Attention Deficit Hyperactivity Disorder: A Mitigation of Criminal Responsibility?

Abstract

Neuroscientific findings have established that brain injury due to trauma (TBI) and brain immaturity of adolescents result in a diminished self-control and therefore are considered mitigations of criminal culpability in forensic settings. This article presents neuroscientific evidence which documents that attention deficit hyperactivity disorder (ADHD) also results in diminished capacity for self-control because of impaired brain functioning. Therefore, it proposes that impaired brain functioning in ADHD should be considered a mitigation by the same logic that impaired brain functioning in TBI and the immature brain functioning in adolescents are considered mitigations. Recommendations for implementing this proposal in forensic practice are presented.

KEYWORDS:

• attention deficit hyperactivity disorder (ADHD)
• culpability
• diminished capacity
• neuroscience

Notes

1. ¹ Note, however, that brain scans that have found differences in brain structure and functioning between groups of individuals with and without ADHD cannot currently be used to diagnose ADHD because the variation among individuals in both groups is too great (Hinshaw & Scheffler, 2014).

2. ² Deficient self-control is probably the single most important variable in explaining developmental origins of antisocial behavior (Moffitt, 2012; Moffitt et al., 2011).

3. ³ Justice Kennedy, in writing for the majority in Roper, also cited two other characteristics of adolescents that mitigated their responsibility for criminal behavior: (a) greater susceptibility than adults to external influences such as peer pressure, and (b) less fixity of personality traits than adults and, therefore, better candidates for rehabilitation than adults (Steinberg, 2013).

4. ⁴ The words of Justice Kennedy in his majority opinion in Roper v. Simmons (Steinberg, 2013).

5. ⁵ Note that the immaturity argument would not apply to the impulsivity of immature adults since, unlike the adolescent, their immaturity is characterological rather than developmental (Steinberg, 2009).

6. ⁶ It should also be noted that there are several prefrontal cortical networks involved in regulating attention, cognitive control, emotional control, and motivation and not all of them are involved in ADHD. See Arnsten and Rubia (2012) for a granular analysis of these various circuits.

7. ⁷ Numerous randomized, controlled studies have documented the markedly beneficial short-term effects of stimulant medications on symptoms of ADHD with success rates of about 80% that are much higher than placebo rates (American Academy of Pediatrics, 2011; Barkley, 2013; Brown, 2013; Hinshaw & Scheffler, 2014; Volkow & Swanson, 2013). Indeed, with regard to the differential rate of success between stimulant medication and placebo, “There is no medication for any mental health condition that approaches this differential” (Hinshaw & Scheffler, 2014).

8. ⁸ It is beyond the scope of this article to discuss such procedures. For more recent iterations on these procedures, the reader can consult, inter alia: American Academy of Pediatrics (2011); Barkley (2013); Brown (2013); Hinshaw & Scheffler (2014).

9. ⁹ The five levels are total absence of responsibility, severely diminished responsibility, diminished responsibility, slightly diminished responsibility, and complete responsibility (van der Leij et al., 2001).