Long-Term Consequences of Childhood ADHD and Criminal Activities:
Does childhood mental illness have long term consequences in terms of criminal behavior?

Abstract The question of whether childhood mental illness has long term consequences in terms of criminal behavior has been little studied, yet it could have major consequences for both the individual and society more generally. In this paper, we focus on Attention-Deficit/Hyperactivity Disorder (ADHD), one of the most prevalent mental conditions in school-age children, to examine the long-term effects of childhood mental illness on criminal activities, controlling for a rich set of individual, family, and community level variables. The empirical estimates show that children who experience ADHD symptoms face a substantially increased likelihood of engaging in many types of criminal activities. An included “back-of-the-envelope” calculation of the social costs associated with criminal activities by individuals with childhood ADHD finds the costs to be substantial.

Long-Term Consequences of Childhood ADHD and Criminal Activities:
Does childhood mental illness have long term consequences in terms of criminal behavior?

Introduction Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent and fast growing mental health problems facing children. The prevalence is estimated to be between 2-10% of school aged children, with 7.4 percent of parents who have children between the ages of 3-17 reporting they were told their child had ADHD according to the most recent national survey (Bloom B, 2007). The rate of treatment for ADHD has also increased dramatically over time-from 0.9 per 100 children in 1987 to 3.4 per 100 children in 1997 (Olfson M, 2003). ADHD is more common among boys (10.7 percent) than girls (4 percent) with fewer differences by race. While much research has been documented the short term consequences of ADHD on school-children, such as increased likelihood of pursuing risky behaviors such as smoking (Rattew, 2013) and lower performance (Mannuzza S, 2009), (Fletcher JM, 2008) less research has examined economic outcomes during the transition to adulthood, especially using nationally representative data (Mannuzza S, 2009). This paper contributes to the literature by exploring the link between childhood ADHD and subsequent criminal activity, using nationally represent data that collected retrospective childhood ADHD symptoms as well as early adult outcomes. Existing evidence suggests a link between ADHD symptoms and crime but there had been little research using large longitudinal samples of individuals to test this hypothesis. For example, a recent FBI report shows that adolescents with ADHD symptoms had more adversarial contacts with law enforcement agencies than other adolescents (19.3 odds) and are more likely to be in juvenile justice facilities (5:1 odds) (Investigation, 2000) but this study does not include other controls nor does it speak to the commitment of crimes. In addition to examining the longitudinal link between ADHD symptoms and criminal activities, we also advance the literature by analyzing the tie between differing dimensions of ADHD on crime such as inattentive, hyperactive, and combined typologies. The results show that both inattentive and hyperactive symptoms during childhood increase the likelihood of engaging in numerous types of criminal activities-in many cases the increases in risks for negative behaviors associated with ADHD are substantial. However, there is little evidence that individuals with symptoms of the combined type of ADHD face a multiplicative risk. Since existing research (Freeman R, 2000) suggests that total social costs of crime may be as high as 4 percent of gross domestic product with a direct average loss to victims of $500 per crime, crime associated with ADHD could have substantial negative effects on gross domestic product and societal well-being more generally. The empirical findings of this paper suggest a substantial payoff to early interventions that either reduce the incidence of ADHD or reduce the consequences of ADHD for the individuals and hence for society.

Background While much is known about the family and individual level predictors of childhood ADHD, there are still many open questions about its specific causes. Four and a half million children ages 3-17 were reported to have ADHD according to data from the 2006 National Health Interview Study (Bloom B, 2007). ADHD is more likely to occur in males, children in families with low socioeconomic status, and children with parents who have a high school diploma or GED. Prevalence of ADHD is much higher among close relatives than in the general population, suggesting a genetic tie (Biederman J, 2005). Treatments for ADHD still remain somewhat controversial. On one hand, approximately 70% of the patients with ADHD respond to treatment with stimulant medications in the short term and over periods of up to 18 months (Olfson M, 2003). On the other hand, long-term effects of many treatments are unknown (Bussing, 1998). Additionally, pharmacotherapy alone has not yet been shown to improve the long-term outcome for any domain of functioning (Rattew, 2013), and treatment has been found to be less effective in adults (17). While the explosion in pharmacological therapy occurred in 1991, as yet there are no long term studies of the consequences of long term use. The influence of ADHD on children occurs along several dimensions. Children with ADHD have been found to have fewer close friends (Bagwell C, 2001) and exhibit antisocial behavior (Biederman J, 2005), poorer educational outcomes may be the most important economic consequence of ADHD (Fletcher JM, 2008). In particular, ADHD has been tied to poor concentration and impulsiveness during preschool (VA., 1992) (VA., 1992) lower grades and greater retention and suspension (Mannuzza S, 2009) poorer perceptions by teachers (Corrado, 2002) and lower eventual educational attainment (Fletcher JM, 2008). Researchers have also found an increase in risky behaviors, including earlier sexual intercourse and lower rates of contraceptive use (Barkley, 2002). ADHD has also been shown to be linked with several measures of criminal activity, although much of this research has been used small convenience samples of individuals or assessed the relationship in a cross-sectional context. Individuals with ADHD have been shown to be more likely to commit both minor offenses such as traffic violations and speeding (Kupchick, 2008) as well as crimes leading to incarceration (Corrado, 2002). In particular, property theft, carrying a concealed weapon, illegal drug possession, and arrests rates have been shown to be positively related to ADHD status (Mannuzza S, 2009), (Biederman J, 2005), (Barkley, 2002) as have admission into juvenile justice facilities (Root, 2009). However, in most cases the reported associations were estimated using cross sectional data on fewer than 300 individuals. Nevertheless, these studies all suggest there are economic consequences of ADHD in the form of increased crime. In addition to direct consequences of ADHD for individuals, there is evidence that families are also penalized by the illness. From the increase in medical expenses (Root, 2009) of $500 to $1500 per child per year, families with children with ADHD face increased likelihood of disturbances in family and marital functioning (Billups SC, 2005) and worse maternal mental health (Biederman J, 2005). Crimes as adolescents and young adult is also important because it may have long term economic consequences. Billups, Mocan and Overland (Biederman J, 2005) have shown that current criminal involvement increases the probability of future crime by increasing what they term criminal human capital and depreciating “legal” human capital. Bound and Freeman (Billups SC, 2005) and Freeman and Rogers (Freeman R, 2000) have shown a particularly strong link between the commitment of crime and subsequent reduced labor force participation and earnings for black youth. Thus society may face both the direct costs of crime and the cost of lower earnings and productivity from those with ADHD symptoms.
Conceptual Framework The basic model motivating this study stems from Becker’s path-breaking paper (Becker, 1976) extended by Ehrlich (Erhlich, 1991), which argues that participation in criminal activity is the result of individual’s optimizing response to legal and illegal market opportunities. That is, rational economic agents decide to engage in criminal activity after comparing the financial rewards from crime to those obtained from legal work, taking into account the probabilities of apprehension, conviction and the severity of punishment. ADHD symptoms are likely to influence the perceived rewards from both sectors: perhaps most evidently by lowering the perceived rewards from the legal sector and less evidently by lowering the probability of conviction by a belief that ADHD might be used as an excuse for illegal activity. The first pathway linking ADHD and crime (lowering the perceived rewards from the legal sector) is consistent with the negative influence of ADHD on school performance. Children with ADHD symptoms tend to be more likely to repeat a grade, complete fewer grades and do less well in terms of grades. Thus they will tend to have less education. They may also expect that the same factors that reduce their school performance will limit their formal job market opportunities. The second pathway linking ADHD and crime (using ADHD to reduce the probability of conviction) has been attempted, though generally unsuccessfully, in trials (Becker, 1976). The factors that underlie these patterns, especially poor school performance and criminal activities, may be linked to the two sets of symptoms measured here. The first set, inattention, is likely to impede the ability to understand materials presented in the classroom, reduce the knowledge of and completion of homework, lower the performance on tests, and reduce the penalties for engaging in illegal activities. All of these factors predict that the youth with inattention symptoms is likely to be far less successful in school and therefore leave school earlier than otherwise expected. The same symptoms may also inhibit the full understanding of the consequences of numerous actions, including various crimes. This pattern may lead the youth to engage in criminal activities, both because labor market activities are limited and because the full consequences of engaging in such activities are not recognized. Easy crimes such as stealing, using and selling drugs, robbery and even burglary may all occur with little attention paid to consequences.

The second type of ADHD (hyperactive) is generally associated with limited control of impulses or an increase in impulsive behavior. These youth tend to be more disruptive, lose friends and engage in risky behaviors. They too are likely to be less successful in school and in social settings. These youths would seem more likely to engage in crimes that are impulsive and to act in ways that lead to arrest. We expect to see youths with hyperactive symptoms engaging in crimes such as stealing and especially robbery but not selling drugs since this activity requires at least some planning. We also expect them to be more likely to be arrested and convicted of the crimes they do commit. Thus we have clear predictions of differential crimes committed by youth with these two types of ADHD. When we analyze the behavior of youth as a group without differentiation, we expect to see a higher probability of engaging in all of the crimes mentioned above.
Conclusion
The evidence presented above leads to a clear conclusion: persons with symptoms of ADHD during the period 5–12 years of age, whether they be of the hyperactivity, inattentive or combined type, are far more likely to report criminal activities as young adults than other individuals. This clear pattern prevails even while other factors that might be expected to influence risk taking are taken into account; these factors include individual characteristics such as gender, race/ethnicity, education of parents, family income, type of family in which raised, and community characteristics such as poverty and income, race/ethnicity, income inequality, the unemployment rate and crime rates. These results are also consistent with the expectations of economic models of crime: persons with ADHD have lower labor market expectations and so are more likely to commit a crime than our other otherwise similar adolescents and young adults. Turning to results on type of ADHD, the evidence suggests that persons with the inattentive type symptoms are more likely to commit all of the studied crimes except robbery than individuals with no ADHD symptoms. This group was more likely to engage in crimes that might require some planning such as selling drugs or burglary. Individuals with impulsive symptoms had the highest increase in criminal activities of all the ADHD-types and were more likely to be arrested and convicted of a crime. The impulsive nature of their disorder seemed to lead them to engage in more impulsive crimes such as theft and robbery. Interestingly, individuals with the combined-type of ADHD symptoms had the weakest associations with crime; we find very little evidence that these individuals are at a multiplicative risk of criminal activities in comparison with individuals who have only inattentive or only hyperactive symptoms. This result is surprising. Our results are robust across several specification checks, including lowering the ADHD threshold, controlling for additional variables, and using family fixed and random effects specifications. The magnitudes of the random and fixed effects results are largely consistent with the results for the entire sample, but due to the smaller sample size, fewer are statistically significant, especially for the fixed effects estimates which are run over the smallest number of observations. Since the economic model suggests that human capital is the important factor “explaining” gains from legal activity, we also report evidence that ADHD leads to greater participation in crime without controlling for education in our model. That is consistent with other literature that notes a direct effect of ADHD on educational outcomes (Fletcher JM, 2008), (Corrado, 2002). In results, the association between ADHD symptoms and risky behavior outcomes is often 10–20% higher when we do not control for education in our specifications. Clearly then our results provide evidence that there are sizeable economic costs in the form of increased rates of crime for individuals who report symptoms of ADHD as children; costs borne by the individuals, their families, and society more generally. A rough estimate of this cost to victims is between $50 and $170 million dollars per year and our estimate of the total cost to society is between $2 and $4 billion dollars per year; a very sizeable cost to society. This evidence suggests that children showing ADHD symptoms should be viewed as a group at high risk of poor outcomes as young adults. As such, a good case can be made for targeting intervention programs on this group of children and conducting evaluations to learn if such interventions are effective in reducing the probability that these children commit a crime. Development of such intervention programs and evaluating them for efficiency could be dollars well spent in terms of crime and drug abuse averted. The reader should recall however that a disadvantage of the dataset used here is that we do not know whether the individuals were ever treated for ADHD. As noted above, most of the individuals in this dataset were children before special education services were mandated for individuals with ADHD, which occurred in 1991. If few of the individuals in the data were ever treated for ADHD, then the results above provide an upper bound of the effects of ADHD on longer term life outcomes; now that ADHD is treated at much higher rates than when the individuals in this dataset were children the negative consequences may be far less severe. If most of the individuals with ADHD symptoms in the dataset were treated during childhood, then ADHD would still represent a significant cost to individuals and society in terms of adult outcomes. Of course, the costs of medical care, pharmaceuticals and counseling in treatment of ADHD all must be included in any full account of the costs and consequences of ADHD.

References
Bagwell C, M. B. (2001). Attention-deficit hyperactivity disorder and problems in peer relations. Academy of child Adolescent Psychiatry, 1285-1292.
Barkley, R. (2002). Major life activity and health outcomes associated with ADHD on work performance. Clinical Psychiatry, 10-15.
Becker, G. (1976). Crime and Punishment. Political Economics, 169-217.
Biederman J, F. S. (2005). Attention-deficit hyperactivty disoreder. Lancet Medical Journal, 237-248.
Billups SC, M. H. (2005). A dynamic model of differential human capital and criminal activity. Economica, 655-681.
Bloom B, C. R. (2007). Vital Health Stat. . National Center for Health Statistics, Vol. 10.
Bussing, R. e. (1998). Children in Special Education Programs. American Journal of Public Health, 88.
Corrado, R. (2002). Multi-problem, violent youth. Washington, DC: IOS Press.
Erhlich, I. (1991). Participation in legitimate activties. Theoretical and emperical investigations, 521-565.
Fletcher JM, W. B. (2008). Child mental health and humancapital accumulation. Medical Journal, 27, 794-800.
Freeman R, R. W. (2000). Area economic conditions and the labor market outcomes of young men in the 1990s expansion Inc. New York : Russell Sage Foundation.
Ginaulati, E. (2013). Back to normal. Boston: Beacon Press.
Investigation, F. B. (2000). Crime in the United States. Washington, DC: Uniform Crime Reports.
Kupchick, A. (2008). Juvenile Crimes. New York: LFB Scholarly PUB.
Mannuzza S, K. R. (2009). Long-term prognosis in attention-deficit hyperactivity disorder. Child Adolescent Pyschiatry Clinical Journal, 711-726.
Olfson M, G. M. (2003). National trends in the treatment of attention deficit hyperactivity disorder. Am J Psychiatry, 1071-1077.
Rattew, D. (2013). Child temperment: new thinking about traits and psychological disorders. New York: Nortan & Comapny.
Root, E. (2009). Kids caught in the psychiatric maelstrom. Santa Barbra, California: Praeger.
Stoff D, B. J. (1997). Public health perceptive on interpersonal violence among youths in the United States. New York: Wiley & Sons.
VA., H. (1992). The effects of ADHD on the life of an individual, their family and community from preschool to adult life. Arch of Dis Child, 2-7.