Trends in adolescent substance abuse have shown a decline in rates of use of many substances, yet adolescent drug use remains a serious problem. Addressing this problem requires an understanding of the causes and extent of the issue. Counseling families on protective factors helps prevent problems from developing in at-risk youth. Laboratory methods may be of further benefit either to delineate the type of drug abuse or to provide further confidence that specific drugs are not being abused.
Two ongoing surveys that evaluate current use and trends in adolescent substance abuse are the Youth Risk Behavior Survey (YRBS)1 and the Monitoring the Futures (MTF) study2 (Table 1, see page 958). Both surveys have shown that overall use of illicit drugs has declined since the 1990s, while trends for individual substances are less encouraging. Tobacco and alcohol remain the most common substances used by adolescents. The rate of decline for tobacco use has slowed significantly, and alcohol use, binge drinking, and driving while drinking remain major problems in adolescents.
In 2004, rates for eighth, tenth, and twelfth graders admitting to drinking alcohol in the prior 30 days were 19%,35%, and 48%, respectively.2TheYRBS found a binge drinking rate of 28.3% overall,1 while the MTF has shown a slight increase in high school seniors for 2004.2 YRBS data show that 12.1% of adolescents have driven a vehicle after drinking in the 30 days prior, and 30.2% have ridden in a car with someone who has been drinking.1 Alcohol -related motor vehicle accidents are the number one cause of mortality in the 15 to 24 age group.1
Marijuana remains the most common illicit drug of abuse. Ecstasy, or MDMA (3,4 methyl enedioxymethamphetamine), hit its peak in 2001 but has been showing a decline since that time as the perceived amount of risk has risen sharply. Heroin use has remained steady since 2001. The availability of more purified forms of heroin, allowing for greater highs through noninjectable routes of administration (such as snorting), has contributed to its continued popularity.3 The use of prescription narcotics (eg, codeine, hydrocodone, oxycodone, propoxyphene) has shown an increasing trend over the 1990s, with rates continuing to show small increases through 2004. Inhalant use has shown a gradual decline since the mid-1990s, with this drop starting to reverse in 2003, showing that use may again be on the rise. Younger adolescents more commonly abuse inhalants, with the peak annual use seen in eighth grade students. Use of anabolic steroids has increased significantly over the last 15 years. Most disturbing is that the highest rates are seen among younger and female students (7.3% in female ninth grade students).1'2 The perception of widespread use among professional athletes likely has contributed to this ongoing dilemma.
Recognizing the manifestations of the common drugs of abuse can help focus screening questions and testing. The most common illicit drug, marijuana or tetrahydrocannabinol (THC), causes impaired short-term memory, euphoria, distorted time perceptions, lowered inhibitions, and increased appetite. Physical manifestations include red eyes, tachycardia, dry mouth, sluggish pupils (initially dilated), and sleepiness. Regular users exhibit cognitive and memory deficits, anxiety, and chronic cough even when they are not "high." Another longterm effect can be an amotivational syndrome, in which users lose interest in most aspects of life outside the drug use. A physiologic dependence with physical withdrawal symptoms of irritability, sleeplessness, and depressive symptoms has been well documented, but because of the storage of the drug within the body, it generally is only seen in heavy users who stop abruptly, such as when admitted to treatment facilities.4
Drug Use in Adolescents
The use of stimulants such as amphetamines, methamphetamines, and cocaine presents as a hyperalert, talkative, agitated state with elation and euphoria early and irritability, aggressiveness, anxiety, paranoia, and insomnia later. Physical signs include dilated pupils, elevated temperature, sweating, tachycardia and arrhythmias, hypertension, nausea, dry mouth, tremor, and hyperactive reflexes.
The term "opiates" refers to naturally occurring alkaloids derived from the poppy, which include heroin, morphine, and codeine. The term "opioids" refers to all agents that bind to opioid receptors, to include many prescription pain relievers. Users experience euphoria, delirium, anesthesia, and sedation. Physical signs include pinpoint pupils, decreased respiratory and heart rate, vasodilation with flushing and lowered blood pressure, drowsiness, and constipation. Heroin abusers experience more pronounced effects, although a sufficient dose of any opioid can cause similar symptoms.5 Abuse of prescription opioids, including the long-acting form of oxycodone, has been on the rise.
Hallucinogens include lysergic acid diethylamide (LSD) and the "club drugs" MDMA,gamma-hydroxybutyrate(GHB), and ketamine. Effects include euphoria, depressed mood, and visual and auditory illusions or hallucinations. MDMA, an amphetamine derivative, causes an enhanced sense of well-being and a feeling of closeness with others. Physical signs of LSD and ketamine use include dilated pupils, tachycardia, elevated blood pressure, elevated temperature, and diarrhea. MDMA causes similar symptoms, with muscle hypertonicity (especially jaw muscles) and the possibility of severe hyperthermia with diaphoresis. GHB has more depressant effects, with bradycardia and respiratory depression.6
An issue that is unique to adolescent drug use in teenagers is that their central nervous systems are still maturing, and the neurotoxic effects of some drugs may have prolonged negative consequences by interfering with normal growth and development.7
Why do adolescents use drugs? There is no single answer, but multiple risk factors contribute to the problem. They use drugs when they are available, when they perceive a benefit, and when they recognize no reason to avoid them. Adolescents who abuse drugs do so because of other problems in their lives, which put them at increased risk or leave them looking for an escape.5'8
All of these risk factors can be addressed, and providers should assess them and provide appropriate parental education where needed. Decreasing drug availability is an important intervention for parents. Paying attention to with whom the teen spends time and decreasing unsupervised time have been shown to be effective. Providing information about drugs is proven to affect trends in drug use. The MTF study has shown consistently that when the perceived risk of any given drug rises, the use soon declines, and that the inverse is also true. Mass media seems to be one of the most effective tools. The 2002 antiecstasy (MDMA) campaign by the Partnership for a Drug-Free America, working with the Office of National Drug Control Policy, contributed significantly to changing the pervasive public opinion of MDMA being a "benign" substance with little risk.2 One-time interventions consistently have been proven to have little long-term benefit, so it is important that ongoing reinforcement be part of any anti-drug program.
Another helpful method for protecting adolescents from drug use is increasing their level of involvement with family, school, clubs, sports, church groups, and organizations outside of school. However, these are only effective if there is a sense of attachment and belonging to these groups. All parents can endeavor to increase that sense of connection and involvement in their teen's life. Parenting style is another factor that has proven to be very significant, and an area where parental education can be beneficial. Both permissive ("do whatever you want") and authoritarian ("do it because I said so!") parenting styles have been shown to put adolescents at increased risk. An authoritative style of parenting, which sets firm rules with consequences but encourages discussion and a supportive environment, repeatedly has been proven to be the most protective for multiple high-risk behaviors.8
As the statistics show, the majority of teens have some experiences with drug experimentation, and screening the adolescent during routine health care visits is important. Several screening tools have been developed, including HEADS,9 CRAFFT,10 and POSIT.11 Offering the adolescent a confidential, nonjudgmental setting and having an open discussion often reveals a considerable amount of information. Laboratory tests should not be relied upon as the sole source of information, as there are important limitations to the tests that are available.
Characteristics of Common Laboratory Methodologies Used for Drug Testing
When physicians think of "screening," usually a test or method that can be used to exclude a diagnosis is being considered. Paradoxically, drug "screening" is not truly a good method for "ruling out" drug abuse or use. The testing methods commonly available worldwide do not reliably exclude drug use. The timing of most recent drug use, chronicity of drug use, method of testing, sample tested, and drugs "screened" for affect the ability of the laboratory to detect drugs within the sample. The quality of the laboratory performing the tests also can influence the accuracy and predictive value of the drug screening.
For example, a laboratory with excellent comprehensive drug screening might have 98% sensitivity and specificity, while a laboratory with a lesser quality drug screen might have 80% sensitivity and 95% specificity. This decrement in quality may lead to a significant increase in false-positive screening tests, as well as a decreased negative predictive value of the testing. Thus, the authors believe that the use of laboratory testing for drug abuse in adolescents, if done, should be carried out in conjunction with other nonlaboratory screening methods and with a full understanding of the limitations of the tests that are being used.
MAJOR TESTING METHODS
Several commonly employed methods for drug detection are available. These have highly variable sensitivity, specificity, cost, and ease of performance (Table 2). Commonly employed "drug of abuse screens" found in most hospital emergency rooms usually employ immunoassay methodology for a small group of analytes or drugs. This panel of drugs assayed usually consists of the National Institute for Drug Abuse-5 (NIDA-5) - amphetamines, marijuana, cocaine, opiates, and phencyclidine (PCP) - and other drugs of abuse of specific national or local concern.
A comprehensive drug screen may include many of these methods. For example, the "screen" may use a Spectrochemical test for salicylates, 5 to 8 immunoassays for the common drugs of abuse, thin-layer chromatography (TLC) for a group of 30 to 50 drugs and prescription medications, high-performance liquid chromatography (HPLC), and gas chromatography (GC) and GC/mass spectrometry (GC/MS) for 50 to 70 compounds. Schools, sports organizations, and monitoring bodies may use an array of testing methods ranging from the simplest spot tests to complex use of GC/MS to detect drugs in the human body.
Testing Characteristics of Common Drugs
Immunoassays are the most commonly employed methods of drug detection in the toxicology laboratory and in drug of abuse screens. This method is able to detect low concentrations of substances with a high degree of specificity through the use of antibodies. Various methods of immunoassay have been developed, including Enzyme Multiplied Immunoassay Technique, Fluorescence Polarization Immunoassay, Kinetic Interaction of Microparticles in Solution, and Cloned Enzyme Donor Immunoassay. All immunoassay methods rely on drug-specific antibody to either bind free drug or to bind a drug "labeled" by some means such as with fluorescein or enzyme linking with glucose-6-phosphate dehydrogenase.
Spot tests are point of care tests that usually can be performed at the bedside. These are very simple tests that rely on the rapid reaction of a drug with a reagent This reaction generally produces a color change in the result area of the detection device. In the past, this type of testing was popular. With the advent of cheap and reliable immunoassays, spot tests have become uncommon for use as screening techniques for drug use or abuse.
Like spot tests, Spectrochemical tests rely on a chemical reaction between an agent and the drug to form a light-absorbing substance that can be detected. These tests are better controlled than spot tests and light is measured at specific wavelengths, often using a spectrophotometer to measure the colored product produced in the reaction quantitatively. While Spectrochemical tests have better sensitivity and specificity than spot tests (Table 2), they are seldom used to detect drugs of abuse in toxicology screens.12
TLC and HPLC
TLC involves the movement of a control specimen and a patient specimen on a plate coated with a thin layer of silica gel. TLC may be unable to detect low levels of drugs and therefore may not be a good technique to detect potent drugs such as LSD.13 HPLC uses high pressures and smaller particle sizes to allow better resolution of the chromatogram in a smaller period of time. TLC provides qualitative information at a relatively low cost, while HPLC allows detection of low levels of compounds quickly but at a higher cost. HPLC often is employed for drug level determination when an immunoassay is not available (Table 2).
An Approach to Drug Testing Results in the Office Setting
GC and GC/MS
GC is analogous to HPLC except that the moving phase of the separation is a gas, usually helium. This technique is useful for detecting a wide range of substances and, like HPLC, can provide quantitative measurement as well. The use of the mass spectrometer as the GC detector allows a very high level of sensitivity and specificity in the analysis of the sample. The downside of this technique is that it is very labor intensive and the most expensive of the major analytical techniques.
Many body substances are good sources for detecting drugs of abuse. While urine continues to be the most commonly tested, hair, sweat, breath, and blood are all sometimes used.
Urine is universally available, easily collected, and easily handled in the laboratory. However, it is a common target of adulteration via dilution, substitution, or chemical additives. Blood provides the highest level of correlation with actual recent drug use of all body substances, but collection techniques are invasive.
Recently, there has been much interest in the use of hair for drug detection. Various labs advertise their techniques as reliable, sensitive, and specific; however, concern over environmental contamination remains the major concern with use of hair. Easy to collect, hair enables the testing for substance use over a prolonged period of time.
Breath testing theoretically could be used to detect many volatile substances, but in practice it is used only for ethanol. Sweat testing is an evolving technique that involves placing a tamper-proof patch on the skin for 1 week. This allows detection of substance use over a prolonged period of time in a noninvasive manner. Salivary tests are evolving and hold promise for detection of a variety of drugs of abuse such as THC.
When a decision is made to perform drug testing within an organization, the leadership of the organization must focus on a particular set of drugs. It is not realistic for the organization to run comprehensive drug tests using all aforementioned techniques on each employee, student, or athlete. Multiple studies clearly demonstrate a link between positive drug tests and absenteeism, disciplinary actions, and workplace injuries.14'15 The decision to carry out testing must attempt to balance worker rights with the rights of the employer and should use epidemiological data and the input of counselors to guide these decisions.
A list of testing characteristics of common drugs is provided in Table 3 (see page 960). Organizations that have decided to conduct drug testing usually choose a handful of drugs to include on their panel. These usually include the NIDA-5. Cocaine, amphetamines, marijuana, phencyclidine (PCP), and opiates are the only drugs tested according to Department of Transportation regulations, which apply to agencies such as the Federal Aviation Administration, Federal Transit Administration, and the U.S. Coast Guard.16 Testing for other drugs may be reasonable but usually depends on the reason for testing (eg, pre-employment screening, random sampling, monitoring during drug rehabilitation).
Cannabinoids are commonly abused and are illegal under federal law in all 50 states except in the prescription form of dronabinol. People frequently have attempted to ascribe positive cannabinoid tests to passive inhalation. This is extraordinarily unlikely, and illicit use in these circumstances is almost certain. Ingestion of hemp seeds or hemp oil likewise have not been demonstrated to cause positive THC results when used in a manner consistent with all but very extreme circumstances.17
Urine samples usually are analyzed using the immunoassay technique. Common detection times are 1 to 2 days for single use and up to 3 to 4 weeks for chronic use.
Cocaine is a very common drug of abuse. There are no legitimate reasons for a true positive test except for topical drug application in a medical setting (eg, the use of cocaine for otolaryngologic procedures). Detection time is 2 to 3 days.
Like cocaine, amphetamines are abused frequently. In the past, over-thecounter medicines such as pseudoephedrine were frequent causes of false-positive amphetamine immunoassays. Newer immunoassays result in fewer false-positive tests and additionally often are able to detect some of the designer, mood-modifying amphetamines, such as MDMA.18
Abuse of heroin has long been common in the US, and current detection via immunoassay usually focuses upon detection of heroin, codeine, morphine and metabolites. Heroin is metabolized to 6-acetylmorphine (6-AM), which has a half-life of about 30 minutes. 6-AM is metabolized to morphine. Codeine is metabolized to three major primary metabolites, one of which is also morphine. Morphine's half-life is 8 hours.
Morphine, heroin, or codeine use results in a positive immunoassay for opiates. However, GC/MS or confirmatory tests showing 6-AM confirm heroin use. Findings of higher ratios (greater than 3: 1 ) of morphine to codeine or high levels of morphine without codeine make morphine or heroin use likely.
The wide variety of foods containing poppy seeds has led to true false-positive opiate tests. These do not cause positive tests more than 48 hours after consumption, however.19 It is also important to note that the other opioids, such as hydrocodone, fentanyl, oxycodone, methadone, meperidine, and propoxyphene, do not cause positive opiate immunoassays. If these drugs are suspected, tests for these must be specifically ordered.
PCP is included in the NIDA-5 drugs, although by most reports its use in the US is infrequent A handful of common overthe-counter medicines may cause false positive tests, including dextromethorphan and diphenhydramine, mandating confirmation testing with GC/MS.
Ethanol is the most widely abused drug in the United States. Breath and blood (GC) are the sources used to assess for ethanol use, as both give quantitative results and prediction of real-time intoxication.
GHB testing can be done on urine at a handful of laboratories in the U.S. Tests have been developed for the detection of GHB in beverages or bodily fluids but are not very specific. Available laboratory testing has primarily used GC/MS. As of this writing, rapid GHB testing is not available readily, and the practitioner should consult the laboratory and regional poison control center for further information when GHB testing is deemed necessary.
Like GHB, ketamine can be detected with various methodologies such as HPLC and GC/MS. These are not widely available as screening methods but can be performed when abuse of these specific drugs is suspected. Laboratory and toxicology consultation is recommended.
Tryptamines, including LSD, N N-dimethyltryptamine (DMT), and psilocybin, are all "testable" but require an index of suspicion by screening personnel and specific direction to the laboratory to guide testing.
Steroid testing in athletes has become a major topic recently in the U.S. Testing for these agents most commonly uses GC/MS and focuses on the 17-alkyl substitution found on anabolic steroids, which is not altered during drug metabolism.20'21 Additionally, demonstration of alkylation of the steroid ring and detection of testosterone ratios (such as the ratio of epitestosterone to testosterone) can help identify exogenous use of steroids. Some oral anabolic steroids have short half-lives and can be used 3 to 4 days prior to testing while longer acting parenteral agents may be detected for 6 months after use.
BEATING THE TESTS
One needs only to go online to discover the plethora of techniques suggested to "beat" the drug testing process. These include dilution, vigorous hydratíon, the use of diuretics, the purchase of artificial urine or prosthetic genitals, and the use of pH-altering substances. Most laboratories that perform drug testing more specifically analyze specimens that they suspect have been adulterated. While some attempts at the use of adulterants to bypass positive tests have been successful, the reaction of a given adulterant with an immunoassay cannot be predicted, and it is possible that an adulterant may lead to recurrent testing if a sample is considered adulterated by the testing laboratory.
Issues of patient trust and confidentiality are important in any treatment program and must be taken into consideration. There is no easy solution to drug abuse in adolescents, and maintaining their trust so that one can continue to work with them is necessary. Testing a patient without his or her knowledge is almost always a bad idea, except during situations in which they cannot give consent, such as acute intoxicatioa Random testing carries a high probability of missing occasional use, or missing drugs of abuse that are not part of the standard testing panel. More useful information is obtained through focused testing after events when use is suspected and discussion with the laboratory about what substances are likely to have been used. Periodic screening during treatment can help ensure abstinence and may give the adolescent the added incentive to avoid drugs.
Information on interpreting drug test results appropriately is provided in Table 4 (see page 961).
Treatment of adolescent substance abusers is difficult. Treatment programs at multiple levels, from inpatient facilities to outpatient support groups, usually are available. Some of the most encouraging results have come from programs that involve family therapy in addition to individual treatment.22 Knowing what resources are available, as well as the referral processes based on a particular patient's healthcare plans, facilitates access and makes dealing with these issues in a busy outpatient setting much easier. Frequent follow-up with an adolescent after a treatment program has been initiated to monitor for compliance and relapse can ensure a better drug-free outcome.
Knowing the extent of the adolescent drug abuse problem should encourage providers to incorporate some type of screening into their routine care of adolescents. None of these methods is 100% sensitive, and incorporating each component into the process where appropriate likely is the best approach. Knowing risk and protective factors for drug use is helpful for both recognition of candidates for screening and counseling of parents regarding drug use prevention.
1. Youth Risk Behavior Surveillance - United States, 2003. Centers for Disease Control and Prevention. MMWR Surveill Summ. 2004: 53(SS-2).
2. Johnston LD, O'Malley PM, Bachman JG, Schulenberg JE. Monitoring the Future national results on adolescent drug use: overview of key findings, 2004. Bethesda, MD: National Institute on Drug Abuse. NIH Publication No. 05-5726.
3. Schwartz RH. Adolescent heroin use: a review. Pediatrics. 1998;102(6): 1461-1466.
4. Schwartz RH. Marijuana: a decade and a half later, still a crude drug with under-appreciated toxicity. Pediatrics. 2002;109(2):284-289.
5. Greydanus DE, Patel DR. Substance abuse in adolescents: a complex conundrum for the clinician. Pediatr Clin North Am. 2003;50(5): 1179-1223.
6. Neinstein LS, Heischober BS. Miscellaneous drugs: stimulants, inhalants, opiates, depressants, and anabolic steroids, hi: Neinstein LS, ed. Adolescent Health Care: A Practical Guide. 4th ed. Philìdelphìa, PA: Lìppìncott, Williams & Wilkins; 2002:1337-1369.
7. Tarter RE. Etiology of adolescent substance abuse: a developmental perspective. Am JAddict. 2002;11(3):171-91.
8. Brown RT. Risk factors for substance abuse in adolescents. Pediatr Clin North Am. 2002;49(2): 247-255, v.
9. Goldenring JM, Rosen DS. Getting into adolescent heads: an essential update. Contemp Pediatr. 2004;21(1):64-90.
10. Knight JR, Shrier LA, Bravender TD, et. al. A new brief screen for adolescent substance abuse. Arch Pediatr Adolesc Med. 1999;153(6):591-596.
11. Latimer WW, O'Brien MS, McDouall J, et. al. Screening for "substance abuse" among school-based youth in Mexico using the Problem Oriented Screening Instrument (POSIT) for Teenagers. Subst Use Misuse. 2004;39(2): 307-329.
12. Osterloh JD. Laboratory diagnoses and drug screening, hi: Haddad LM, Shannon MW, and Winchester JR, eds. Clin ical Management of Poisoning and Drug Overdose. 3rd ed. Philadelphia, PA: WB. Saunders Company; 1998:46-48.
13. Mikkelsen SL, Ash KO. Adulterants causing false negatives in illicit drug testing. Clin Chem. 1988;34(ll):2333-2336.
14. Normand J, Salyards SD, Mahoney JJ. An evaluation of preemployment drug testing. J ApplPsychol. 1990; 75 (6): 629-639.
15. Ryan J, Zwerling C, Jones M The effectiveness of preemployment drug screening in prediction of employment outcome. J Occup Med. 1992;34(11):1057-1063.
16. Procedures for transportation workplace drug and alcohol testing programs. Office of the Secretary, DOT. Final rule. Fed Regist. 2000;65(244): 79462-79579.
17. Leson G, Pless P, Grotenhermen F, Kalant H, ElSohly MA. Evaluating the impact of hemp food consumption on workplace drug tests. J AnalToxicol. 2001;25(8):691-698.
18. Hsu J, Liu C, Liu CP, et al. Performance characteristics of selected immunoassays for preliminary test of 3,4-methylenedìoxymethamphetamine, methamphetamine, and related drugs in urine specimens. J Anal Toxicol. 2003;27(7):471478.
19. Elsohly HN, Elsohly MA, Stanford DF. Poppy seed ingestion and opiates urinalysìs: a closer look. J Anal Toxicol. 1990;14(5):308-310.
20. Kammerer RC. Drug testing and anabolic steroids, hi: Tesalis C, ed. Anabolic Steroids in Sport and Exercise. Champaign IL: Human Kinetics Publishers; 1993:283-308.
21. Wilson JD. Androgen use by athletes. Endocr Rev. 1988;9(2): 18 1-199.
22. Stanton MD, Shadish WR. Outcome, attrition and family-couples treatment for drug abuse: a meta-analysis and review of the controlled, comparative studies. Psychol Bull. 1997;122(2):170-191.
Drug Use in Adolescents
Characteristics of Common Laboratory Methodologies Used for Drug Testing
Testing Characteristics of Common Drugs
An Approach to Drug Testing Results in the Office Setting