Effects of Smoked Marijuana on Risk Taking and Decision Making Tasks

Phase 1

Completed

Conditions: Marijuana Use Disorder

Interventions: Drug: Inactive Marijuana (0% THC)
Drug: Low THC marijuana (1.8 %THC)
Drug: High THC marijuana (3.9% THC)

Registration Number: NCT00373399

Lead Sponsor: New York State Psychiatric Institute

Brief Summary: The purpose of this study is to investigate the effects of smoked marijuana on both risk taking and decision making tasks.

Detailed Description: Cannabis abuse and dependence are the most prevalent drug use disorders in the United States (Compton et al., 2004), yet little is known about the factors contributing to successful marijuana treatment. Previously, we have shown that cognitive impairments in patients treated for substance disorders are associated with premature treatment dropout. However, little is known about whether such impairments are the result of drug use per se. The objective of this within-subject study is to determine whether decision-making and risk-taking are affected by acute cannabis intoxication. The Balloon Analogue Risk Task (BART; Lejuez et al. 2002) assesses decision making in a context of increasing risk, and the Iowa Gambling Task (IGT; Bechara et al. 1994) tests the ability to balance immediate rewards against long-term negative consequences; both tasks have strong face validity for evaluating cognitive deficits that may contribute to poor treatment outcome. Research volunteers will be current marijuana smokers. Each will participate in three, 4-hour outpatient sessions in the Substance Use Research Center (SURC) in the Division of Substance Abuse at NYSPI. They will smoke a different strength marijuana cigarette (0.0, 1.98, 3.9% THC) in each session in counter-balanced order. After baseline data have been collected (risk taking and decision making behaviors, heart rate, blood pressure, mood scales, exhaled carbon monoxide), participants will take 3-6 puffs, 5 seconds in duration, from a National Institute on Drug Abuse (NIDA) marijuana cigarette. After smoking, we will repeatedly re-assess risk taking and decision making abilities with the BART and IGT. We will also measure subjective mood ratings, heart rate and blood pressure repeatedly for 180 minutes following smoking. This study is the first controlled investigation of the effects of smoked marijuana on both risk taking and decision making tasks. The data obtained will be used to guide treatment development for marijuana use disorders.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 36

Inclusion Criteria

Current marijuana use
21-45 years of age
Practicing an effective form of birth control
Not seeking treatment for marijuana use

Exclusion Criteria

Current, repeated illicit drug use other than marijuana
Presence of significant medical illness (e.g., diabetes, cardiovascular disease, hypertension)
Laboratory tests outside normal limits that are clinically unacceptable to the study physician (BP > 140/90; hematocrit < 34 for women, < 36 for men)
Significant adverse reaction to marijuana
Current parole or probation
Pregnancy or current lactation
Recent history of significant violent behavior
Major current Axis I psychopathology (e.g., mood disorder with functional impairment or suicide risk, anxiety disorder, schizophrenia
History of heart disease
Current use of any over-the-counter or prescription medication from which the volunteer cannot be withdrawn

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Inactive Marijuana (0, 1.8, or 3.9% THC)	Inactive Marijuana (0% THC)	In this randomized, placebo-controlled study, every participant received all 3 treatment interventions in randomized order. Inactive marijuana (0% THC) served as a placebo comparator. Participants received an inactive marijuana cigarette (0% THC; provided by NIDA) in 1 of the 3 outpatient sessions in randomized order.
Active Marijuana	Low THC marijuana (1.8 %THC)	In this randomized, placebo-controlled study, every participant received all 3 treatment interventions in randomized order. Participants received active marijuana cigarettes (1.8, or 3.9% THC; provided by NIDA) over 2 of 3 outpatient sessions in randomized order.
Active Marijuana	High THC marijuana (3.9% THC)	In this randomized, placebo-controlled study, every participant received all 3 treatment interventions in randomized order. Participants received active marijuana cigarettes (1.8, or 3.9% THC; provided by NIDA) over 2 of 3 outpatient sessions in randomized order.

Primary Outcome Measures

Name	Time	Method
Change From Baseline in Iowa Gambling Task Scores [Objective Measure of Decision Making]	3 weeks	A modified version of the Gambling Task (Bechara et al., 1994) was used. Four decks of cards (A-D) were displayed on a computer screen. Volunteers were told that the objective of the game was to win as much money as possible. They were also told that the game entailed a series of card selections from any of the decks, one card at a time, and that they should select cards until instructed to stop. The task was stopped after 100 card selections or after 5 min had elapsed. Data indicate change from baseline in mean number of cards selected from advantageous decks minus number of cards selected from disadvantageous decks as a function of drug condition. Higher numbers indicate better decision making regarding advantageous cards. Planned comparisons using single degrees of freedom, generated by a two-tailed repeated measures analysis of variance (ANOVA), were used to examine the effects of THC concentration (0% vs. 1.8%, 0% vs. 3.9%, and 1.8% vs. 3.9%) on task performance.

Secondary Outcome Measures