Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, the Netherlands.
Addiction. 2014 Jul;109(7):1101-9. doi: 10.1111/add.12508. Epub 2014 Mar 17.
Increased delta-9-tetrahydrocannabinol (THC) concentrations in cannabis may lead to higher THC exposure, cannabis dependence and treatment need, but users may also adapt the actual intake of THC through reduced inhalation of THC containing smoke (titration). We investigated whether consumers of stronger cannabis use less cannabis per joint or inhale less smoke than those using less potent cannabis and whether these factors predict cannabis dependence severity.
Heavy cannabis users (n = 98) brought their own cannabis, rolled a joint and smoked it ad libitum in a naturalistic setting. We analysed the content of the joint, its association with smoking behaviour and the cross-sectional and prospective (1.5-year follow-up) relations between smoking behaviour and cannabis dependence severity (total number of DSM-IV dependence symptoms).
THC concentration in cannabis (range 1.10-24.70%) was correlated positively with cannabis dose per joint (b = 0.008, P = 0.01), but the resulting THC concentration per joint (range 0.24-15.72%) was associated negatively with inhalation volume (b = -0.05, P = 0.03). Smoking behaviour measures (number of puffs, inhaled volume, reduction of puff volume and puff duration while smoking) predicted follow-up dependence severity, independently of baseline dependence severity and monthly THC dose (number of joints × cannabis dose × cannabis THC concentration). Monthly THC dose only predicted follow-up dependence severity when unadjusted for baseline severity.
Cannabis users titrate their delta-9-tetrahydrocannabinol intake by inhaling lower volumes of smoke when smoking strong joints, but this does not fully compensate for the higher cannabis doses per joint when using strong cannabis. Thus, users of more potent cannabis are generally exposed to more delta-9-tetrahydrocannabinol. Smoking behaviour appears to be a stronger predictor for cannabis dependence severity than monthly delta-9-tetrahydrocannabinol dose.
大麻中 δ-9-四氢大麻酚（THC）浓度的增加可能导致更高的 THC 暴露、大麻依赖和治疗需求，但使用者也可能通过减少含有 THC 的烟雾吸入量（滴定）来调整实际的 THC 摄入量。我们调查了吸食更强效大麻的消费者每支烟卷的大麻用量或吸入的烟雾量是否少于吸食低效力大麻的消费者，以及这些因素是否预测大麻依赖严重程度。
重度大麻使用者（n=98）自带大麻，在自然环境中自由卷制一支烟卷并吸食。我们分析了烟卷的含量，其与吸烟行为的关系，以及吸烟行为与大麻依赖严重程度（DSM-IV 依赖症状总数）之间的横断面和前瞻性（1.5 年随访）关系。
大麻中 THC 浓度（范围 1.10-24.70%）与每支烟卷的大麻剂量呈正相关（b=0.008，P=0.01），但每支烟卷的 THC 浓度（范围 0.24-15.72%）与吸入量呈负相关（b=-0.05，P=0.03）。吸烟行为测量（吸烟时的吸烟量、吸入量、吸烟量减少和吸烟时的吸烟持续时间）可预测随访时的依赖严重程度，独立于基线依赖严重程度和每月 THC 剂量（烟卷数×大麻剂量×大麻 THC 浓度）。未调整基线严重程度时，每月 THC 剂量仅能预测随访时的依赖严重程度。
吸食强效烟卷的大麻使用者通过吸入较少的烟雾来调整其 δ-9-四氢大麻酚摄入量，但这并不能完全补偿每支烟卷中更高的大麻剂量。因此，吸食效力更强的大麻的使用者通常会摄入更多的 δ-9-四氢大麻酚。吸烟行为似乎比每月 δ-9-四氢大麻酚剂量更能预测大麻依赖严重程度。
