Features Research
Butt out: How cigarette smoking can be a pain in the back

“Smoking affects the brain,” said the study’s lead author, Bogdan Petre,
in an article posted on Northwestern University’s website.

“We found that it affects the way the brain responds to back pain and
seems to make individuals less resilient to an episode of pain,” added
Petre, who is also a technical scientist at Northwestern University
Feinberg School of Medicine.

The study was published online in the journal Human Brain Mapping.
According to Northwestern University, this study is the first evidence
linking smoking and chronic pain with the part of the brain associated
with addiction and reward.

The involved a longitudinal observational study of 160 adults with new
cases of back pain. At five different times throughout the course of a
year they were given MRI brain scans and were asked to rate the
intensity of their back pain and fill out a questionnaire which asked
about smoking status and other health issues. Thirty-five healthy
control participants and 32 participants with chronic back pain were
similarly monitored.

MRI activity between two brain areas (nucleus accumbens and medial
prefrontal cortex, NAc-mPFC) was analyzed. These brain areas are
involved in addictive behavior and motivated learning. This circuitry is
critical in development of chronic pain, the scientists found.

These two regions of the brain “talk” to one another and scientists
discovered that the strength of that connection helps determine who will
become a chronic pain patient, the Northwestern University article
stated. By showing how a part of the brain involved in motivated
learning allows tobacco addiction to interface with pain chronification,
the findings hint at a potentially more general link between addiction
and pain.

“That circuit was very strong and active in the brains of smokers,”
Petre said. “But we saw a dramatic drop in this circuit’s activity in
smokers who ¬– of their own will – quit smoking during the study, so
when they stopped smoking, their vulnerably to chronic pain also
decreased.”

Medication, such as anti-inflammatory drugs, did help study participants
manage pain, but it didn’t change the activity of the brain circuitry.
In the future, behavioural interventions, such as smoking cessation
programs, could be used to manipulate brain mechanisms as an effective
strategy for chronic pain prevention and relief, the report said.

The U.S. National Institutes of Neurological Disorders and Stroke funded the study.

Other authors of the paper are senior author Apkar Vania Apkarian,
Souraya Torbey, James W. Griffith, Gildasio De Oliveira, Kristine
Herrmann, Ali Mansour, Alex T. Baria, Marwan N. Baliki and Thomas J.
Schnitzer of Northwestern University Feinberg School of Medicine.