Study: NCT00713583

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: levodopa
Description: 800mg levodopa and 200mg carbidopa per day

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Placebo
Description: Placebo

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Cognitive Behavioral Therapy
Description: Participants received individual cognitive behavioral therapy (CBT) in 50-minute weekly sessions. These sessions were manual-driven and based on the relapse prevention model proposed by Marlatt and Gordon (1985). Trained masters-level therapists, under the supervision of senior therapists and the principal investigator, worked with participants to teach them how to recognize and cope with risky situations that could influence their cocaine use through self-monitoring of situational craving and drug use stimuli, coping skills training, and lifestyle modifications.

Intervention type: BEHAVIORAL
Group type: PLACEBO_COMPARATOR
Intervention: Cognitive Behavioral Therapy
Description: Participants received individual cognitive behavioral therapy (CBT) in 50-minute weekly sessions. These sessions were manual-driven and based on the relapse prevention model proposed by Marlatt and Gordon (1985). Trained masters-level therapists, under the supervision of senior therapists and the principal investigator, worked with participants to teach them how to recognize and cope with risky situations that could influence their cocaine use through self-monitoring of situational craving and drug use stimuli, coping skills training, and lifestyle modifications.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Contingency Management
Description: An abstinence-based contingency management (CM) procedure was used. Participants earned vouchers according to the reward schedule recommended by Budney and Higgins (1998), beginning at $2.50 for the first cocaine-negative urine. For each consecutive cocaine-negative urine, voucher values increased by $1.25 with a $10 bonus given for provision of three consecutive cocaine-negative urines within a week. A cocaine-positive urine or failure to provide a scheduled urine sample resulted in a reset of the schedule to the initial value of $2.50. After provision of five negative urines, the voucher returned to the value prior to the reset. Participants were able to redeem their vouchers for small amounts of cash (≤$25) or gift cards for goods and services.

Intervention type: BEHAVIORAL
Group type: PLACEBO_COMPARATOR
Intervention: Contingency Management
Description: An abstinence-based contingency management (CM) procedure was used. Participants earned vouchers according to the reward schedule recommended by Budney and Higgins (1998), beginning at $2.50 for the first cocaine-negative urine. For each consecutive cocaine-negative urine, voucher values increased by $1.25 with a $10 bonus given for provision of three consecutive cocaine-negative urines within a week. A cocaine-positive urine or failure to provide a scheduled urine sample resulted in a reset of the schedule to the initial value of $2.50. After provision of five negative urines, the voucher returned to the value prior to the reset. Participants were able to redeem their vouchers for small amounts of cash (≤$25) or gift cards for goods and services.