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 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 […]

Changing Patterns of Cocaine Use: Longitudinal Observations, Consequences, and Treatment

In 1858 the Austrian frigate Novara was sent to South America on a most unusual mission. The Novara was named after the city in which the Austrians had defeated the Italians, thereby stopping a threatening cultural and political renaissance. On board the Novara was a trade expert, Doctor Scherzer, who was intrigued by another Italian “renaissance” started by Milan neurolgist Paola Mantegazza. Mantegazza had published an 1857 paper proclaiming the medical importance of coca that he had chewed while a resident of Peru (Mantegazza 1857). The paper was the newest curiosity of the European medical community which even awarded Mantegazza a prize for this work in 1859 (Mortimer 1901). The Novara stopped in Peru and Scherzer took a quantity of coca leaves back to the great chemist Wohler at the University of Gottingen in Germany. Wohler’s assistant, Albert Nieman, named the isolated alkaloid “cocaine” in 1859/1860 (). The isolation and naming of the alkaloid signalled the start of 125 years of changing patterns of cocaine use. Prior to that time, only coca products were available, and the patterns of their use had not changed substantially in over 4700 years. For most of its early history, cocaine remained hidden Read more […]

Cocaine: Short-term observations of users (1970-1983)

A number of studies have provided observations of contemporary patterns of cocaine use in the period 1970 to 1983. These studies have concentrated on selected populations of users that were seen at only a single point of time during this period. When reviewed chronologically, these observations suggest that patterns of cocaine use were changing rapidly throughout the period 1970 to 1983 and in particular for long-term users. For individuals engaged in continued use this change was characterized by increased dosage and frequency of use resulting in decreasing positive effects and increasing negative reactions including physical and psychological dysfunction. This changing pattern is also examined () in a series of longitudinal observations made on a sample of users studied at multiple points of time during this sane period. Users entered the 1970s with attitudes that supported their beliefs that cocaine was a “safe recreational drug.” Gay and Inaba () suggested that the rediscovery of cocaine in the 1970s was inevitable because its effect of euphoria and stimulation “reinforces and boosts what we recognize as the highest aspirations of American initiative, energy, frenetic achievement, and ebullient optimism” (). Phillips Read more […]

Cocaine: Longitudinal study of users (1975-1983)

Methods A total of 118 cocaine users were recruited for study in 1974. Of these, 19 were selected for interview and questionnaire study while 99 (85 males, 14 females) were selected for a more comprehensive longitudinal study. All 99 users (18-38 years old) were social-recreational users who met the initial requirement of having used a minimum of 1 gram of cocaine per month for 12 months (range 1-4 grams). The majority of users were students (73 percent,) while others listed their occupations as housewives, business people, writers, attorneys, physicians, secretaries, teachers, or unemployed. Exaninations and tests were performed on each subject at 6-month intervals for 4 years (1975, 1976, 1977, 1978) and then at approximately 18-month intervals for another 5 years. Examination procedures included a personal history questionnaire, drug history questionnaire, subjective drug effects questionnaire, mental status exanination, the Minnesota Multiphasic Personality Inventory (MMPI), the Experiential World Inventory (EWI), in-depth interviews, and physical examinations (for most subjects). In addition, assays were performed on samples of cocaine used by these subjects. An important caveat is that a number of users dropped Read more […]

Human Dependence on Tobacco and Opioids: Common Factors

Recent years have seen increasing acceptance of the notion that tobacco is an addictive or dependence-producing substance, particularly as it is used in cigarette smoking. This idea is supported by the observations that tobacco serves as a reinforcer (i.e., it maintains behavior leading to its use) and that most people who smoke cigarettes would like to quit but cannot, even in the face of well documented health risks and economic sacrifices (Surgeon General’s Report 1979). The term “drug dependence” suggests that (1) the drug serves as a reinforcer, (2) behavior occurs which is maintained by the opportunity to take the drug, and/or (3) other reinforcers are sacrificed as a consequence of taking the drug (). Many cigarette smokers in some degree satisfy these criteria for drug dependence (). Since cigarette smoking has only recently been conceptualized as an instance of drug dependence, it should be useful to systematically compare cigarette smoking with another more thoroughly studied dependence process such as opioid dependence or narcotic addiction. At first blush, cigarette smoke and opioid drugs appear to produce vastly differing pharmacological and behavioral effects: large doses of opioids can produce Read more […]

Differential Drug Effects as a Function of the Controlling Consequences

One of the central themes during the initial period in the development of behavioral pharmacology was the issue of whether motivational factors influence the effects drugs have on behavior. Though seemingly a straightforward question, the translation of this problem into an experimentally addressable form was, and continues to be, somewhat difficult. Motivational concepts almost inevitably pose formidable experimental problems, and studies designed to resolve those problems have often yielded equivocal results. Typically, however, the question has been approached experimentally by comparing the effects of various drugs on behavior controlled by different types of events, e.g., food presentation and escape from electric shock. Presumably, different events and the behavioral consequences associated with them engendered different motivational states. The influence of motivational factors as determinants of drug action should then be reflected by differential changes in overt behavior when the organism is given certain drugs. This approach had one rather substantial problem that was not always recognized. Behavioral consequences are important in several different ways, not only when they differ on some hedonic dimension, Read more […]

Drug effects on behavior maintained by food, electric-shock presentation and stimulus-shock termination

Although early experiments did not find differences in drug effects depending on the type of event, more recent studies have reported several instances in which the maintaining event appeared to influence the effects of several drugs on behavior. For example, morphine, methadone, and the narcotic antagonists naloxone and nalorphine decreased responding maintained under 5-minute fixed-interval food-presentation schedules at doses that increased responding comparably maintained by the presentation of an electric shock (). Under similar schedule conditions, both amphetamine () and cocaine () increased responding maintained by these two events. However, appropriate doses of pentobarbital, ethanol, and chlordiazepoxide increased responding maintained by food, while only decreasing responding under shock-presentation schedules (). These findings suggested that there were several conditions under which certain drugs appeared to affect similar performances maintained under comparable schedules in an event-dependent manner. Further, as shown in Figure Effects of chlordiazepoxide on different control rates of responding under S-minute fixed-interval schedules of food or shock presentation. The event pen was defected downward Read more […]

Adverse Effects of Cocaine Abuse

Specific, consequences of cocaine abuse on health and psycho-social functioning were assessed in 55 cocaine-abusing subjects who called a telephone “helpline.” Results showed a high incidence and wide range of adverse consequences including: (a) impairment of job functioning, interpersonal relationships, and financial status; (b) disturbances of mood and cognitive functioning; (c) psychiatric symptoms of depression, paranoia, and increased suicidal/violent tendencies; and (d) physical symptoms of exhaustion, weight loss, sleep problems, and seizures. Cocaine-related automobile accidents, suicide attempts, and violent acts, including a cocaine-related homicide, were also reported. Intranasal users reported no fewer and no less severe adverse consequences than free-base smokers or intravenous users. Our findings challenge popular notions that cocaine is a benign “recreational” drug and that the intranasal route of administration guarantees protection against addictive patterns of use and adverse effects. Introduction Cocaine use has escalated to epidemic proportions in the U.S. in recent years. Nationwide surveys estimate that over 22 million American have used cocaine and the numbers continue to soar at an alarming Read more […]

Multiple Drug Use Epidemiology, Correlates, and Consequences

The initial focus is on the conceptual issues essential to the understanding of multiple drug use. This is followed by a discussion of the developmental nature of multiple drug use and the various strategies that have been designed to measure multiple use. The third section of the paper contains a review of the extent of multiple drug use in various segments of society with data from the Monitoring-the-Future surveys of high school seniors, the National Survey on Drug Abuse, and the Treatment Outcome Prospective Study of drug abuse treatment clients. The conclusion is that multiple drug use is pervasive. The next section deals with several consequences associated with multiple drug use: automobile accidents, delinquency, and emergency room visits. The final section outlines some of the prevention and treatment implications of multiple drug use from a public policy perspective. In a study of the effects of a single drug upon behavior, the implications are manifold. Dosage levels, modes of administration, baseline states, the expectations of the subjects and of the investigators, the environment in which the drug is taken — all these variables, and others as well, make human psychochemical studies difficult and complex. Read more […]