Age-Related Changes in Quantitative EEG in Attention- Deficit/Hyperactivity Disorder Susan M. Bresnahan, John W. Anderson, and Robert J. Barry Background: Attention-deficit/hyperactivity disorder (ADHD) in children and adolescents is characterized by excessive restlessness and an extremely poor concentra- tion span, resulting in impulsive and disruptive behavior. Clinical observation of ADHD in adults suggests that the hyperactivity component is diminished although the im- pulsive type behaviors remain apparent. EEG studies of children and adolescents with ADHD have reported sig- nificantly higher levels of low frequency activity (predom- inantly theta) and lower levels of beta activity than normal controls. Methods: We examined the relationship between the age-related changes reported in clinical observation and changes in EEG activity occurring in a group of ADHD patients ranging in age from 6 to 42 years. Quantitative EEGs were obtained from the midline sites of 25 children, 25 adolescents and 25 adults diagnosed with ADHD, and compared with those of age matched normal controls. Results: Theta activity was elevated in the ADHD groups across all age groups compared with the normal controls. The extent of the reduction in relative beta activity in the ADHD groups compared to normal controls decreased with increasing age. Conclusions: Given that the hyperactivity component in ADHD reduces with age while the impulsivity component remains, these data, in ADHD, suggest that decreased beta activity may be linked to hyperactivity and increased theta activity to impulsivity. Biol Psychiatry 1999;46: 1690 –1697 © 1999 Society of Biological Psychiatry Key Words: Quantitative EEG, attention deficit hyperac- tivity disorder, children, adolescents, adults Introduction H istorically, many diagnostic labels have been used to describe what is currently termed attention-deficit/ hyperactivity disorder (ADHD). The essential diagnostic criteria for the disorder, however, remain unchanged, and include developmentally inappropriate levels of impulsive, hyperactive and inattentive behaviors. It is these behaviors that affect almost every area of daily functioning. ADHD is now recognized as a common childhood disorder and the DSM IV (American Psychiatric Association 1994) estimates that 3–5% of school-age children are affected. In adolescence and adulthood, data and information on prev- alence is not available. Until recently, it was assumed that children outgrew ADHD by the time they reached puberty as a result of developmental changes. Clinical observation now suggests that as children and adolescents with ADHD mature, the number and intensity of their symptoms reduce but they remain impaired. According to Barkley (1990), the primary characteris- tics of inattention, behavioral inhibition and hyperactivity persist into the adolescent years in 70 – 80% of children with ADHD. Poor organization, behavioral inhibition and difficulties in task completion present as the predominant symptoms, along with problems relating to discipline, antisocial behavior, poor performance at school and prob- lems with peer relationships. Barkley (1991) reported that adolescents with ADHD display significant impairments in attention, impulsivity and overactivity, along with academic achievement, social competence and behavioral adjustment. It is also reported that during adolescence there is a higher risk for associated comorbid disorders including conduct disorder, antisocial disorder and oppo- sitional defiant disorder (Wender 1995a). Studies carried out over the past two decades (e.g., Brown and Borden 1986), have demonstrated that although there is a reduc- tion in the degree of hyperactivity, in general, the impul- sive and inattentive behaviors continue. Studies assessing the clinical presentation of ADHD in adulthood have identified a range of symptoms thought to constitute an adult form of the condition. Hechtman et al (1981) identified 3 categories of outcome in adults with the disorder. First there are adults who essentially function normally. Second, there are adults who continue to display significant problems with concentration, social integra- tion, emotional and impulse control, that impact nega- tively on their work, relationships and self esteem, leaving them anxious, emotionally labile and irritable. There is From the Department of Psychology, University of Wollongong, Wollongong (SMB, RJB) and NPS ADD Clinic, Westmead (SMB, JWA), New South Wales, Australia. Address reprint requests to Robert Barry, Department of Psychology, University of Wollongong, NSW 2522, Australia. Received July 29, 1998; revised February 4, 1999; accepted February 10, 1999. © 1999 Society of Biological Psychiatry 0006-3223/99/$20.00 PII S0006-3223(99)00042-6