Impulsivity, Brain Function, and Substance Abuse Treatment in Cocaine Dependent Individuals

Cocaine is a strong central nervous system stimulant that is widely abused throughout the
United States. Due to its widespread use, it is important to develop an effective treatment
for cocaine dependence. The purpose of this study is to determine how impulsivity and
prefrontal cortical function are related to treatment response in cocaine dependent
individuals.

Participants in this study will complete four separate experiments, each with a different
aim and testing panel [cognitive function tests with and without functional magnetic
resonance imaging (fMRI)]. The first experiment will examine memory, attention, cognitive
function, and impulsivity; the aim is to determine the relationship between impulsivity and
cognitive function in cocaine dependent individuals receiving treatment. The second
experiment will examine the relationship between impulsivity and the prefrontal cortical
structure and function. Participants will complete an fMRI during the second experiment.
The third experiment will consist of cognitive function tests and will examine the
prefrontal cortex in relation to treatment response, based on four different treatments: 1)
L-dopamine, 2) naltrexone, 3) modafinil, and 4) placebo. The fourth experiment will examine
the effect of cocaine dependence treatment on prefrontal cortex, focusing on participants
receiving modafinil.

Inclusion Criteria:

- Meets DSM-IV criteria for cocaine dependence

- Met inclusion criteria for other cocaine dependence studies within the center grant

Exclusion Criteria:

- Current or history of DSM-IV Axis I disorders, other than substance abuse or
dependence

- Lifetime diagnosis of alcohol dependence

- Serious non-psychiatric medical illness requiring ongoing medical treatment or one
that affects the central nervous system

- Positive urine drug screen test for drugs of abuse other than cocaine at the time of
study entry

- AIDS-defining illness

- Intelligence Quotient (IQ) below 70

- Pregnant

- Uses a pacemaker, metal or electromechanical implants, or metallic foreign bodies