Julie Schweitzer, impulse investigator

Propelled by curiosity to pick up a magazine her mother had abandoned, nine-year-old Julie Schweitzer discovered an article written by the mother of an autistic child. Touched by the woman’s account of the daily struggle of raising a child who had what was at the time considered a relatively rare disorder, that article sparked Schweitzer’s lifelong interest in neurodevelopmental disorders. In graduate school, she shifted her attention toward attention deficit hyperactivity disorder, eventually earning her Ph.D. in psychology. She now serves as director of the Attention Impulsivity Regulation/ADHD Program at the UC Davis MIND Institute. She and her team recently received a $3.7 million grant to continue their study on impulsivity.

You are currently studying changes in impulsivity and self-control in teens and young adults over time. That seems difficult to quantify. How do you study it?

We use rating scales and questionnaires that the volunteers and their parents complete on the volunteers’ behavior; several behavioral tasks assessing impulsivity and response to reward [would you rather have $1 now or $20 in a week, for example]; and we assess brain activity while they are performing behavioral tasks. We also ask them about their everyday behavior in relation to impulsivity and risk taking: “Do you wear a helmet when riding a bike?” “Do you wear a seat belt?” “Have you driven a car while drinking alcohol or texting?”

Are you at all concerned that your subjects will exhibit less impulsivity—or perhaps more—because they know you are looking for it? How do you combat that?

Yes, I am very concerned about this issue, and we have devoted years to choosing measures and procedures to try to minimize the effect [of] the artificiality of the laboratory. For example, our volunteers have the opportunity to earn cash on the day of testing, and there are data showing that persons who are more impulsive are likely to be influenced by knowing the cash is immediately available.

Why is impulsivity such a concern in the first place? Isn’t it just a regular part of growing up?

Impulsivity is associated with major problems, including much higher accident rates, substance-use disorders, poorer academic and occupational functioning and many more issues. Impulsive behavior is on a spectrum, however, and our recent project is specifically evaluating how the degree of impulsive behavior changes with development, and how the degree of impulsivity relates to real-world outcomes.

What is your goal with this study?

The long-term goals of the project are to inform our understanding of development during this critical period, and identify those who are at risk due to impulsive decision-making—to inform targeted prevention and intervention strategies to reduce impulsivity and improve long-term outcomes for those at risk for harm.

How did you come to be awarded this grant?

With great teamwork! I work with a wonderful group of bright, innovative, tremendously hard-working individuals, including many laboratory members, faculty and students at UC Davis. Much of the best science today requires teamwork, and I am honored to work with so many talented, smart [and] devoted researchers. I also am very grateful to the volunteers and families who give their time to participate in our research.

What will this mean for your study?

With this new funding, we will continue to follow the original volunteers for five years up to early adulthood, whereas before most of our testing stopped during the teen [years] through about 25 years of age. We will now be able to work with volunteers during a developmental period associated with greater emergence of psychological problems, emotional instability and self-harm behaviors. Also, we will be able to identify at what age brain development likely completes in ADHD. We now know that in typically developing individuals the brain completes most of its development by 26 years of age, but it is unknown when brain development completes in [people with] ADHD …

How are ADHD and impulsivity related?

Some individuals with ADHD have a significantly higher rate of impulsivity. Not all individuals with ADHD have impulsivity, but many do. Impulsivity and poor academic functioning are two primary reasons that persons come in for treatment of ADHD.

ADHD seems to be an increasing concern of parents and educators. Can you shed some light on this?

First, there is a greater recognition of ADHD and its negative outcomes; second, there is greater appreciation that ADHD occurs in other groups who were not associated with ADHD in the past [females; adults] and those with the inattentive type of ADHD; third, there is greater pressure and competition for students to perform in the academic setting. I am also concerned that evaluations for ADHD are not sufficiently thorough.