Multimodal examination of daily stress rhythms in chronic Cannabis users.

Rationale: Chronic cannabis users frequently report stress relief as their primary reason for use. The endocannabinoid system is involved in the neuroendocrine stress response, and diurnal cortisol rhythms may be disrupted in chronic cannabis users.

Objectives: The objectives were to determine whether cannabis users demonstrate disruptions in diurnal stress rhythms and examine the acute effects of cannabis on stress-related outcomes in cannabis users' natural environments.

Methods: Eighty-two participants (39 cannabis users, 43 non-users) collected saliva samples to quantify cortisol concentrations and provided subjective stress ratings at 8 time points throughout the day. They wore a medical-grade wearable device for 24 h that recorded physiological indicators of stress (heart rate variability, electrodermal activity). Cannabis users collected additional saliva samples before and after cannabis use to examine acute effects of cannabis use.

Results: Cannabis users exhibited significant dysregulations in diurnal cortisol rhythms, including a blunted cortisol awakening response, flattened diurnal cortisol slope, and elevated afternoon cortisol concentrations. There were no differences in diurnal heart rate variability or electrodermal activity except for elevated evening heart rate in cannabis users. Finally, there were significant decreases in cortisol, subjective stress, and electrodermal activity following acute cannabis use in cannabis users' natural environment.

Conclusions: These results provide evidence of dysregulated diurnal cortisol rhythms in cannabis users that were related to later waking times and acute stress-relieving properties of cannabis use in naturalistic environments. Future research should examine the direction of the relationship between cannabis use and diurnal cortisol rhythms and potential implications for other psychological disorders.