reasons for assuming there to be a causal connection has been that the intensity and duration of a person’s cannabis smoking increase the risk that he or she will move on to harder drugs. Notwithstanding this, it is only recent and methodologically well-conducted studies (including prospective ones of long duration covering a large number of people) that have been able to show that, even after controlling for the effects of other known and suspected factors, there remains a strong association between cannabis smoking and moving on to harder drugs. It would appear that we are close to proving the controversial gateway hypothesis – the hypothesis that, in many cases, cannabis use constitutes a gateway to harder drugs. The development of identity, according to accepted Read more […]

Does Cannabis Abuse Represent a Gateway to Harder Drugs?

The question of whether cannabis represents a gateway to harder drugs has occupied clinicians and researchers for 30 years. The reason for the interest in this question has been that a transition to harder drugs – heroin, amphetamines or cocaine – represents a significant increase in the degree of risk to which the individual is exposed. Even though cannabis is more psychotoxic than heroin, intravenous heroin abuse is in many other respects a considerably more serious condition than cannabis dependence. With heroin – which is also much more expensive than cannabis –, addiction not infrequently develops quickly, the dependence is strong, and mortality is considerably higher, mainly owing to overdoses. It is the rule rather than the exception that heroin-dependent individuals become socially marginalised. The abuse of both amphetamines and cocaine (not least in the form of “crack”) also leads to rapid development of severe dependence, with the risk of a series of mental side-effects and high mortality levels. Moreover, transition to intravenous abuse adds the risk of HIV infection. The most extensive studies in this field have been carried out by Denise Kandel and her research team. They showed, at an early Read more […]

Cannabis Abuse and the Teenager’s Psychosocial Maturation

Cannabis Abuse and Cognitive Development during the Teenage Years In post “Harmful Effects of Cannabis Smoking on Reasoning Ability, Memory and Sense of Coherence (Cognitive Functions)”, there is a discussion of the effects caused by long-term cannabis abuse on cognitive functions. From that discussion, it is clear that cannabis smoking has negative effects on a number of aspects, not least aspects which are of importance for more com plicated thought operations, planning, and the integration of impressions and previous memories, etc. It is worth repeating here that short-term memory is also called working memory, and that it is not just a “memory function” but a central location for the coordination of a number of mental functions which play an important role in enabling individuals to orient themselves relative to the surrounding world, such as planning, reorientation and reacting to new and unexpected circumstances. The scientific studies and clinical observations previously referred to concerned mainly adults; here we will look at what these kinds of cognitive disturbance can entail for teenagers, who are in a dynamic developmental phase. In order to emphasise that teenagers are at least as sensitive Read more […]

Cannabis and Violence

Most researchers agree that the effect of cannabis is normally (i.e. in the case of the average abuser) to calm and to induce passivity rather than to stimulate aggressiveness. However, owing to the dramatic nature of the effects produced by cannabis on the mind and to clinical observations of violent acts, the question of whether cannabis might be associated with aggressiveness and acts of violence has been raised repeatedly. A large number of commissions and conferences have focused on this issue (). In all cases, the conclusion reached has been a similar exonerative verdict of “not guilty”. Abel () does, however, point out that a weakness shared by all these commission reports is that in general, they have not looked at the question of the effect produced by cannabis on individuals who are especially vulnerable in this respect – above all, mentally fragile people with low levels of impulse control and people with psychoses, borderline psychotic conditions, profound personality disorders and brain damage. There seems to be no study that shows, in a methodologically satisfactory manner, that cannabis is in any way linked with violence. The explanation may have something to do with Abel’s above-mentioned Read more […]

Cannabis and Pregnancy

THC is a substance which passes from the mother’s blood to that of the foetus. This means that THC can cause direct damage to the foetus during pregnancy. (THC is also passed on to the infant via breast-milk.) Animal experiments have shown a number of very serious effects on the gestation of, and on the young born to, females which have been given cannabis or THC during gestation. These findings have naturally given rise to questions concerning the risks to which the human foetus is exposed if the mother smokes hashish or marijuana during pregnancy (). Researchers are here confronted with the usual problems of finding a reliable design for their studies, including comparable control groups. Further, research of this type is faced with particular difficulties as regards finding means of excluding other factors that might explain damage that has been observed, such as other drugs (including alcohol and tobacco), inadequate nutrition and infections during pregnancy. Moreover, it is also difficult to find suitable methods of measurement with sufficient sensitivity to detect even damage of a subtle nature. The conceivable – and suspected – harmful effects of cannabis can be divided into the following categories: Effects Read more […]

Cannabis: Friend or Foe?

“Historically, some societies have idealized cannabis whereas others have demonized it and, recently, Western society has tended to oscillate between the two. In reality, as cannabis derivatives have the potential for causing both good and harm, the important question for society is how to maximize the former and minimize the latter” (cited from “Cannabis, the mind and society: the harsh realities” by Murray and colleagues). Cannabis and Mental Illness The majority of recreational cannabis users does not experience serious adverse reactions and is able to regulate their use. However, a minority of frequent or long-term users will develop problems. Abuse and dependence have already been discussed, as well as potential long-term consequences of chronic use for cognitive brain function. But another problem that drew much attention in recent years is the steady increase in mental health problems associated with cannabis use. As other chapters in this book deal with this topic in more detail, I will only give a short overview here. Most of the interest concerning cannabis and mental health issues has focused on psychosis and schizophrenia. Here, the core question is whether cannabis plays an etiological role Read more […]

Measuring the Developmental Nature of Multiple Drug Use

There have been a number of studies in which attempts have been made to measure or assess multiple drug use. Some of these are from general populations while others are focused on specific subpopulations of users. The studies are grouped more on the basis of the approach taken to assessing multiple drug use than on the patterns uncovered. There are at least four different groupings of studies and some studies fit into more than one grouping. Developmental Patterns of Onset of Use One of the most influential attempts to describe patterns of multiple drug use is the “stages of drug use” model developed by Kandel. Kandel posited that persons proceed from licit to illicit drugs and from use of less to more serious drugs. The stages of drug use involvement that she identified were: (1) no use of any drugs; (2) use of beer or wine; (3) use of cigarettes and/or hard liquor; (4) use of marijuana; and (5) use of illicit drugs other than marijuana. Although it is not made explicit by Kandel, there is an implication that the drugs from the earlier stages of development are “carried forward” into the later stages of drug involvement. Thus, a marijuana user is likely to continue his or her use of cigarettes/hard liquor and beer Read more […]

Endocrine Effects of Marijuana in the Male: Preclinical Studies

The research efforts of many investigators in the recent past have made it abundantly clear that exposure to marijuana has significant effects upon the reproductive system and the effects of cannabinoid treatment are equally significant on both male and female reproductive systems. Among the effects of cannabinoid treatment on the male reproductive system that have been reported arc altered testicular function, in the form of depressed male hormone secretion, and changes in both the quantity and quality of the sperm produced by the seminiferous tubules. There have been changes reported in the weight and in certain of the enzymes associated with the reproductive organs. Much research effort focused on the ability of THC to depress the secretion of the gonadotropins from the pituitary that are responsible for stimulating testosterone production by the Leydig cells of the testis and the action on the hypothalamus to depress gonadotropic releasing hormone (GnRH). Maintenance and regulation of normal reproductive capacity in the male is a complex and highly integrated phenomenon. It requires proper nutritional and hormonal support, not only by the hormones directly involved in reproduction, hut also by the synergistic Read more […]