Summary: A new study shows that abstinent smokers experience heightened pain sensitivity linked to altered activity in specific brain regions. Compared to nonsmokers, abstinent smokers required more postoperative pain relief—especially opioids—and their pain sensitivity increased the longer they remained nicotine-free.
These effects appeared within a defined abstinence window, aligning with evidence that pain responses normalize after about three months. Understanding these neural mechanisms may help refine preoperative guidelines and reduce reliance on opioids in smokers preparing for surgery.
Key Facts
- Higher Pain Sensitivity: Abstinent smokers showed greater pain responses and required more postoperative analgesics.
- Brain Activity Shift: Distinct neural networks were associated with pain sensitivity and withdrawal-related care needs.
- Time-Dependent Effect: Pain sensitivity increased with abstinence but may normalize after three months.
Source: SfN
Abstinent smokers experience increased pain sensitivity during withdrawal, to the point that they often require more pain relief after surgery. Why?
New from Journal of Neuroscience, Zhijie Lu, from Fudan University Minhang Hospital, and Kai Wei, from Shanghai Eastern Hepatobiliary Surgery Hospital, led a team of researchers to explore brain activity linking nicotine withdrawal and pain sensitivity.
The researchers found that 30 abstinent smokers had altered functioning of specific brain areas, increased pain sensitivity, and a need for more postoperative pain relief—particularly with opioids—compared to 30 nonsmokers.
The longer that smokers abstained from their use, the more sensitive they were to pain, which was associated with a distinct set of brain regions.
Notably, this effect was constrained to a specific timeframe of abstinence, supporting previous findings that pain sensitivity may return to normal levels once abstinence exceeds 3 months.
The relationship between postoperative care requirements and withdrawal symptoms from abstinence was linked to a different set of brain regions.
Says Wei, “We’d like to emphasize that our study does not discourage smokers from quitting before surgery.
“Our aim is to encourage researchers to delve deeper into the mechanisms underlying elevated pain sensitivity during short-term abstinence, with the goal of developing strategies to mitigate the clinical challenge of increased analgesic (especially opioid) use associated with preoperative smoking cessation.”
The researchers have already begun exploring the mechanisms of a postoperative pain reliever that may be more effective than opioids in abstinent smokers as well as the mechanisms and effectiveness of preoperative nicotine replacement therapies.
Key Questions Answered:
A: Altered activity in specific brain regions during nicotine withdrawal heightens pain processing, increasing sensitivity.
A: No—the findings emphasize understanding and managing withdrawal-related pain, not discouraging cessation.
A: The effect is time-limited and may return to normal after roughly three months of abstinence.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this pain and neuroscience research news
Author: SfN Media
Source: SfN
Contact: SfN Media – SfN
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Altered Regional Brain Activity Underlying the Higher Postoperative Analgesic Requirements in Abstinent Smokers: A Prospective Cohort Study” by Zhijie Lu et al. Journal of Neuroscience
Abstract
Altered Regional Brain Activity Underlying the Higher Postoperative Analgesic Requirements in Abstinent Smokers: A Prospective Cohort Study
Perioperative abstinent smokers experience heightened pain sensitivity and increased postoperative analgesic requirements, likely due to nicotine withdrawal-induced hyperalgesia.
However, the underlying neural mechanisms in humans remain unclear.
To address this issue, this study enrolled 60 male patients (30 abstinent smokers and 30 nonsmokers) undergoing partial hepatectomy, collecting clinical data, smoking history, pain-related measures, and resting-state functional magnetic resonance imaging (rs-fMRI).
Compared to nonsmokers, abstinent smokers showed lower pain threshold and higher postoperative analgesic requirements.
Neuroimaging revealed altered brain function in abstinent smokers, including reduced fractional amplitude of low-frequency fluctuations (fALFF, 0.01 – 0.1 Hz) in the ventromedial prefrontal cortex (vmPFC), increased regional homogeneity (ReHo) in the left middle occipital gyrus, and decreased functional connectivity (FC) between the vmPFC to both the bilateral middle temporal gyrus and precuneus.
Preoperative pain threshold was positively correlated with abstinence duration and specific regional brain activities and connectivity. Further, the observed association between abstinent time and pain threshold was mediated by the calcarine and posterior cingulate cortex activity.
The dysfunction in vmPFC and left anterior cingulate cortex was totally mediated by the association between withdrawal symptoms and postoperative analgesic requirements.
These findings suggest that nicotine withdrawal might alter brain functional activity and contribute to hyperalgesia for the abstinent smokers.
This study provided novel insights into the supraspinal neurobiological mechanisms underlying nicotine withdrawal-induced hyperalgesia and potential therapeutic targets for postoperative pain in abstinent smokers.
