Long-Term Heavy Recreational Cannabis Use and Serum Delta-9-Tetrahydrocannabinol Levels are not Associated with an Impaired Liver Function in Cannabis Dependents

To shed more light on the influence of chronic cannabis use on liver function, we performed a post-hoc analysis of routine lab data of 42 inpatient treatment-seeking (9 female, median: 27 years old) pure cannabis dependents. Serum liver function tests (LFT: transaminases, bilirubin), C-reactive protein (CRP), carbohydrate-deficient transferrin (CDT), and body mass index (BMI) were considered. The LFT were correlated with CDT, BMI, and cannabis-related clinical data (CR); i.e., the serum levels of delta-9-tetrahydrocannabinol (THC) and its major metabolites 11-hydroxy-delta-9-tetrahydrocannabinol (THC-OH) and 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), plus the cannabis-history data. The LFT was normal in 32 (76.2%) patients. There was no significant association of LFT with BMI, CRP, CDT, and CR. No significant differences were found between the group with elevated LFT (N = 10) and the group without elevated LFT (N = 32) regarding BMI, CRP, CDT, and CR, except for THC-OH, which was even lower in the elevated-LFT group. These results argue against a relevant harmful impact of chronic cannabis inhalation on the liver function of relatively healthy humans (apart from nicotine dependence). Specifically, the liver function tests were not significantly influenced by THC and THC-COOH levels, both objective markers for the amount and duration of prior cannabis use.