Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most common childhood psychological disorders. The symptoms of ADHD include difficulties focusing attention, trouble with impulsive behavior, and hyperactivity or restlessness. Scientists have shown that people with ADHD process information differently than people without ADHD. One theory that has been proposed to explain this difference is that the brains of people with ADHD mature and develop more slowly than the brains of people without ADHD.

We are examining the brain changes that occur during adolescence and into adulthood and how those changes are related to the symptoms of ADHD. We do this using functional magnetic resonance imaging, fMRI. fMRI is a 3-dimensional picture of the brain using magnetic waves. When participants perform cognitive tasks in an fMRI machine we can see what areas of the brain are activated by these tasks. Understanding these changes through development and aging may be useful for understanding how ADHD changes as people get older, and may help us to develop better treatments for ADHD in the future.

Nicotinic Stimulation in Attention-Deficit/Hyperactivity Disorder (ADHD) Adolescents who suffer from Attention-Deficit/Hyperactivity Disorder (ADHD) become cigarette smokers and tobacco users at twice the rate of non-ADHD adolescents. While ADHD first appears in childhood the symptoms persist into adolescence and adulthood for up to 80% of people who are diagnosed as children. Similarly, the high rate of tobacco use continues into adulthood. The reasons for this vulnerability of people with ADHD to tobacco are poorly understood.

One possible reason is that nicotine, the psychoactive component of tobacco, may produce positive effects on attentional performance in ADHD adolescents. ADHD produces specific attentional difficulties which are partially ameliorated by medications that enhance dopaminergic functioning in the brain. Extensive studies of nicotine over several decades from our laboratory and others have demonstrated that nicotine has significant attentional and cognitive-enhancing effects even in clinical populations with neuropsychiatric disorders. It is therefore possible that tobacco use in adolescents serves as a form of self-selected medication to improve some of the cognitive difficulties associated with ADHD.

We are examining whether nicotine, the psychoactive constituent of tobacco, may have positive effects on cognitive and motor processes involving attention that appear to be impaired in many adolescents and young adults with ADHD. The primary aim of these studies is to examine the effects of acute nicotinic stimulation on a measure of behavioral inhibition, decision-making, and motor performance in adolescents and adults with ADHD. These results should provide significant information as to some of the reasons for the vulnerability of the ADHD population to high rates of tobacco use, and may help in the future development of better and safer alternative treatments for ADHD.

We are also studying the effects of nicotine on cognitive processes in other disorders like schizophrenia and Parkinson's disease. For more information go to our Nicotinic Research and Therapeutics Program page.

Faculty associated with these projects include:

• Alexandra Potter, Ph.D.

Cognitive Processes in ADHD - A Brain fMRI Study

In this study we want to see how the brains of adults with ADHD function differently when asked to do tasks involving attention, memory, and impulsivity using functional magnetic resonance imaging (fMRI, a brain scan). To this end we are recruiting 100 non-smoking adults (18-65), 50 with and 50 without ADHD, and asking them to participate in one or two 2-hour study days in which they will perform computer tasks while in the fMRI scanner.

Neurobiological Underpinnings of Cognition in Neurodevelopmental Disorders

This research is aimed at studying the brain function of two young age groups to better understand the neurobiological underpinnings of ADHD from a developmental aspect. We are testing how the brains of people with and without ADHD process information, as well as how teenagers process information differently than adults. We will be studying adolescents (13-18) and young adults (21-26) with and without ADHD. Participants will come to the hospital for two 2-hour study visits during which they will perform a computer task while in the fMRI scanner.

Nicotine Brain Study

The goal of this study is to use functional MRI to examine how nicotine improves impulse control and working memory in young adults (18-25) who either have or do not have ADHD. This study will look at patterns of brain activation associated with nicotine and methylphenidate (Ritalin, a common treatment for ADHD) to help understand how the differences in the brain functioning of people who have ADHD may affect their behavior. We are looking for 24 non-smoking young adults (18-25) who have, and 24 who do not have, ADHD. The volunteers will complete three 6-hour study visits in which they will receive nicotine alone, methylphenidate alone, or placebo and then be asked to perform computer tasks in the fMRI.