In a prior issue of Attention Research Update, I reviewed a study of the association between ADHD symptoms at age 13 and the development of driving difficulties during late adolescence/early adulthood.  Results from this study indicated that, compared to other 13 year-olds, those with high levels of ADHD symptoms were:

-- about 3 times more likely to  be involved in an accident than those with low levels of symptoms;

-- about 2.5 times more likely to report having driven while seriously intoxicated;

-- about 3 times more likely to have been involved in street racing; and,

-- likely to have an overall traffic violation score more than twice as high.

Although these differences were not as pronounced after controlling for other relevant factors (e.g. conduct problems, IQ, family environment factors, driving experience), ADHD symptoms continued to predict the development of driving difficulties -- most importantly, the risk of an auto accident involving injury.  (For a complete description of this study go to: http://www.attention.com/library/articles/article.jsp?id=47&parentCatId=6&ca tegoryId=37. Results from this study were consistent with several other recent reports in which a significant association between ADHD and more problematic driving records has been found.

These results provide an understandable basis for why parents of ADHD adolescents may be particularly concerned as their child begins his or her driving career.  It is thus somewhat surprising that, given the large number of studies in which the effects of stimulant medication have been examined, no studies have examined whether stimulant medication improves the driving performance of individuals with ADHD.  This is an important issue to address, as evidence that medication reduces driving-related risks to individuals with ADHD could have important implications for recommendations about medication usage.  For example, if medication was found to improve the driving performance of individuals with ADHD, parents and physicians might be more insistent that adolescents receive medication during evenings and weekends.  These are times when medication typically may not be administered to teens, but when the bulk of an adolescent's driving is likely to occur.

A study published last year in the Journal of Nervous and Mental Diseases (Cox, D., et al., (2000). Effect of stimulant medication on driving performance of young adults with ADHD: A preliminary double-blind placebo controlled trial. v. 188, 230-234) represents the first effort to document the effects of medication treatment on the driving performance of ADHD individuals.

In this study, 7 young adult males with ADHD and 6 matched comparison subjects (average age was about 22 years) completed two 30-minute driving tests on a sophisticated research-driving simulator.  (The validity of this simulated driving task as an indicator of real world driving performance had been demonstrated in several prior studies.)  Before one of the tests, participants were given a 10 mg dose of Ritalin.  Before the other test, they were given a placebo (i.e. a vitamin C tablet). The order of medication vs. placebo administration was counter balanced across all participants.

The driving scenario used in this investigation was specifically chosen to simulate routine, fairly monotonous driving -- the type of driving conditions in which individuals with ADHD are more likely to demonstrate poorer performance.  After each 30-minute session, participants were asked to rate their performance on a 1 (poor) to 5 (excellent) scale.  Actual performance data related to steering, braking, and crash variables also was available from the computer-based simulation. The sum of these variables was used to create an impaired driving score for each participant.

Results

The design of this study enabled the researchers to examine 3 interrelated questions:

1. Do young adult males with ADHD have poorer driving performance as measured on a computerized driving simulator when compared to matched controls?

2. Does the driving performance of young adult males with ADHD improve with the use of Ritalin?

3. Are individuals with ADHD aware of their relative driving performance?

As expected, in the placebo condition, ADHD participants had significantly higher impaired driving scores than control subjects.  The fact that this difference was statistically significant, given the small number of participants, is striking (i.e. with small samples, it is more difficult to obtain statistically significant results) and speaks to the magnitude of the difference in driving scores between the 2 groups.  In addition, results of simulated driving tests were consistent with the actual driving history of the 2 groups: the ADHD participants had, on average, more than 3 times as many accidents than comparison subjects.

Despite doing significantly worse in the placebo condition, after taking Ritalin the driving performance of the ADHD participants was no different than that of controls. In fact, every single participant with ADHD obtained a lower impaired driving score on medication than he had on placebo.  For the comparison subjects, such improvement was evident in only a single individual.

The participants' ratings of their driving performance parallel the results obtained for the actual driving data.  For ratings obtained in the placebo condition, ADHD participants rated their driving performance significantly lower than comparison subjects.  Ratings obtained for the medication condition did not differ between the groups.

Summary and Implications

This is the first study to provide evidence that stimulant medication -- in this case, Ritalin -- can yield substantial improvements in the driving performance of individuals with ADHD.  As noted above, all 7 participants with ADHD provided evidence of safer driving after taking Ritalin.  Despite the small sample size, and the necessary cautions about generalizing these findings to the larger population of individuals with ADHD (i.e. we do no know whether similar results have been obtained with adolescents, older adults, and females?), these are important results for parents and clinicians to consider.

Clearly, it will be important to replicate this study with a larger and more diverse sample.  In the meantime, these data still have important clinical implications for parents and practitioners to consider.  It is still relatively common practice for individuals with ADHD to follow a dosing regimen in which medication is restricted to those times of the day and/or week where it is felt to be most necessary.  For adolescents, this would typically be the school day, and perhaps a late afternoon dose to assist with homework.  For adults, this would generally be for hours corresponding to their work schedule.  During evenings and weekends, however, when adolescents and adults may do the bulk of their driving, this regimen is unlikely to provide any benefit for their driving safety. Teen-age drivers with ADHD may be especially unlikely to be on medication at those times when the risk of a serious auto accident (i.e. late evenings) is greatest.

Many adolescents are resistant to taking medication period, of course, and these results should definitely NOT be interpreted as indicating that every adolescent driver who takes meds for ADHD should be required to take medication before driving.   In the first place, it is important that this study be replicated with adolescents to be certain that the same findings apply.   Even if this is found to be the case, there is always the need to consider the specifics of each individual's circumstances.  With these important caveats in mind, however, results from this investigation do suggest that, for teens who take medication to treat ADHD, there may be important benefits to their being on medication while driving. This is an issue that parents and health professionals may wish to consider.

Although numerous studies on the treatment of ADHD have been conducted, most have been limited to examining the effectiveness of particular treatments (e.g. medication, behavioral therapy, neurofeedback, dietary interventions, etc.) without regard to how aspects of parents' thinking may impact treatment outcome.  Because parents are ultimately responsible for implementing prescribed treatments, it is possible that how parents think about themselves and their child could influence children's outcomes through the influence these beliefs have on parents' willingness/ability to consistently implement the treatments that have been recommended.

It is not difficult to imagine examples of how this could occur.  Parents who believe their child has no control over non-compliant behavior may feel that imposing limits and consequences is pointless. They may, therefore, be unwilling to comply with recommendations that are part of behavioral treatment.  Similarly, parents who lack confidence in their parenting ability, or who have low self-esteem in general, may find it difficult to enforce consequences or consistently administer medication when faced with resistance from their child.  In other families, parents who believe the problematic behavior of their ADHD child is always deliberate and willful, and are unwilling to consider that ADHD symptoms are a contributing factor, may frequently react with anger and punitive discipline, and be unwilling to implement the kind of parenting strategies that can be more helpful for many children with ADHD.

Despite these reasons for hypothesizing that parents' thinking about their child, themselves, and their parenting may influence children's treatment outcomes, there has been virtually no research conducted on this important topic.  A study published in the December 2000 issue of the Journal of Abnormal Child Psychology (Hoza, B. et al. Parent cognitions as predictors of child treatment response in ADHD, 28, 569-583), however, provides an interesting initial look at this understudied area.

This study was conducted in conjunction with the MTA study, the largest treatment study of ADHD ever conducted.  In the MTA study, 579 6-12 year-old children with the combined type of ADHD were randomly assigned to one of four different treatment conditions -- careful medication management; intensive behavioral treatment, the combination of careful medication management and intensive behavioral treatment; and routine community care.

The current study included 105 children and parents from 2 of the 6 MTA study sites who agreed to participate in an "add-on" investigation to the main study.  These parents completed a number of measures designed to assess their self-esteem, their feelings of parenting efficacy (i.e. how confident they felt about their parenting skills), the adaptiveness of their discipline strategies, and the types of attributions they made about their child's behavior (i.e. did they consistently blame their child's non-compliant behavior problems on lack of effort and/or poor mood as opposed to recognizing that such behavior could also reflect other factors, including the impact of ADHD).

These aspects of parents thinking and disciplinary strategies were collected separately for mothers and fathers prior to any child receiving treatment. Fourteen months later, parent and teacher reports of children's ADHD symptoms and oppositional/defiant behaviors were collected.  The authors could then examine whether parental thinking and disciplinary strategies influenced children's outcome even after treatment benefits had been taken into account. They predicted that regardless of which treatment a child received, the outcome would be better when parents had higher self-esteem, reported more adaptive disciplinary strategies, and held more adaptive attributions about themselves and their child.

Results

For mothers, self-esteem and self-report of dysfunctional discipline both had a significant impact on child outcome.  Across all 4 treatment groups (i.e. medication management, behavioral intervention, combined treatment, and community care) children whose mothers had higher self-esteem and who used fewer dysfunctional disciplinary strategies were doing better (i.e. their parents and teachers reported they were showing fewer ADHD symptoms and less oppositional behavior).

For fathers, the use of fewer dysfunctional disciplinary strategies also predicted more positive outcomes.  In addition, children did better when their fathers were less likely to "blame" their child's non-compliance on lack of effort and/or bad mood.  Finally, there was a strong trend indicating that high parenting efficacy for fathers (i.e. having confidence in one's ability to handle the demands of parenting) predicted more positive child outcomes.

In addition to examining how aspects of parental thinking and disciplinary style related to children's outcomes, it is also interesting to look at the relationship between these variables.  For mothers and fathers, higher self-esteem was associated with a more positive disciplinary style.  And, parents who felt more confident in their parenting ability (i.e. higher parental efficacy scores) were less likely to endorse dysfunctional disciplinary strategies or blame their child's non-compliance on lack of effort.

Summary and Implications

The major findings of this study: parental cognitions and parental reports of dysfunctional disciplinary strategies predicted children's treatment outcomes 14 months later.  It is important to emphasize that these factors had a significant impact on children's outcomes even after all gains associated with treatments received in the MTA study had been taken into account.

For mothers, self-esteem emerged as a significant predictor of child treatment response.  The authors speculate that perhaps mothers with low self-esteem experience doubts about their parenting ability, thus making them prone to engage in dysfunctional disciplinary practices which have a negative affect on child outcome.  Among fathers, those with higher feelings of parental efficacy, and were less prone to blame children's non-compliance on poor effort and/or bad mood, had children who were doing better. The authors suggest that this may occur because feelings of efficacy in fathers encourage more positive involvement with their child and fewer dysfunctional disciplinary practices.

Although the exact mechanisms by which these aspects of parental thinking influence treatment outcome cannot be determined from this study alone, the results provide strong evidence that such factors can play an important role.  The authors argue that, because parents are the implementers of treatment for children with ADHD, parental factors such as those examined here should be considered as possible targets for treatment.  As was demonstrated here, even when children are receiving the most careful medication treatment and/or the most systematic behavioral treatment available, certain aspects of parental thinking can still have an important influence on treatment success.

An encouraging aspect of these results is that they underscore the critical role parents play in the development of children with ADHD.  For parents who question whether they can play an important role in promoting their child's healthy development above and beyond making sure their child takes the right medication, these data clearly indicate they can.  How parents think about themselves, and how confident they feel in their role as parents, may have a meaningful impact on the success of whatever treatment(s) their child is receiving.  This paper will hopefully stimulate additional work in this important area.