In a randomized trial, more than 100 healthy individuals were assigned to an 8-week mindfulness-based stress reduction (MBSR) program, a health improvement program (HEP) of the same length, or a waiting list.
Scanning participants’ brains during a heat-based stimulus pain task showed those who completed the MBSR had a reduction in a brain signature linked to the sensory intensity of pain.
Dr. Joseph Wielgosz
“Our finding supports the idea that for new practitioners, mindfulness training directly affects how sensory signals from the body are converted into a brain response,” lead investigator Joseph Wielgosz, PhD, of the Center for Healthy Minds, University of Wisconsin–Madison, said in a release.
Further analysis in long-term meditation practitioners showed the total time spent on intensive retreats was associated with neural changes associated with the perceived stress of pain.
“Just like an experienced athlete plays a sport differently than a first-timer, experienced mindfulness practitioners seem to use their mental ‘muscles’ differently in response to pain than first-time meditators,” Dr. Wielgosz noted.
The findings were published online in the American Journal of Psychiatry.
A complex condition
Dr. Wielgosz told this news organization that pain is “complex,” with multiple stages and several phases between the time signals are sent from pain receptors and the experience of pain.
“The way that mindfulness affects pain processing has more to do with the way the brain interprets pain signals.”
The investigators note that understanding the neurocognitive mechanisms underlying the efficacy of nonpharmacologic pain interventions is a “high-priority objective for improving pain treatment.”
Evidence from brief laboratory interventions and cross-sectional studies suggests that mindfulness training is associated with alterations in both sensory processing and cognitive-emotional regulatory networks, the investigators note.
“However, no such study has yet been conducted on a standardized, full-length, and widely used clinical intervention, such as MBSR,” they add.
Thermal pain task
The randomized, active-control trial included 115 healthy, meditation-naive individuals (61.7% women; average age, 48.3 years). Just over half (58%) had a graduate degree and their mean score on the Hollingshead index was 58.3, indicting a higher socioeconomic status.
All were randomly assigned to an 8-week MBSR course, an 8-week HEP course as an active control group, or a waiting-list control group with no intervention.
The MBSR involved instruction and practice in continuous focused attention on the breath, bodily sensations, and mental content while in seated postures, walking, and doing yoga.
The HEP matched the MBSR in terms of its length, structure, and nonspecific therapeutic elements, which included a supportive group atmosphere, expert instruction, and positive expectancy for benefit.
To examine the interventions’ effect on the pain experience, participants underwent a pain task in which they had 20 thermal stimuli applied to the inside of the left wrist for 12 seconds, including 8 seconds at peak temperature.
The stimuli were separated by a distractor task and intervals for cued anticipation, recovery, and subjective ratings of intensity and unpleasantness on a scale of 0-20.
During the task, participants underwent MRI to assess the neurologic pain signature (NPS) and the stimulus intensity independent pain signature-1 (SIIPS-1) within the brain.
The NPS is activated by various types of pain stimuli, while responding minimally or not at all to “emotionally evocative stimuli” relating to pain or to placebo treatment, the researchers note.
In contrast, the SIIPS-1 is activated in response to aspects of pain unrelated to the stimulus itself. It incorporates a “broader range of cognitive and emotional modulatory circuits,” including those related to expectancy and cognitive processes to modulate the pain experience.