Motor vehicle (MV) accidents are the leading cause of death for 15- to 19-year-olds in the United States; they are responsible for 1 in 3 deaths in this age group.^[1] Two of 3 teen fatalities are young men.^[1] Although 15- to 20-year-olds comprise only 6.4% of all licensed US drivers, they are responsible for 19% of annual MV deaths.^[2] Because of their immaturity, young drivers take more risks (eg, speeding). Because of their inexperience, they tend to underestimate driving risks and overestimate their abilities to respond to dangerous situations.^[3,4] Among all novice drivers, the 6 factors most associated with high rates of MV crashes are impulsivity, inattention, poor judgment, distractions, aggression, and impaired executive function skills.^[5-7] It should not be surprising, therefore, that young drivers with attention-deficit/hyperactivity disorder (ADHD) appear to be over-represented in the MV crash and fatality statistics. This is attributed to the twin threats of being a novice driver and having 1 or more ADHD-related traits that increase crash risk (Table 1).

Table 1. Factors Associated With High Rates of Motor Vehicle Crashes

Note: immaturity and inexperience that increase driving risks for all young adult drivers are compounded by additional risks associated with ADHD symptoms, leading to poorer driving outcomes among those with ADHD

Prospective and retrospective studies, drawn both from community samples^[8,9] and clinic-based patients,^[10-14] have documented that, compared with their peers without ADHD, young drivers with ADHD have:

• 2-4 times the risk for an MV accident when driving;
• 3 times the risk of having an accident with physical injury;
• 4 times the risk of being at fault in an accident;
• 6-8 times the incidence of a past driver's license suspension.^[15]

Similar driving problems and histories also have been documented in older adult patients with ADHD.^[16] In fact, 1 recent study indicated that the simulated driving performance of sober, unmedicated adults with ADHD was impaired to a similar degree as alcohol-intoxicated adults without ADHD.^[17]

Because of these higher rates of accidents, injuries, and fatalities, promoting safe driving among youth with ADHD is a public safety concern for us all. Sharing with patients and parents information about the additional risks to young drivers with ADHD may save lives. Each family will need to decide whether to impose supplementary driving rules or prolonged driving restrictions, in addition to the restrictions each state requires of its novice drivers. The clinician's advice is important because maintaining and enforcing unpopular parental rules over time can be challenging. Parents also should be reminded that they must model the driving behaviors they expect from their adolescents (eg, wearing seatbelts).

Discussions about safe driving behaviors should begin well before the adolescent with ADHD reaches driving age, should include parents, and should continue at most patient visits throughout young adulthood. The following recommendations can introduce young drivers with ADHD and their parents to several strategies that may mitigate some of their driving risks.

Medication-Related Recommendations

Drivers With ADHD Should Never Get Behind the Wheel Unless They Have Taken Their ADHD Medication

To date, stimulant medication is the only therapeutic intervention for patients with ADHD that has demonstrated the clear ability to improve driving performance. Eleven studies of almost 250 adolescents and adults with ADHD have shown consistent improvements in both simulator and on-road driving performance and fewer unsafe driving-related behaviors after subjects take stimulants (mostly methylphenidate [MPH]), compared with placebo.^[15,18-23]

A meta-analysis of these studies indicated that the improvements had moderate to very large effect sizes.^[24] Recently, a report of routine, on-road driving of 2 young adults with ADHD (with constant, in-vehicle monitoring) documented that both made fewer driving errors during 2 months of regular osmotic release oral system (OROS) MPH use, compared with 2 months of driving while taking no medication.^[18]

Prospective drivers who are not currently taking medication for ADHD may want to reconsider this option before beginning to drive. Careful titration of stimulant medication to the patient's optimal dose (preferably to full symptom remission) is important for reducing impairments to the greatest extent possible.^[25] In addition, it is crucial that the prescribing physician attend carefully to minimize medication side effects and maximize medication schedule convenience, especially for those who have discontinued or declined to take medication in the past.

Choose Extended-Release Medications Over Shorter-Acting Preparations

Extended-release stimulants. Both extended-release OROS-MPH and extended-release mixed amphetamine salts (MAS-XR) have been associated with improved on-road and simulator driving, especially after 5 PM.^[19] These improvements have been demonstrated unequivocally with OROS-MPH, even when compared with immediate-release MPH (IR-MPH) given 3 times daily.^[26] Sustained, safer driving has been documented as long as 15-17 hours after taking a morning dose of OROS-MPH.^[19]

Moreover, OROS-MPH repeatedly has been shown to foster better adherence to a stimulant medication regimen than IR-MPH.^[27-30] Adherence to treatment is crucially important for young drivers with ADHD because they must be willing to take their medication regularly for it to be effective. With once-daily dosing, extended-release stimulants can reduce ADHD-related driving errors for many hours without the need for reminders or additional efforts from the young driver.

Only a few small studies of MAS-XR have been published (total N < 75 subjects). Results have been less consistent, but they suggest improved driving for as long as 12-15 hours post-dose.^[19,23] Better driving results were observed when adults with ADHD were treated with higher doses of MAS-XR (50 mg vs 30 mg in earlier studies).^[19,23,31] No assessments of other extended-release stimulant formulations have been published.

The data indicating that stimulants appear to improve driving safety among patients with ADHD are so persuasive that in 2006, the Canadian Medical Association's guidelines on medical fitness to drive included this statement:

"Stimulants most likely reduce the risk of moving violations and crashes for drivers with ADHD...long-acting stimulants, which provide medication coverage throughout both the day and night, will likely reduce driving risk in this population."^[32]

For those patients taking morning doses of stimulant formulations that last < 12 hours, an additional dose of medication later in the day may be prudent for patients with ADHD who must drive in the late afternoon or at night (although no studies have evaluated this formally).

Extended-release nonstimulants. The impact of atomoxetine on drivers with ADHD is unclear because only 2 small studies of atomoxetine (total n = 25) have been published to date.^[23,33] Both studies assessed driving after only 3 weeks of atomoxetine treatment, even though the full therapeutic effects of this medication may not be seen until patients have been treated daily for 8-12 weeks.^[34] Additional studies with atomoxetine should assess its effects on drivers with ADHD after longer drug exposures.

Recently, an extended-release formulation of guanfacine (an alpha-2 adrenergic agonist) received US Food and Drug Administration (FDA) approval for treatment of ADHD. An extended-release formulation of another alpha-2 agonist, clonidine, awaits FDA approval.^[35] Future studies will be needed to determine whether these improve driving safety among youth with ADHD.

Discuss Daily Medication Use as a Strategy for Mitigating the Risk for Motor Vehicle Crashes and Fatalities at any Time of Day, Throughout the Year

Many adolescents and their parents think that stimulant treatment for ADHD need only be taken Monday through Friday, 8 AM - 3 PM, when school is in session. These patients often discontinue their medications on weekends, vacations, and during summer months. In reality, however, ADHD typically causes impairments in many nonacademic situations, including driving.^[36] Importantly, the peak times for MV fatalities in young drivers coincide with times when many adolescents with ADHD (and, sometimes, their parents) think that they do not need to be taking stimulant medication:

• 56% of teenage crash deaths occur on Friday, Saturday, or Sunday;
• 50% of teen fatalities occur between 3 PM and midnight;
• 27% of these deaths take place during June, July, or August.^[1]

Every driving experience demands the novice operator's best attention and judgment; anything less substantially increases accident, injury, and fatality risks. We need to share these compelling statistics with our patients and their families, and explain that, for young drivers with ADHD, inconsistent medication adherence may be dangerous. Prescribing physicians should counsel young drivers with ADHD that if they want to drive on any day they wish, during afternoons, evenings, weekends, or summer months, taking long-acting stimulant medication 365 days per year may be appropriate. In fact, some parents and physicians may think that adherence to a daily medication regimen should be a prerequisite for permitting an adolescent with ADHD to drive.

Non-Medical Recommendations

Encourage Families to Negotiate and Sign a Parent-Teen Driving Contract

The Parent-Teen Driving Contract provides parents and their teens a structured way to create a list of required rules and behaviors (the "house rules") that the teen will observe when driving; these requirements must be agreed upon before the teen receives parental permission to drive (see links in Family Resources section). The driving contract also should state in advance the consequences for single and multiple violations of any of these rules, which usually will include loss of driving privileges for specific periods of time, depending on the seriousness of the infraction (Table 2). Parents and teens formally sign this written agreement, after careful discussion. This can be helpful not only as a statement of parental expectations, but also as documentation of the adolescent's pledge to follow the rules and abide by the consequences of rule violations. The contract can be modified as young drivers demonstrate more maturity and trustworthiness.

Table 2. Some Typical Rules in Parent-Teen Driving Contracts

Parents should be encouraged to review several parent-teen driving contracts and add or modify these requirements as appropriate for their families. These rules may be modified as teen drivers demonstrate additional responsibility and maturity. Additional, more severe restrictions may be listed if any violation occurs more than once.

Include Strict Rules to Minimize Distractions in the Parent-Teen Driving Contract

Almost 80% of all recorded MV crashes and 65% of near-crashes involve the driver's looking away from the road in front of his car during the 3 seconds before the event.^[37] So, for young drivers with ADHD, with their underlying vulnerability to inattention, even seemingly trivial in-car distractions amplify their risks for accident, injury, and/or fatality to unacceptable levels. Novice drivers with ADHD should be taught about these dangers, and be required to avoid specific distractions as a condition of parental permission to drive.

Teenage passengers. In 2008, 63% of teen passenger deaths occurred when the vehicle was driven by another adolescent.^[1] The presence of 16- to 25-year-old passengers (especially males) in the vehicle with a teen driver increases the fatality risk to 8 times the national average.^[38] Parents should consider continuing the "no passengers" restriction until they feel confident that their child has both adequate driving experience and good enough judgment to drive safely and responsibly, despite passengers.^[39]

Cell phones and other wireless electronic devices. Among all age groups, 16- to 25-year-old drivers have the highest rates of electronic device use (mostly cell phones) while driving. Yet, a recent study found that the use of hand-held devices was associated with the highest rates of distraction-related near-collisions and MV crashes.^[37] Many people believe that using a hands-free device will make the cell phone safe to use while driving. However, studies have shown that even with a "hands-free" device, conversing by phone is much less safe than driving in a distraction-free setting or having a live conversation with a passenger in the vehicle.^[40-43] Even more dangerous, texting while driving is reported by 43% of 18- to 24-year-old drivers.^[44] The only safe way to send a text message or converse on a cell phone while driving is to pull over to the side of the road and stop the car.

Other hazardous distractions. After teen passengers and cell phone use, the most common distractions posing dangers for drivers are eating, drinking, grooming, adjusting the vehicle's radio/using the CD player, and looking at (or reaching for) objects in the car.^[37] Young drivers with ADHD should understand why these risky (but seemingly innocuous) behaviors must be prohibited during driving. The underlying principle should be that the driver must keep both hands on the steering wheel and both eyes on the road at all times. This rule should be observed indefinitely.

Support Strict Graduated Licensure Programs, and Advise Parents to Consider Extending Restrictions for Several Additional Months for Many Adolescent Drivers With ADHD

As of 2010, all 50 states and the District of Columbia have laws that mandate some form of Graduated Driving License (GDL). GDLs work by delaying the novice driver's permission to drive in situations that pose the highest risk (eg, nighttime driving and driving with teenage passengers) until the teen is older and has more driving experience. Overall, GDL programs have reduced the youngest drivers' crash risk by roughly 20% to 40%.^[45]

Typically, a learner's permit restricts the teen's initial driving experience to driving during daylight hours, and only with a licensed, adult driver sitting beside the novice driver. Then, an intermediate level of licensure may prohibit the novice driver from driving with teenage passengers in the car, and may continue some level of restriction on nighttime driving. However, these restrictions vary greatly from one state to another. For those who wish to compare their state's rules with others, the Insurance Institute for Highway Safety has compiled a list of GDL driving restrictions by state, with safety ratings of their minimum requirements.^[46]

It is important to explain to parents and adolescents with ADHD that the GDL provides only minimal restriction levels, those needed by a typical teen driver. Because teens with ADHD are likely to have more problems mastering the art of driving safely, parents may need to consider extending restrictions on driving at night and driving with teen passengers (and perhaps other restrictions) until they think that the adolescent has demonstrated the maturity and responsibility to manage fewer driving restrictions safely.

Advise Teens That They Should Never Drive Aggressively or When They Are Angry

After an argument with a parent or friend, an adolescent with ADHD may feel that storming off and going for a drive is an attractive way for them to "cool off." However, both adults with ADHD and college students with many ADHD symptoms have reported more aggression and reactive anger while driving than comparison subjects without ADHD.^[47,48]

Recently, Barkley hypothesized that "deficient emotional self-regulation (DESR)" should be added to the classic triad of inattention, impulsivity, and hyperactivity, as a core diagnostic component of ADHD.^[49] He cites low frustration tolerance, impatience, and quickness to anger among signs of DESR that may adversely affect driving behaviors.^[49] Drivers with ADHD need to be taught that aggressive driving is dangerous. Increased awareness of DESR, and conscious modulation of anger and irritability should be discussed frequently during driver training and beyond. Youth with ADHD will need to stay aware of their reactions and work to stay calm while driving, no matter what other drivers do.

Parents Need to Remain Vigilant and Involved in the Supervision of Young Drivers With ADHD

Research demonstrates that risky driving among teens is diminished when there are^[50]:

Clear parental rules and expectations for safe driving practices; eg, observing speed limits, 100% seatbelt use, no cell phone use or eating while driving, abstinence from alcohol and recreational drugs, careful adherence to curfews, no teen passengers;

• Clearly defined and consistently imposed consequences for violating any of the rules;
• Extended parental restrictions, as warranted (especially restricted driving at night and no driving with teen passengers) until parents are certain that their teen's skills and maturity make additional privileges prudent and safe and, finally;
• Ongoing parental monitoring of safe driving (does young driver ask permission, comply with curfew, let parents know her itinerary and when she will return?).

Families should engage in frequent conversations about parental expectations and the driver's own experiences while driving. Some organizations also recommend strongly that parents consider the purchase and installation of an electronic monitoring device in the vehicle.

If the Adolescent Demonstrates Risky Driving, Reduce Driving Privileges

Many teen driving fatalities are preceded by earlier episodes of unsafe driving. Among 15- to 20-year-old drivers involved in fatal crashes in 2007, 13% had previously sustained a crash that was reported to police; 17% had received a previous moving violation or other risky citation; and over 20% had been cited previously for speeding.^[51] Thirty-one percent of teens who were killed in MV crashes during 2007 had been drinking alcohol.^[51] In 2008, 39% of male drivers, ages 15-24 years, who were involved in fatal MV crashes were speeding when the crash occurred.^[52,53] Among drivers younger than age 21 and 21-24 years old who were involved in speeding-associated crash fatalities, 27% and 50%, respectively, also had blood alcohol concentrations of .08 g/dL or higher.^[52.53] Teen drivers and passengers are among the least likely to buckle their seat belts; in 2006, 58% of teen passengers killed in MV crashes were not wearing seatbelts at the time of the crash.^[52,53] Revoking driving privileges after unsafe driving is a matter of safety, not just a disciplinary measure.

Driving Must Remain a Privilege, Not an Entitlement, For Young Drivers

Beginning to drive is a symbol of a teen's increased independence, a recognition of maturity, and a rite of passage in the journey from adolescence to adulthood. Yet, parents still must use their experience and best judgment to decide what is safe for their teenager because the risks can be great. Adults know that it takes years of practice and experience to assess risks and avoid hazardous situations when driving. No parent wants to live with the tragedy of a teen driver having a serious, and possibly fatal, MV accident. Because adolescents with ADHD appear to be at even greater risk for poor driving outcomes than the average teen driver, those with ADHD and their parents must learn about their greater risks and make family decisions accordingly. For teens with ADHD, mastering safe and responsible driving may require more parental supervision and restrictions that last a bit longer. In the end, however, those inconveniences will be worthwhile if they improve driving outcomes for youth with ADHD.

Supported by an independent educational grant from Shire.