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. Author manuscript; available in PMC: 2013 Aug 1.
Published in final edited form as: Am J Psychiatry. 2012 Aug 1;169(8):805–812. doi: 10.1176/appi.ajp.2012.12010055

Table 2.

Study Outcome Measures.

Study Outcome Measures Results
Primary Outcome
Measure
Overall Treatment Effect % Negative Urine
Cannabinoid Test		 Odds Ratio 95% CI p-value
NAC 40.9 % 2.35 1.05-5.24 0.029
Placebo 27.2 %
Secondary Outcome
Measures
Time to First Negative
Urine Cannabinoid Test		 Median Days Hazard Ratio 95% CI p-value
NAC 17 1.48 0.87 - 2.49 0.146
Placebo 24
2 Week Urine Cannabinoid
Test Confirmed End of
Treatment Abstinence		 % Abstinent Odds Ratio 95% CI p-value
NAC 36.2 % 2.32 0.99 - 5.43 0.054
Placebo 20.7 %
4 Week Urine Cannabinoid
Test Confirmed End of
Treatment Abstinence		 % Abstinent Odds Ratio 95% CI p-value
NAC 27.6 % 2.14 0.85 - 5.42 0.108
Placebo 15.5 %
Change in days using
cannabis during treatment		 % Change Mean Difference 95% CI p-value
NAC 41.1 ± 4.3 % −4.0 ± 6.0 −15.8 – 7.9 0.512
Placebo 37.0 ± 4.4 %

Overall Treatment Effect: Generalized estimating equations analysis of negative urine cannabinoid tests during the 8-week treatment. Data are shown as the mean proportion of negative urine cannabinoid tests and associated adjusted odds ratio. Data analysis was conducted on an intent-to-treat sample (n=116) in which those with missing data / lost to follow up were considered non-abstinent. Results shown are adjusted for baseline urine cannabinoid test results, years of reported cannabis use, and major depressive disorder.

Time to First Negative Urine Cannabinoid Test: Data are shown as median number of days to the first negative urine cannabinoid test. Results are shown as adjusted hazard for time to first negative urine cannabinoid test for N-acetylcysteine versus placebo participants (n=116). Results shown are adjusted for baseline urine cannabinoid test results and years of reported cannabis use.

End of Treatment Abstinence (2 and 4 week): Results are shown as the 2 and 4 week urine cannabinoid test confirmed continuous self-reported abstinence at the end of treatment. Results are shown as the odds of abstinence in N-acetylcysteine versus placebo participants. Data analysis was conducted on an intent-to-treat sample (n=116) in which those with missing data / lost to follow up were considered non-abstinent. Results shown are adjusted for baseline urine cannabinoid test results and years of reported cannabis use.

Proportion of Days Using Cannabis: Data are shown as the adjusted change in percent of days with self-reported cannabis use between the treatment phase of the study and the 30 days prior to study entry. Results are shown as the mean difference between the proportion of days used in N-acetylcysteine versus placebo participants and associated standard error (n=89 participants with self-report data available), and are adjusted for baseline urine cannabinoid test results, years of reported cannabis use at entry into the study, and self-reported percent of days used in the 30 days prior to study entry.

NAC=N-Acetylcysteine