Impact of nicotine, cannabis, co-use and non-use on single day morning and evening cortisol and subjective state: During ambulatory assessment

Nicotine and cannabis are commonly used substances that impact overall health. With increasing reports of nicotine and cannabis co-use, additional challenges arise for programs aimed at addressing cessation. This study examined the independent and additive effects of substance use on adrenocortical and psychological measures in nicotine users, cannabis users, co-users and non-users. Across two separate 3-day ambulatory monitoring assessments, one of which was during ad-libitum substance use and the other following a period of substance abstinence, 116 healthy adults were asked to complete mood state questionnaires and to collect saliva for cortisol measurement four times each day. Results showed that nicotine users overall had higher cortisol levels compared to co-users and non-users and exhibited smaller differences between morning and evening cortisol compared to non-users. Co-users reported lower levels of positive affect, an earlier age of onset for both cannabis use and nicotine use, and a higher daily intake of and more severe dependence on cannabis compared to cannabis users. Given these observed differences between substance use groups, future research is warranted to examine the role of co-use in cessation success.