Marijuana and Adolescents
Edward A. Jacobs, MD, FAAP

Introduction
Marijuana is the most common illicit drug used by youth in the United States [1]. There is an increasing body of scientific evidence showing the short term and long term consequences of its use. These consequences are often made more serious because preadolescents and adolescents have not completed their physical, emotional, or social development. Anything that could interfere significantly with that development has the potential for a greater impact than the consequences of similar use by a fully mature and developed adult. This has major implications for the individual teen, his/her family, the school, the community, and the health care professionals whose responsibility it is to care for them. For health care providers, this is true regardless of whether one is a primary care provider, specialist, subspecialist, emergency room provider, or mental health or addiction specialist.

Epidemiology and Patterns of Use
Although the use of marijuana by youth has been trending downward over the past few years, it still remains unacceptably high [1]. In 2005, the “Monitoring the Future” study of almost 50,000 students in 400 schools showed that the lifetime prevalence of marijuana use for 8th, 10th, and 12th graders was 16.5%, 34.1%, and 44.8%. The annual prevalence of use was 12.2%, 26.6%, and 33.6%, and the 30-day prevalence of use for each grade was 6.6%, 15.2%, and 19.8%. The most alarming aspects of these numbers are that approximately 1 in 9 eighth-graders and approximately 1 in 4 tenth-graders are using marijuana once or more per year, that in all categories the use doubles between the 8th and 10th grades, and almost 20% of our high school seniors are using marijuana 1 or more times per month. Furthermore, various studies have cited the age of first use as averaging approximately 13-14 years of age, which means many have started using prior to that age [2,3,4].

Risk and Protective Factors
There are several risk factors which affect the decision to use marijuana by adolescents and preadolescents. These include peer pressure, low self-esteem, history of family use and attitudes toward drug use, isolation, depression and other psychological issues, school failure, and availability of the drug [3,5,11,12]. In fact, drug use has often been referred to as an “infectious disease” because you get it from the people around you. Although school failure, low self-esteem, and emotional disturbance are often cited as risk factors for the use of marijuana and other drugs, the long interval between onset of use and the appearance of significant clinical symptoms including school failure, emotional lability, and more overt psychological and psychiatric symptoms makes it essential to recognize that quite often it is the repeated marijuana use producing these observed behaviors rather than the preexisting behaviors causing the initiation of marijuana use.

One of the most important risk factors for marijuana use by teenagers is their perception of risk to themselves by smoking marijuana [1]. The perceived risk can be any combination of physical, social, or punitive consequences. This particular factor has been tracked by the “Monitoring the Future” study for many years and shows a clear inverse relationship between use and perception of “great risk” in using regularly [1](figure 1). In the 1970s, when little was known of the risks of use and youth perception of self-risk was almost nonexistent, use was rampant. In the 1980s and very early 1990s when teens’ perception of risk increased significantly secondary to increased scientific evidence of harm with repeated use, coupled with a combined effort by parents, schools, community, and government; the use of marijuana by teens steadily decreased. Starting in the early to mid-1990s, the perception of risk with using marijuana began to decrease, and marijuana use by youth began to increase again to a peak in the late 1990s. Over the past 5 years, the cycle has again begun to reverse, and use has trended downward. The reasons for this latest downward trend are not fully understood. However, the observation that it has not decreased as significantly as in the 1980s is felt by many to be due in part to the fact that the national and local debate over marijuana as a “medicine” and its legalization has not been lost on our young people’s perception of diminished risk with using [22].
Conversely, protective factors which mitigate against use of marijuana by adolescents include strong family relationships, responsible role models, high academic expectations by both the teen and his/her parents, involvement in extracurricular activities, sober peers, close parental supervision, and religious faith [3,4,6,12].

Adolescent Development
Adolescence is synonymous with change. It is the period of one’s life when an individual changes physiologically, emotionally, socially, and academically from a child in a protected environment to an independently functioning adult. It is a time to learn how to deal with success and failure, praise and rejection, happiness and disappointment, frustration and confrontation. It is a time to make choices and deal with the consequences of those choices while still in a semi-controlled and semi-protected environment. Traditionally, this time frame was believed to start at approximately 12 years of age and to be completed by 18 years of age. In the past several years, there has been considerable discussion that this time frame has broadened, with the onset beginning at 8-10 years of age and extending into one’s 20s, especially for the emotional and social developmental components.
Thus, any substance which, with repeated use, impacts or negatively interferes with this developmental trajectory is very serious cause for concern. If one turns to the use of marijuana to avoid or blunt the negative experiences or to try to enhance the positive experiences of adolescence, he/she never learns these lessons and the coping mechanisms necessary to successfully manage them [17,18]. He/she emerges from this critical developmental period as an “adult adolescent.” Furthermore, it is extremely difficult, and for many it is impossible, to go back as an adult and relearn those crucial lessons and skills.

Consequences of Use
Marijuana is not an innocuous drug, and adolescents are not fully mature adults. Effects which are minimal or undetectable in mature adults may have an increased or different impact on an adolescent. Also, effects which might manifest over long periods of time and with repeated use, such as genetic and reproductive effects and cancer-associated effects, may only appear many years later.

Repeated marijuana use has been associated with significant adverse effects on many organ systems [2,4,5,7,18]. The extent to which this impact occurs depends on factors such as potency of delta-9 THC in each use, the method of consumption, the chronicity of use, the effects of the over 400 non-delta 9 THC chemicals found in the crude marijuana plant, and the presence of adulterating substances.

The issue of potency of the delta-9 THC in marijuana is extremely important and deserves special mention [2,18]. Improved technology has resulted in the production of much more potent marijuana over the past 25 years. In the 1970s, the average potency of marijuana was less than 1% THC. By the late 1990s, the average was 3.5-4% THC with some varieties, such as sinsemilla, being between 6-10% or more. The impact of recurrent use of this much more potent marijuana on adolescent users can be very significant and very worrisome.

Acute Effects [2,3,4,5,18,23]
The acute effects of marijuana intoxication may last as long as 12 to 24 hours after use and can be divided into the rapid uptake, or accumulation, phase and the slow release elimination phase. The onset of the rapid uptake phase during which the delta-9 THC is entering the brain during active use may begin within 15 to 30 minutes after initiation of use. Its effects include euphoria, conjunctival injection, elevated blood pressure, tachycardia, tachypnea, initial bronchial dilatation followed later by bronchial constriction, and decreased intraocular pressure. This phase usually lasts 1 to 3 hours after cessation of use. It is then followed by a slow release elimination phase during which the delta-9 THC is slowly released from the fatty tissue of the brain and other organs. In this elimination phase, which can last 12 to 24 hours after use, effects include drowsiness, calmness, increased appetite, irritation and dryness of the nose and throat, hypotonia, tremors, and, most importantly, impaired reaction time.
These effects are transient and usually not deleterious to an otherwise healthy adolescent. However, if the teen has known or undiagnosed underlying medical, psychological, or psychiatric problems, these acute effects can be of significant consequence and can occur or persist for hours after the euphoria has subsided. In addition, these effects are dose-related and affected by both potency and frequency of use. When marijuana is used in moderate to large doses, patients may have significantly impaired motor function and reduced reaction times, decreased speech fluency, impaired short term memory, inability to perform complex tasks, acute panic attacks, anxiety attacks, psychotic episodes, hallucinations, and delusions. These effects can be difficult to distinguish from many psychiatric disturbances. In addition, through its effects on coordination, cognition, reaction time, and decision-making, marijuana use contributes to injuries and accidental deaths in adolescents, especially in motor vehicle accidents. Plus, its effects on judgment and decision making often contribute to an increase in other risk-taking behaviors such as unprotected sexual activity, unintended teen pregnancy, and other drug use.

Chronic Effects [2,3,4,5,18,23]
Delta-9 THC is very lipophilic, and repeated use of marijuana results in accumulation of delta-9 THC in the brain and other fatty tissues of the body. Because it is slowly released from these adipose tissue sites, a reservoir of cannabinoids exists which is replenished with repeated use. In fact, with a use pattern of 1 to 2 times per week or more, the reservoir is constantly renewed, and it will take 4 to 6 weeks or often longer to dissipate once use has completely stopped. Thus, repeated marijuana use impacts the brain, the lungs, the cardiovascular system, the immune system, the endocrine system and puberty, and pregnancy and the fetus and newborn.

The impact of repeated marijuana use on brain function resulting in behavioral and cognitive effects is well known, and the consequences on the not-yet-fully mature brain of the adolescent are even more concerning. While there are varying results of studies of chronic marijuana use and permanent cognitive dysfunction in adults who have stopped using one or more years prior to participation in these studies, there is no disagreement about the significant negative effects on learning, short term memory, and attention span of adolescents who are under the influence of frequent/repeated marijuana use. In addition, a syndrome known by the terms “amotivational syndrome” or “chronic cannabis syndrome” has been reported in chronic heavy marijuana users. This syndrome has been characterized by cognitive impairment, the inability to sustain attention, and a reduced ability to establish or maintain goal-directed thinking and behaviors, resulting in underachievement in the attainment of jobs that require less challenge and technical acuity. In adolescents, this can manifest as an A or B student being content with merely passing grades or dropping out of or not caring about extracurricular activities with which the teen was previously very involved.

Furthermore, there is increasing evidence that marijuana use increases the risk of developing schizophrenia, anxiety, and depression. However, it is as yet unclear whether marijuana actually causes psychiatric illness in individuals who would not otherwise be predisposed, or whether it simply triggers the onset of conditions in those who have a genetic or other predisposition.

Recurrent and chronic smoking of marijuana results in an increased risk of development of chronic lung disease. This increased risk is a result of several factors compared to tobacco smoking. First, the method of inhalation delivers almost twice as much smoke as from a tobacco cigarette. Second, the depth of inspiration and breath holding time is significantly longer with marijuana. Third, marijuana joints have no filter and deliver 50% more carcinogens and 400% more tars and increase blood carboxyhemaglobin by up to five-fold. The increased mucus production, irritation, and bronchospasm produced by recurrent use may thus result in increased chronic and recurrent respiratory symptoms. The relationship of chronic marijuana smoking to respiratory tract concerns including lung cancer has not been fully determined. In light of what is known about tobacco, it is fair to assume that adolescent chronic marijuana smokers are probably at increased risk, especially since they are starting at such an early age. In addition, the theoretical potential increased risk for oral and nasopharyngeal cancers is currently unknown.
Immunologic function may be affected by repeated and chronic marijuana use. Components of marijuana influence the immune system and affect the anti-tumor activities of the body. Marijuana receptors have been found in T and B lymphocytes and macrophages, suggesting an ability for immunosuppression by delta-9 THC. Although increased rates of infection have not been reported among marijuana users, the incremental impact on patients with recurrent respiratory infection cannot be discounted.
Puberty represents a particularly vulnerable period for an adolescent, and recurrent marijuana use may be especially dangerous during this time. Chronic use has been reported to be associated with decreased sperm mobility, decreased sperm counts, decreased circulating testosterone levels, decreased libido, gynecomastia in males, and irregular ovulation, irregular menses, and galactorrhea in females, as well as decreased pituitary gonadotropin levels. Although the exact implications and long-term consequences of the findings are not completely understood, anything that may affect or interfere with the orderly pubertal development and sexual reproductive function is very troubling.

Marijuana is also the most commonly used illicit substance during pregnancy, and teen pregnancy is a significant societal problem. Infants born to mothers who smoked marijuana during pregnancy have significantly smaller lengths, weights, and head circumferences. In addition, metabolites of marijuana cross the placenta and are also found in breast milk. One study of toddlers who were exposed to prenatal marijuana showed alterations in the language skills of those toddlers and, by four years of age, showed pronounced differences in memory and verbal ability. Although the implications of these findings await further study, anything that can impact the brain during the most rapidly developing period of one’s life is cause for very serious concern.
Finally, marijuana use by youth cannot be considered in isolation. While some adolescents will use once or infrequently and stop and some will continue with repeated use but not with other substances, a significant proportion of adolescents will use marijuana as a “gateway” or precursor to the use of other drugs. The reasons for this are multifactoral and include the seeking of a more intense or sustaining mind-altering experience, the relationship of marijuana use with other risk-taking behaviors, the alteration of judgment with repeated use and while under the influence, and the association with drug-using peers. Although the use of marijuana does not necessarily predict progression to the use of additional drugs, one study showed that adolescents who use marijuana are 104 times more likely to use cocaine than are teens who never used marijuana.

Diagnosis
The signs and symptoms of acute intoxication and recurrent and chronic marijuana use have been discussed above. It is important to note that these signs and symptoms often overlap with the signs and symptoms of other drugs of abuse including alcohol use. For an adolescent, the most important aspect of initial diagnosis is not so much which drug is being used but the recognition that the adolescent is in fact using. Often there is more than one drug involved by the time the teen’s symptoms become recognized as a result of drug use.

There are many excellent publications on the principles and elements of evaluating adolescents for substance abuse, and a detailed discussion of this area is beyond the scope of this publication [3,4,7,8,13,16,19]. However, a few general comments are noteworthy. When dealing with adolescents, it is most often successful to gather the information in a nonjudgmental fashion and become more focused as the history-gathering process proceeds. However, once the information has been obtained, it is certainly appropriate as a health care provider to give an opinion or judgment on the adolescent’s health and behavior and the consequences of continued use. Do not forget to acknowledge and compliment the non-user on his/her decision to not use.
Because many health care providers and others feel uncomfortable or less skilled in interviewing teens, especially in this sensitive area, the use of screening questionnaires has become popular. One such brief office instrument is the CRAFFT questionnaire which has been validated and field tested [19]. It consists of six questions with any two or more positive answers being an indication for a more comprehensive assessment or referral for such.

Another area of diagnostic importance is the nontraditional presentations of adolescent marijuana use. These are especially important for those specialists, subspecialists, and emergency room physicians who might not have the experience or comfort with adolescents who are using marijuana and other drugs. Examples of some of these presentations include the adolescent who presents with such symptoms as recurrent fatigue, headaches, weight loss, abdominal pain, lethargy, school absenteeism, symptoms of ADD appearing after age 11 or 12, depression, or other psychological symptoms, such as anxiety or panic attacks. Other more common nontraditional presentations include symptoms of chronic or recurrent mononucleosis syndrome in spite of negative laboratory studies and chronic or recurrent asthma, bronchitis, sinusitis, pharyngitis, and particularly uvulitis, especially when unresponsive to conventional treatment or to treatment that has been successful in the past. One should also consider marijuana use in the evaluation of trauma, especially recurrent trauma, and trauma involving motor vehicle accidents, including bicycles, skateboards, and scooters. Lastly, one must always be aware that an adolescent’s symptoms may not be the result of that teen’s use of marijuana or other drugs, but is presenting as the index case and may be the result of another sibling’s or family member’s use with the resultant chaos and turmoil within the family [7,12]. This is frequently the situation when a younger sibling presents with nonspecific and functional symptoms, such as recurrent abdominal pain, headaches, depression, sleep disorders, or escalating out-of-control behavior.

Laboratory
Once the diagnosis of marijuana use is suspected or confirmed by history, the next consideration is the role of the laboratory, or more specifically, urine testing. In general, the role of the laboratory in the evaluation of marijuana use is the same as its role in the evaluation of all other medical conditions. First, it can be used to confirm information obtained from the history and/or physical examination. Second, it can be used to help explain signs or symptoms which cannot be clearly explained from the history or physical exam. Thirdly, it can be used to assess abstinence as a component of a treatment program.

Initially, a positive clinical history for marijuana use may obviate the need for further laboratory testing, unless there is suspicion of the concomitant use of other drugs. Although hair, blood, saliva, stool, and meconium may be used for testing, urine is the most commonly tested body fluid for marijuana.

In considering the use of urine testing in the evaluation of marijuana use, there are several critical factors of which one must be aware in order to correctly interpret the results. There are several excellent in-depth discussions of these issues including an American Academy of Pediatrics policy statement with an addendum/update soon to be published (personal communication), but some items deserve special consideration [3,4,9,15]. First is the issue of consent and confidentiality. Except for situations such as the inability of the patient to provide consent by virtue of age, maturity, or impaired mental status or judgment, urine testing should be done with the consent of the patient, and with assurances of confidentiality whenever possible [14]. Second, the source of the specimen must be known and procedures to insure that contamination, dilution, substitution, or other acts, whether purposeful or accidental, intended to alter the specimen do not occur. Third, knowledge of the pharmaco-kinetics and elimination profile of marijuana and of the temporal relationships of frequency of use and time of last use to the time of obtaining the specimen is important. Fourth, it is necessary to know the capability of the particular laboratory to identify marijuana and its metabolites, as well as which tests it uses and the sensitivity and specificity of these tests. This is especially important because most laboratories use a cutoff level of 50 or 100 nanograms. If the actual amount of marijuana metabolites is below that amount, the laboratory will report as “none detected,” resulting in a false negative from a clinical standpoint. Fifth, awareness of all of the factors which might result in a false positive or false negative result is essential to the correct interpretation of the results. Lastly, all positives must be confirmed by the more precise gas chromatography/mass spectrometry (GC/MS) technology.

While most health care professionals can agree on the use of urine testing in the evaluation and management of the individual adolescent, there is currently significant debate about the use of laboratory testing as a component of a comprehensive program to prevent adolescents from using marijuana and other drugs. Much of this discussion centers around the distinction between the terms “screening” and “testing” for marijuana and other drugs of abuse. Although many health care professionals use the term “drug screen” when they order a urine test for a panel of drugs of abuse including marijuana, the term “screening” applies to the evaluation of large populations regardless of clinical status, while the term “testing” refers to the evaluation of a single individual on the basis of clinical information or suspicion.

Although there are some preliminary studies and anecdotal reports which state that urine screening for marijuana and other drugs as a component of a comprehensive prevention program done in a non-punitive manner with attention to confidentiality does result in a decrease in marijuana use by adolescents, much more research is needed before any final judgments can be made. One of the problems with the available studies is that they include all students in a given grade or school, without regard to their marijuana or other drug use history, and compare them to themselves in a later year after screening was instituted or to students in another school. These studies do not differentiate the possible impact of such screening programs on the prevention of marijuana use in that population which has never or rarely used versus that population of adolescents who are already recurrent or frequent users. Thus, it remains to be shown, but would be of considerable importance, whether urine screening is an effective prevention component in either or both groups.

Treatment and Management
The management of an adolescent using marijuana will depend on many factors, all of which have goals of abstinence and completion of the developmental trajectory leading to a rewarding, fulfilling, and productive adult life. Because repeated marijuana use not only results in physiological and behavioral consequences but also interferes with the developmental process of adolescence, the management should include not only the individual but also the family, the school, peers, and the community [12]. Both the American Academy of Pediatrics and the American Society of Addiction Medicine have published a treatment recommendation protocol referred to as the “adolescent crosswalk” in which treatment recommendations are based on several factors at the time of assessment and diagnosis [20,21]. The factors center on the impact of the adolescent’s use on his/her daily function [10,17,20,21]. It may take the form of office counseling and abstinence contracts with random urine testing to ensure compliance with the contract or may require a more intense and structured program of outpatient or even inpatient care followed by progressive reintroduction into family, school, and peer and community life. This is often a long term process which can severely stress financial, insurance, and emotional resources of the families.

Summary
Marijuana is a crude plant with over 400 chemical components. It is not an innocuous drug. The seriousness of the behavioral, emotional, and physiologic consequences is sufficient for all health care professionals, family members, school personnel, politicians, and others to recommend strongly against any use of marijuana by young people. These recommendations should be based on the known impact of marijuana use on the brain, including memory, learning, judgment, and possible psychiatric disease, as well as on the lung, the immune system, the endocrine and hormonal systems, trauma associated with acute intoxication, teratogenic potential, interference with motivation and the developmental processes of adolescence, and the known consequences of long-term use.

A discussion of marijuana and other drug use, including family use and attitudes, should be part of the routine periodic assessment of all preteens and adolescents. This assessment may be facilitated by the use of brief office screening tools such as the CRAFFT. Awareness of the adolescent’s marijuana use as having broader family implications is essential.

The use of the laboratory and specifically urine testing should be guided by the principle that it is an adjunct to the evaluation and management of an individual who may be using marijuana and/or other drugs. It should be used with a knowledge of its benefits and limitations and, in general, with attention to confidentiality and patient consent. The role of urine screening for marijuana and other drugs as a part of a comprehensive substance abuse prevention program awaits further studies before wide implementation can be recommended. A key factor may be the impact on prevention in the non-using or rarely-using adolescents as compared to the recurrent and frequent users.

Referral and treatment should be directed to both the adolescent and the family. The level of care should be determined by the impact of the adolescent’s use on him/herself and their family.

References
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Appendix

Figure 1. Marijuana Trends in Annual Use and Risk [1]
USE: % using once or more in the past year	RISK: % saying great risk of harm in regular use

TABLE 1. CRAFFT: Questions to Identify Adolescents With Substance Abuse Problems [19]

Two or more "yes" answers suggest that the adolescent may have a serious problem with substance abuse, and additional assessment is warranted.