Experts Seek Answers Behind Impulsive Behavior

Suddenly Johnny's "strong will" has turned into temper tantrums. The "inquisitiveness" that seemed so precocious has become disruptive at school. His "cute" little way of always blaming his misbehavior on his little sister, has become chronic lying and excuse peddling. While he says he's "standing up for himself," he's known in the neighborhood as a bully.

Truth is, if Johnny's behavior isn't challenged and corrected, he is headed for a very difficult life. Without intervention, he may develop a more serious disruptive behavior, Conduct Disorder, characterized by overly aggressive behavior toward people and animals.

Children with conduct disorder aren't just defiant, rude or aggressive. They repeatedly commit acts that seriously violate personal and societal rights and rules. They set fires, steal, run away from home, are truant from school, and most troublesome, commit aggressive acts which harm animals and other people, sometimes using a weapon.

Too often, anti-social criminal and violent behavior escalates. Incarceration and imprisonment might remove these predatory children from the streets, but it doesn't really help them, especially if there is not some kind of psychological intervention.

For the past several years, a group of psychiatric physicians and psychological researchers at The University of Texas-Houston Mental Sciences Institute (MSI) have been working to understand the very basis of such behaviors. Their goal is to understand human impulsivity, and they have conducted a number of studies with varying populations to develop ways to assess and properly diagnose and treat such disorders.

During the past year, this group, which includes Drs. Alan Swann, F. Gerald Moeller and Donald Dougherty, have, for the first time at Harris County Psychiatric Center (HCPC), focused on impulsivity in adolescents. Working under their guidance and with the help of attending psychiatrists at HCPC, postdoctoral research fellow Dr. James Bjork has been conducting studies with inpatient adolescents at HCPC to learn more about dangerous impulsive behavior.

"We define an impulsive person, "Dr. Bjork says, "as someone who acts before he thinks and finds himself in trouble before he thinks about the consequences. Impulsive people often later express remorse for what they've done."

"Our ultimate goal is to establish risk factors and measures for impulsive behavior which could lead to the prevention of conduct disorder in children, progressing to adult antisocial personality disorder, substance abuse, and violence," says Dr. Moeller.

"The primary purpose of this research," Dr. Bjork explains, "is to evaluate newly programmed computerized measures that we think will tap into impulsivity in children. We want to establish the credibility of these tasks by comparing the performance of a group of adolescents - known to have such problems or diagnosed with conduct disorder - on these tasks with the performances of a `control' population of teens who have no such history.

"We're trying to determine the `external validity' of these measures," he says, "in other words, we're trying to show that these laboratory tasks measure what translates into real world behavior."

The research project also has two other components: to compare the children with their parents to understand both the biological and environmental components of impulsivity and to look at the basic biology of human aggression, especially as it relates to the neurotransmitter serotonin.

These tests, he explains, are not meant to be used by a psychologist trying to diagnose a child's problem, but by researchers who are studying the biology of impulsivity.

Although such ways of determining a person's impulsive nature are being developed and tested at other centers around the country, the UT-Houston program is the only one which is also giving the same assessments to the parents of the children in the study.

In cooperation with attending physicians Drs. Kathy Scott-Gurnell and Andrew Harper, Dr. Bjork conducted interviews and studied case histories of adolescent patients, ages 13 to 17, with impulse control problems or who were admitted to HCPC because of an impulsive or aggressive act (such as setting fires). Dr. Bjork also recruited a control group of "normal" adolescents from the community.

They were asked to do three computerized tasks that the researchers think can tap into various aspects of impulsiveness. The first is derived from the Continuous Performance Test (CPT) which Dr. Dougherty used with adults, the second, a "Go-No Go" test, and the third, the SKIP test or (Single Key Impulsivity Paradigm). All involve a person's ability to take an action before thinking about its consequences - the definition of impulsive behavior.

The CPT test, Dr. Bjork says, demonstrates how well a person can instantaneously process what he or she sees. The computer screen flashes on and off a random sequence of five-digit numbers every few seconds and the teens are told to click only when they see the same number twice in a row. "Everyone will make mistakes on this test, but we're finding," Dr. Bjork says, "that the adolescents with impulse control problems are making more fast guess/false alarm responses than the control group - demonstrating that these children have an inability to withhold an inappropriate response."

The second task, Dr. Bjork explains, or the "Go-No Go," is like the CPT, but it looks at how fast a person can put the brakes on or stop a response.

"The take-home message is that, in these children, "the go" oriented neural centers of the brain may be much more vigorously activated relative to the inhibitory or "no-go" neural centers. And these children's behaviors in the real world (many are or have been involved in the juvenile justice system) adds validity to this finding."

The final task, the SKIP, is designed to discover if a child can hold off on making a reward-directed response - delayed gratification. This task, too, is computerized, and involves how often and fast subjects click their mouse to earn a reward.

Once again, the results comparing the impulsive children with the control group, demonstrated the inability of the impulsive children to wait - even to gain a reward - between responses, as the control children.

"This kind of basic research may not attract a lot of attention, but it's necessary to establish the validity of these measures, because if we can demonstrate that we are getting differences between children who do and do not have impulsivity issues, we can then use these new laboratory tests, for example, to look at what effects treatment has on these measures," says Dr. Bjork.

In giving these same tasks to the parents of patients in the study who agreed to participate, Dr. Bjork has found that the parents perform less impulsively than their children, even the parents of more aggressive children. "I believe this is because the parents are more able to inhibit these responses than their children. But you can absolutely see the correlation in statistics within the parent/child pairs."

The final portion of the study will determine the effect that one of the neurotransmitters, GABA, has on impulsive or aggressive behaviors. "We're collaborating with the Dallas Veterans Administration to look at GABA's effect on adults. There is a lot of physiological evidence that the level of GABA in the blood is related to the level of GABA in the brain. What we've found is that the higher the GABA level, the less aggressive the personality, as reported by the adults themselves. Now we will use the subjects' blood from this study to see if the same holds true for adolescents: do their GABA levels relate to their impulsive behavior histories or their performance on the three tasks.

"I think the biggest benefit to this research will be the development of alternative interventions to incarceration. I'd like to see if we can keep kids out of jail by identifying those at risk and getting them help via medications or more structured environments," says Dr. Bjork.

Drs. Scott-Gurnell and Swann are currently devising a possible research protocol, implementing Dr. Bjork's findings, to look at the effects of medication on impulsive patients.

But can these treatments really make a difference in a child with conduct disorder?

"In my many years as a child psychiatrist, I have only seen one child for which I thought it was too late," answers Dr. Scott-Gurnell. Echoing Dr. Bjork's beliefs, she believes that "when you talk with them one-on-one, move them from their environment and their other negative stimulants, there is hope in most of those children.

"Sometimes children who are incarcerated in a prison or detention facility, learn to increase their aggressive behaviors in order to survive in the system. This medication - pharmacological intervention - can be very important in actually changing behavior and turning that child around.

"The first signs of Conduct Disorder occur before age 15. I am not a clinician, but my hope would be that we could help kids whose environment seems to promote confrontational behaviors," she says.

"I imagine," Dr. Bjork says, "that there are large populations of offenders out there who have `short fuses' and who know, intellectually, that harming another person is wrong, but when they are presented with the aversive stimulus they just go off. If we can better understand the biochemistry that characterizes those violence-prone individuals, there could be pharmacological approaches to help take the `edge' off that behavior and help people get through these crises, prevent violence or criminal behavior later on."

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©2006 Texas Medical Center

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