Diagnostic Criteria

Both the fourth text revision and the newly published fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR, DSM-5) (American Psychiatric Association [APA], 2000, 2013) differentiate among three presentations (formerly subtypes) of the disorder: predominantly inattentive, predominantly hyperactive/impulsive, and combined. These presentations are distinguished by specific clusters of symptoms present in the individual. To receive a diagnosis of ADHD, a child or adolescent must demonstrate at least six symptoms of inattention (inattentive presentation), hyperactivity/impulsivity (hyperactive/impulsive presentation), or inattention and hyperactivity/impulsivity respectively (combined). Furthermore, symptomatology must be present for at least 6 months and must coincide with functional impairment in at least two settings (e.g., home, school, with peers).

Four notable changes in the diagnostic criteria for ADHD were made in the DSM-5.

1. The threshold of symptoms needed for an adult diagnosis was lowered, given the reduction of symptoms that seem to manifest in adulthood (Kessler et al., 2010).
   
2. Whereas the DSM-IV-TR specified that symptoms must be present before age 7, in the DSM-5 the age of onset was increased to age 12. Research published since the DSM-IV-TR has not found significant differences in functioning, treatment response, or outcomes in comparing youth meeting an earlier relative to a later age of onset threshold (Todd, Huang, & Henderson, 2008).
   
3. It is no longer necessary for symptoms to be accompanied by impairment across multiple settings for an individual to meet diagnostic criteria for ADHD; rather, symptoms must exist across settings.
   
4. Whereas the DSM-IV-TR required “clear evidence of clinically significant impairment in social, academic, or occupational functioning” (APA, 2000 p. 93), language in the DSM-5 has been modified: “clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning” (APA, 2013, p. 60).

Thus, recent changes to the diagnostic criteria for ADHD represent advances in the scientific understanding of the disorder and better account for potential diagnostic presentations that may change across the life span.

From a developmental psychopathology perspective, ADHD-associated impairment also changes across development (Seidman, 2006). For instance, toddlers may demonstrate some of the core symptoms typically associated with ADHD (e.g., high energy); however, such symptoms generally are not accompanied by impairment (Campbell & von Stauffenberg, 2009). Longitudinal research suggests that by age 3 or 4, hyperactive/impulsive symptoms can be distinguished from normative disinhibition by virtue of both symptom severity and corresponding impairment (Barkley, 2003).

The demands in middle childhood, such as increased standards for self-control and self-monitoring and expectations of cooperation with family and peers, present many potential ways in which symptoms of ADHD may interfere with functioning. Within the home environment, research suggests that ADHD negatively impacts both the parent–child relationship and overall family functioning (for a review, see Deault, 2010). Parents of children with ADHD report significantly higher levels of parenting stress relative to children without ADHD (Mash & Johnston, 1983). Higher levels of parenting stress among families affected by ADHD may erode parents’ ability to engage in effective parenting strategies in order to manage their children’s behavior (Podolski & Nigg, 2001). As such, parent–child relationships are often characterized by greater negative emotionality, conflict, and coerciveness (DuPaul et al., 2001) relative to families of children without ADHD. Family functioning is also often affected, with greater family discord (Wells et al., 2000) and higher rates of divorce (Wymbs et al., 2008) observed among families of children with ADHD.

Within the school environment, children in middle childhood with ADHD have significant educational difficulties, including academic underachievement (DeShazo Barry, Lyman, & Klinger, 2002; Fergusson & Horwood, 1995; Fergusson, Horwood, & Lynskey, 1993) relative to control youth. Such children are also more likely to repeat academic grades (Hinshaw, 1992) and receive remedial services (Frick et al., 1991) and are more apt to face school-related disciplinary action (e.g., suspensions) compared to children without the disorder (Loe & Feldman, 2007). They are also more apt to exhibit social impairment. In fact, children with ADHD receive significantly fewer social nominations relative to their nonaffected peers (Hoza, 2007). It may be that the core symptoms of ADHD directly and negatively impact children’s ability to establish and maintain peer relationships. Indeed, Whalen and Henker (1992) found that the high levels of impulsivity and hyperactivity often seen in youth with ADHD are found to be aversive and may distance such children from peer social networks. Alternatively, inattentive symptoms may deter children with ADHD from acquiring important social skills (e.g., conversational turn taking) through observational learning (Cunningham, Siegel, & Offord, 1985). The negative impressions made on peers during childhood are resistant to treatment and may continue throughout the school-age years (Price & Dodge, 1989). Thus, the core symptoms of ADHD often result in difficulties in establishing and maintaining healthy peer relationships during childhood.

Moving into adolescence, between 50% and 80% of clinically referred children will continue to experience ADHD-related impairment (Parke et al., 2002). While the symptoms of hyperactivity and impulsivity perhaps distanced middle-age children from their peers, there is evidence to suggest that, in adolescence, these symptoms may translate into greater engagement in risky behaviors, such as dangerous driving habits (Cantwell, 1996). Within the academic realm, adolescents with ADHD fail more classes (Mannuzza, Klein, Bessler, Malloy, & Hynes, 1997), require a greater number of years to graduate high school (Weiss, Hechtman, Milroy, & Perlman,1985), and have lower rates of college attendance and graduation (Barkley, 2006) relative to controls. Research suggests that in adolescence, symptoms of hyperactivity may wane. However, impulsivity and inattention symptoms remain both prominent and impairing. Furthermore, among adolescents with ADHD, a sense of what has been termed “inner restlessness” may begin to pervade the clinical picture for these individuals (Harpin, 2005). Thus, there is evidence to suggest that in adolescence, symptom clusters may become more or less pronounced (i.e., shift from hyperactive to inattentive and impulsive), and types of impairment may also change.

Once conceptualized as a disorder of childhood, there is now evidence that ADHD is a chronic disorder, with symptoms and impairment continuing into adulthood (Pary et al., 2002). Adults affected by ADHD experience greater occupational difficulties (e.g., unemployment) (Mannuzza et al., 1997), have poorer health outcomes (Harpin, 2005), and have fewer intimate relationships (Weiss & Murray, 2003) relative to control adults. Clearly, ADHD has far-reaching developmental implications, as early deficits, particularly if left untreated, may place children with ADHD at risk for significant impairment across multiple domains over a lifetime.

Comorbidity

Complicating the clinical picture for many children with ADHD, comorbidity with other mental disorders is highly prevalent. The most common comorbid disorders are oppositional defiant disorder (ODD) and conduct disorder (CD). Barkley (2003) found that by age 7, 54% to 67% of clinically referred children with ADHD were also diagnosed with ODD. Barkley, Fischer, Smallish, and Fletcher (2004) found that between 20% and 50% of youth with ADHD went on to develop comorbid CD by middle childhood, and by adolescence, 44% to 50% met criteria for a dual diagnosis.

Comorbid internalizing disorders, including anxiety and depression, also are common. Tannock (2000) found that between 10% and 40% of children affected by ADHD within clinical samples are diagnosed with an anxiety disorder. Unlike CD, there is some evidence to suggest that anxiety may mitigate some of the negative consequences of ADHD (Pliszka, 2000). Fewer externalizing behaviors in general and less impulsivity in particular are evidenced among children with comorbid ADHD and anxiety (Jensen et al., 2001; Pliszka, 2000). As such, anxiety may buffer children with ADHD against some negative sequelae. ADHD is also highly comorbid with depression (Golubchik, Kodesh, & Weizman, 2013), with approximately 20% to 30% of youth meeting diagnostic criteria for both disorders (Barkley et al., 2004). Children with comorbid depression and ADHD may experience greater social and academic impairment relative to those children with ADHD alone (Blackman, Ostrander, & Herman, 2005). It is possible that social isolation and lack of motivation, two hallmark symptoms of depression, exacerbate existing social and academic impairment.

Finally, between 19% and 26% of children with ADHD also have a learning disorder (LD). Eighty percent of children with ADHD have learning difficulties that result in academic performance 2 years behind their nonaffected classmates (Barkley, 2003). A seminal study (Mayes, Calhoun, & Crowell, 2000) compared children with comorbid ADHD and LD to those with ADHD alone and found that both groups experienced significant learning difficulties. However, the difficulties were significantly more severe in the comorbid group, as could be expected. It is possible that LDs and specifically the inattention observed among those with ADHD represent disorders along a common spectrum.

Behavioral Interventions

Just as the symptoms and impairments exhibited by children with ADHD are varied, so too are the behavioral treatment strategies used to reduce these problems. Next we provide an overview of the types of treatment programs that have been examined in empirical research.

The strategies used by parents to increase compliant behaviors and decrease noncompliant behaviors can be implemented in the classroom as well. Teachers can implement reward systems for children with ADHD in the classroom using the same principles of reinforcement and punishment. The Daily Report Card (Chronis, Chacko, Fabiano, Wymbs, & Pelham, 2004; Smith, Waschbusch, Willoughby, & Evans, 2000) is a system that fosters collaboration and communication between parents and teachers. Teachers establish target behaviors, such as in-seat compliance, and send a “report card” home to parents, who then provide rewards.