Tags:  Stress reactivity, psychosocial stress, cardiovascular response, craving, cannabis

  

The problem: Physiological responses to acute stress is regulated by the body’s endocannabinoid system. This system regulates many functions in the body, including memory, mood and immunity; it is also considered to be a key player in maintaining homeostasis, which refers to the ability to maintain a relatively stable internal state despite changes that happen in the external world. The endocannabinoid system is also the target of two key components of cannabis- namely cannabidiol (CBD) and D-9-tetrahydrocannabinol (THC). Therefore, it is important to understand the potential implications of long-term cannabis use on acute stress response.

 

The study: This study examined the impact of regular cannabis use on cardiovascular and subjective responses to acute stress.

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Main results: A total of 79 participants (45 cannabis users, 34 non-cannabis users) were included in this study.

• Participants completed a laboratory visit that was designed as follows: rest period 1, three acute stress tasks (speech delivery, mental math, cold-pressor test), followed by rest period 2.

  • Subjective states (state stress, positive affect, state anxiety, cannabis craving) were measured at 4 time points (before and after rest period 1, after the stress tasks, and after rest period 2).

  • Cardiovascular data (blood pressure, heart rate, mean arterial pressure) data were assessed at 5 time points (every 5 minutes during rest period 1, every 2 minutes during the stress tasks, and every 5 minutes during rest period 2).  

• Regular cannabis use was significantly associated with blunted positive affect, state stress, and state anxiety in response to acute stress challenges.

• Cannabis use was not associated with changes in cardiovascular responses.

• Cannabis craving significantly decreased in response to stress challenges.

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Conclusions: Chronic cannabis use is associated with blunted positive and negative emotional responses to acute stress.

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Why this is a good study:

• Cannabis users were identified using fairly strict selection criteria, and cannabis use was confirmed biochemically using a urine test.

• This is a strong study because the authors measured emotional/ cardiovascular responses at multiple time points before, during and after acute stress. This allowed the measurement of temporal responses to acute stress.

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Why this isn’t a perfect study:

• The two groups of participants were not completely balanced: non-cannabis users were older than the cannabis users (mean age: 38 vs. 30 years), and nicotine use was ~3-times higher among cannabis users. These factors may have affected the outcomes observed in this study.

• The study found no association between cannabis use and cardiovascular outcomes. However, it is likely that cannabis use affects other cardiovascular outcomes that were not measured in this study.

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What this study adds:

• The study shows that regular cannabis use is significantly associated with blunted emotional responses to acute stress. However, there was no impact of cannabis use on cardiovascular outcomes measured in this study.

• Contrary to expectations, the study also showed acute stress did not increase cannabis craving.

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What it doesn’t:

• Due to the study design, one cannot determine whether the blunted responses to acute stress that was observed among cannabis users are a direct effect of the cannabis or due to pre-existing differences among these participants.

• Due to the relatively small sample size, the analysis was not powered to determine potential gender-specific differences in acute cardiovascular effects of cannabis.

• Additionally, the authors obtained data from heavy cannabis users (15 days/month for ≥1 year). The impact of mild cannabis use on emotional and cardiovascular responses were not analyzed.

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Funder: This research was supported, in part, by grants from the National Institutes of Health.

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Author conflicts: None