OBJECTIVE: We sought to better understand the trend for prescription attention-deficit/hyperactivity disorder (ADHD) medication abuse by teenagers.
METHODS: We queried the American Association of Poison Control Center's National Poison Data System for the years of 1998–2005 for all cases involving people aged 13 to 19 years, for which the reason was intentional abuse or intentional misuse and the substance was a prescription medication used for ADHD treatment. For trend comparison, we sought data on the total number of exposures. In addition, we used teen and preteen ADHD medication sales data from IMS Health's National Disease and Therapeutic Index database to compare poison center call trends with likely availability.
RESULTS: Calls related to teenaged victims of prescription ADHD medication abuse rose 76%, which is faster than calls for victims of substance abuse generally and teen substance abuse. The annual rate of total and teen exposures was unchanged. Over the 8 years, estimated prescriptions for teenagers and preteenagers increased 133% for amphetamine products, 52% for methylphenidate products, and 80% for both together. Reports of exposure to methylphenidate fell from 78% to 30%, whereas methylphenidate as a percentage of ADHD prescriptions decreased from 66% to 56%. Substance-related abuse calls per million adolescent prescriptions rose 140%.
CONCLUSIONS: The sharp increase, out of proportion to other poison center calls, suggests a rising problem with teen ADHD stimulant medication abuse. Case severity increased over time. Sales data of ADHD medications suggest that the use and call-volume increase reflects availability, but the increase disproportionately involves amphetamines.
Attention-deficit/hyperactivity disorder (ADHD) affects between 8% and 12% of children and 4% of adults worldwide.1–3 The most frequently prescribed stimulant ADHD medications include mixed amphetamine salts and methylphenidate. Recently, there has been a significant increase in the diagnosis of ADHD and the use of prescription stimulants.4–8 In the early 1990s, the prescription rate for methylphenidate tripled.5,9,10 Several reports using different doses of methylphenidate demonstrated tolerance, sensitization, and withdrawal, suggesting the properties eliciting dependence and the potential for abuse.11,12 Although the majority of individuals with ADHD use their medications appropriately,13 increased prescriptions will likely lead to increases in medical adverse effects associated with the use of medications and potentially greater use of these drugs for nonmedical purposes.14
The Office of National Drug Control Policy and the National Institute on Drug Abuse15,16 found that, next to marijuana, prescription medications are the most common drugs that teenagers use to get high. Teenagers are abusing prescription drugs because of their belief in their safety and for reasons beyond getting high, including relief of pain or anxiety, aid with sleep, experimentation, help with concentration, or to increase alertness.17,18 A Partnership for a Drug-Free America survey showed that nearly 1 in 5 (19%) teenagers reported abusing prescription medications that were not prescribed to them at least once.19 According to the National Survey on Drug Use and Health, 9% of adolescents aged 12 to 17 years used prescription drugs for nonmedical purposes in the past year, including 2% who admitted to nonmedical use of stimulant medication. In 2004, the rates of emergency department (ED) visits for patients aged 12 to 17 years were 3.3 visits per 100000 population for methylphenidate (1.7 for nonmedical use) and 4 visits per 100000 population for amphetamine-dextroamphetamine (2.8 for nonmedical use).20
Abused prescription medications most often belong to the adolescents themselves or a friend.21 In 2003, ∼20% of girls and 13% of boys reported borrowing or sharing prescribed medication.22 In 2001, Poulin23 found that adolescents' reported nonmedical use of prescription stimulants correlated with the number of prescription users who reported giving away their medication. In addition, nearly 30% of adolescents report having a friend that abuses prescription stimulants.16
It is clear that there is a significant supply of ADHD medication available to adolescents, but little is known about adolescent abuse and diversion of these medications. We sought additional information on adolescent abuse and diversion and how the usage has changed over time.
The American Association of Poison Control Centers (AAPCC) maintains the National Poison Data System (NPDS), a data set of uniformly collected data on every human exposure call to a member center. The NPDS was initiated in 1983 and includes over 41.1 million cases through 2005. Over 2 million new cases are reported annually.24,25 Because cases are managed by specialists in poison information (health care professionals with specialized training in clinical toxicology), they are uploaded to the NPDS. Patient identifiers are not transmitted from the individual poison center to the national database. Categories of information include patient and caller demographics, the exposure scenario, the substance(s), symptoms and signs of clinical toxicity, treatment, and medical outcome. Criteria for each type of entry are standardized nationally, and poison specialists are tested to ensure that these criteria are used for all data entries. However, because the data are based almost exclusively on telephone contact, the clinical data can vary in detail and accuracy.
The NPDS was queried to find cases of adolescent prescription ADHD medication exposure meeting the following criteria: human, 13 to 19 years of age, and reason is intentional abuse or intentional misuse. ADHD medications were determined by using substance codes. All ingested substances are documented in the NPDS by using 7-digit codes provided in a product identification and poisoning management database (POISONDEX [Thomson Micromedex, Greenwood Village, CO]). All product codes (generic and branded) for stimulant ADHD medication were identified and used in the search. The stimulant medications were categorized as (1) amphetamine and/or dextroamphetamine or (2) methylphenidate (including d-methylphenidate). Other amphetamine-related drug codes were excluded, for example, illicit amphetamine and methamphetamine codes and prescription amphetamines used for weight loss.
Additional case data retrieved included the medical outcome, gender, caller site, and site of the exposure. The medical outcomes are categorized by poison center protocol as no effect, minor effect (minimally bothersome and usually resolve rapidly), moderate effect (more pronounced, more prolonged, or of a systemic nature), major effect (life-threatening or resulted in a significant residual disability or disfigurement), and death by using standardized definitions. Exposure and call sites include home, other residence, school, hospital, and other. The AAPCC defines misuse as improper or incorrect use of a substance and abuse as the improper or incorrect use of a substance where the victim was likely attempting to gain a high, euphoric effect or some other psychotropic effect. Diversion is the use of prescription drugs for recreational purposes.
To contextualize any change in ADHD medication exposure calls, the baseline trend in poison center use was analyzed for the 8-year period. Specifically, the total number of human exposure calls, total population served by the 61 regional poison center members of the AAPCC, the total number of all calls coded as intentional abuse, the subset of these with codes for ages 13 to 19 years, and the total number of acetaminophen product exposures coded as suicide (both all ages and teenagers aged 13–19 years) were reviewed.
To understand the impact of changes in sales and market share over the period, we sought office-based physician recommendation data on these ADHD stimulant products by using data from IMS Health, Inc, of Plymouth Meeting, Pennsylvania. Their National Disease and Therapeutic Index database is derived from an ongoing survey using quarterly sampling from a panel of >4000 representative physicians who record all drug uses (recommendations for prescription and over the counter medications) for 2 assigned, consecutive work days per quarter. Mathematical extrapolations were made from this sample to estimate the annual recommendations made by all office-based physicians in the continental United States. This index estimates the annual number of recommendations for every generic and branded medication by specific indication (International Classification of Diseases, Ninth Revision codes), gender, and age group. This data set was used to determine the amount of pharmaceutical prescription stimulants recommended for ADHD treatment of adolescents (10–19 years old) and preadolescents (3–9 years old) from 1998 to 2005. Prescriptions to teenagers and preteenagers were used as a proxy measure for medications in the home available to teenagers. The National Disease and Therapeutic Index uses the term “drug uses” for mentions of a drug in association with a diagnosis during an office-based patient visit. It is important to note that drug use does not necessarily result in a prescription being generated.
The general linear models using least squares regression analysis (SAS 9.1 [SAS Institute, Inc, Cary, NC]) was used to analyze trends.
Approval for data use was obtained from the AAPCC Data Access Committee and the board of directors. Data were provided to the investigators in a coded fashion to maintain blinding to the individuals and poison centers. The study was also reviewed by the institutional review board at Cincinnati Children's Hospital Medical Center and deemed exempt.
Over the 8-year period, calls related to adolescent abuse of prescription ADHD medication rose 76% from 330 to 581 per year. During this same time period prescriptions of these medications written to 10- to 19-year-olds rose 86% from 4.2 million to 7.8 million and those for 3- to 19-year-olds increased 80% from 6.5 million to 11.8 million (Table 1). The increase in total calls related to teen ADHD abuse and the increase in ADHD prescriptions is not significantly different.
The 76% rise in the number of calls for teen abuse of ADHD medications is significant and is faster than the also significant rise in the number of calls for victims of substance abuse generally (59%) and teen substance abuse specifically (55%). For comparison, during the same period, the annual rate of total and teen exposures as well as total and teen acetaminophen suicidal exposures was unchanged. This demonstrates a significant independent rise in reports of adolescent abuse of ADHD medication.
Within the ADHD stimulant medication category, amphetamine/dextroamphetamine-related calls increased 476% from 71 to 409 (P = .0003) per year, whereas prescriptions for amphetamine/dextroamphetamine increased 133% from 2.2 million to 5.2 million (P = .0004) for 3- to 19-year-olds and 141% from 1.5 million to 3.6 million (P = <.0001) for 10- to 19-year-olds. The number of teen amphetamine/dextroamphetamine abuse calls per million prescriptions of amphetamine/dextroamphetamine to 10- to 19-year-olds increased 140% from 48 in 1998 to 115 in 2005 (P = .005). Methylphenidate-related calls decreased 30% from 246 to 172 annually (P = .003), whereas prescriptions for methylphenidate increased 52% from 4.3 million to 6.6 million (P = .0038) for 3- to 19-year-olds and 57% from 2.7 million to 4.3 million (P = .0019) for 10- to 19-year-olds. The number of teen methylphenidate abuse calls per million prescriptions of methylphenidate to 10- to 19-year-olds decreased 55% from 91 in 1998 to 40.5 in 2005 (P = .0001). In this context it is interesting to note that reports of exposure to methylphenidate (as a percentage of teen ADHD medication-related abuse calls) fell from 78% to 30% (P = .0004). The percentage of prescriptions of the methamphetamine subgroup (as a percentage of total stimulant prescriptions) decreased from 66% to 56% for 3- to 19-year-olds and from 65% to 54% for 10- to 19-year-olds, but neither was statistically significant.
Final outcome was determined in 64% of these calls (some were lost to follow-up or followed until likely outcome). Overall, 42% of these adolescents experienced moderate effects, major effects, or death. The proportion of these clinically significant cases rose over time from 30% to 43%. Moderate effects, major effects, and death were significantly more frequent in amphetamine/dextroamphetamine reports compared with methylphenidate reports (45% vs 37%; P < .001). The difference in severity between methylphenidate and amphetamine/dextroamphetamine did not change over time (P = .804). Interestingly, reports of more severe ingestion effects were more frequent in boys (girls: 3 deaths, 9 major effects; boys: 1 death, 49 major effects).
The percentage of calls related to girls increased significantly over the period from 36% to 42%, or 0.65% per year (P = .032). Of note, girls' reported symptoms were less frequently classified as a severe (major or death) than boys. Girls represent 40.1% of all victims but only 19.4% of major effects or death.
Most cases (79%) were ultimately managed at or referred to a health care facility. The majority of calls were related to exposure at home (67%). Seventeen percent of exposures occurred at school, but only 5% of the calls originated at school.
The sharp increase out of proportion to other poison center calls and general poison center use suggests a rising problem with abuse, teen abuse, and particularly teen ADHD stimulant medication abuse. It may be that abuse is rising, or it may be that increased calls are a result of the escalating severity, perhaps reflecting the shift toward amphetamine use.
Amphetamine exposures rose faster than amphetamine sales. In contrast, methylphenidate calls fell as sales rose. Amphetamine exposures were more frequently classified as moderate to severe than methylphenidate exposures (45% vs 37%). The difference in severity between methylphenidate and amphetamines did not change through the years. The fact that patients with amphetamine use are slightly sicker may account for a small increase in percent of calls originating from hospitals. More likely there is a shift toward amphetamine abuse with greater availability of this medication.
The frequency of reported ingestion by girls is similar to the 2006 National Electronic Injury Surveillance System data that suggested that 42% of ADHD stimulant ingestion cases that present to EDs are girls.14 However in epidemiologic settings, the ratio of diagnosed boys to girls with ADHD is only 3:1 (25% girls).26
As expected, the majority of the ingestions occurred at home. Noting the difference between site of abuse and site of call as the school, it is likely that in some cases the original call came to the poison center from the hospital, after the school sent the child to the hospital without calling the poison center. In other cases, symptom onset may have been at home, after school.
Most calls regarding the abuse of ADHD stimulant drugs involved an ED at some point in the patient's course. The rise in all calls because of abuse and specifically those because of teenaged abuse suggests that EDs may be experiencing workflow issues related to a rise in abuse. Because many teen abuse-related ED visits are managed without involvement of the poison center, the demonstrated rise in poison center calls for abuse cases suggests increased patient volume experienced by EDs.
Although, there are less than 1000 calls annually, and these numbers can be subject to bias, these data are broad, consistent, and representative. Moreover, total poison center use is stable (all calls and acetaminophen suicide calls). There is no general secular trend in use of poison centers. Other poison center calls, including all abuse and all teen abuse, have increased, but not to the extent of teen ADHD stimulant abuse.
The NPDS is a unique source of surveillance data regarding toxic exposures in the United States and is continuously updated in near real-time. Because calls are initiated by the general public, health care professionals, and emergency responders, the data collected may provide a broad description of exposures. Many of the exposures do not result in toxicity, providing a more accurate perspective of the prevalence of toxicity after exposures to various substances compared with databases that only include patients who present for health care treatment. Reporting to poison centers is passive and is often initiated in response to the caller's need for additional information. Reporting is not required or regulated. As a result, the NPDS underreports poisonings in general and in particular substance abuse and poisoning fatalities.27,28 Previous studies have also shown that treatment/referral thresholds vary among poison centers and that this variability influences health care facility use patterns.29 Because data are collected during telephone consultations, data accuracy and completeness cannot be independently verified. The data collected cannot provide incidence data or the absolute value of the change in use by the teenaged population, but instead, trends that are thought to be occurring in this age group.
Although we have found an increase in both the prescription and the abuse of stimulant medication, it is important to note that previous studies show that prescription of stimulants for ADHD does not lead to drug abuse/addiction by the patient.30,31 In fact, therapy with stimulant medications for ADHD is associated with a reduction in the risk for subsequent substance use disorders.32 Furthermore, our data do not suggest that abuse is “kindled” by availability, merely that it occurs and has grown. Twenty to thirty percent of adults presenting with substance use disorders also have concomitant ADHD,33,34 and 20% to 40% of adults with ADHD have a previous history of substance use disorders.35 Patients tend to receive a diagnosis of ADHD earlier than one of substance use disorder.36
The sharp increase in calls related to teen ADHD stimulant medication abuse, out of proportion to other poison center calls, suggests a rising problem with abuse of these medications. Case severity increased over time. Call-volume increases (76%) parallel sales increases (80%), but the percentage of calls related to amphetamines (22% to 70%) is rising faster than sales.
Funding for the acquisition of IMS Health National Disease and Therapeutic Index prescription data was graciously supplied by the RADARS System, a governmental nonprofit operation of the Rocky Mountain Poison and Drug Center, an agency of Denver Health and Hospital Authority.
- Accepted March 17, 2009.
- Address correspondence to Jennifer Setlik, MD, Cincinnati Children's Hospital Medical Center, Emergency Medicine, ML 2008, 3333 Burnet Ave, Cincinnati, OH 45229. E-mail:
The AAPCC (www.aapcc.org) maintains the national database of information logged by the country's 61 poison control centers. Case records in this database are from self-reported calls: they reflect only information provided when the public or health care professionals report an actual or potential exposure to a substance (eg, an ingestion, inhalation, or topical exposure, etc) or request information/educational materials. Exposures do not necessarily represent a poisoning or overdose. The AAPCC is not able to completely verify the accuracy of every report made to member centers. Additional exposures may go unreported to poison control centers, and data referenced from the AAPCC should not be construed to represent the complete incidence of national exposures to any substance(s). The authors' opinions do not necessarily represent those of the AAPCC or its member centers.
Financial Disclosure: The authors have indicated they have no financial relationships relevant to this article to disclose.
What's Known on This Subject:
There are significant challenges facing pediatricians who treat patients with ADHD. Pediatricians need to know the increasing impact of abuse of medications used to treat ADHD and how this relates to the increase in prescriptions of these medications.
What This Study Adds:
We reviewed national poison center information and demonstrate the significant increase in calls regarding abuse of ADHD medications. Moreover, this information was compared with the increased prescriptions of these medications.
- ↵Safer DJ, Zito JM, Fine EM. Increased methylphenidate usage for attention deficit disorder in the 1990s. Pediatrics.1996;98 (6 pt 1):1084– 1088
- Cox ER, Motheral BR, Henderson RR, Mager D. Geographic variation in the prevalence of stimulant medication use among children 5 to 14 years old: results from a commercially insured US sample. Pediatrics.2003;111 (2):237– 243
- ↵Califano JA. Under the Counter: The Diversion and Abuse of Controlled Prescription Drugs in the US. New York, NY: National Center on Addiction and Substance Abuse, Columbia University; 2005
- ↵Johnston LD, Bachman JG, Schulenberg JE. Monitoring the Future: National Results on Adolescent Drug Use: Overview of Key Findings. Bethesda, MD: National Institute on Drug Abuse; 2005
- ↵Office of National Drug Control Policy, Executive Office of the President. Teens and prescription drugs: an analysis of recent trends on the emerging drug threat. Available at: www.the-antidrug.com/pdfs/TEENS_AND_PRESCRIPTION_DRUGS.pdf. Accessed February 1, 2008
- ↵Boyd CJ, McCabe SE, Cranford JA, Young A. Adolescents' motivations to abuse prescription medications. Pediatrics.2006;118 (6):2472– 2480
- ↵Partnership for a Drug-Free America. The Partnership Attitude Tracking Study (PATS): teens in grades 7 through 12. Available at: www.drugfree.org/Portal/DrugIssue/Research/Teens_2005/Key_Findings_On_Teen_Drug_Abuse. Accessed July 23, 2009
- ↵Novak SABJ. Emergency department visits involving ADHD stimulant medications. In: The New Dawn Report. Washington, DC: Substance Abuse and Mental Health Services Administration; 2006
- ↵Poulin C. Medical and nonmedical stimulant use among adolescents: from sanctioned to unsanctioned use. CMAJ.2001;165 (8):1039– 1044
- ↵Jensen PS. Epidemiologic research on ADHD: what we know and what we need to learn. ADHD: a public health perspective conference. Attention deficit hyperactivity disorder: a public health perspective, sponsored by CDC, National Center for Environmental Health, and the Department of Education, Office of Special Education Programs, Atlanta, GA, September 23–24, 1999
- ↵Centers for Disease Control and Prevention. Attention-Deficit Hyperactivity Disorder (ADHD). Available at: www.cdc.gov/ncbddd/adhd/. Accessed July 23, 2009
- ↵Wilens TE, Faraone SV, Biederman J, Gunawardene S. Does stimulant therapy of attention-deficit/hyperactivity disorder beget later substance abuse? A meta-analytic review of the literature. Pediatrics. 2003;111 (1):179– 185
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