Morning Bright Light Treatment for Chronic Low Back Pain: Potential Impact on the Volatility of Pain, Mood, Function, and Sleep

Objectives Most treatment outcome studies for people with chronic low back pain (CLBP) have based analyses on and reported only the mean levels of these factors. However, high levels of pain, mood, function, and sleep volatility may represent unique factors contributing to diminished quality of life. Our goal was to determine whether bright light treatment affected both mean levels of pain, mood, function, and sleep and reduced volatility in these outcomes. Methods US military veterans with CLBP (N = 22) underwent an open trial with a seven-day baseline, followed by 13 days of a one-hour morning bright light treatment self-administered at their home and a 30-day follow-up. Participants completed daily diary measures at 12 Pm and 6 Pm every day during the three study epochs. Results Using location scale modeling, results suggested that, in addition to being associated with changes in mean levels of pain intensity, pain interference, negative affect, and sleep quality, bright light treatment was also related to reductions in the volatility of pain intensity and negative affect, reductions that were largely maintained during follow-up. Conclusions Changes in mean levels and volatility were independent factors, suggesting that bright light treatment was related to participants experiencing fewer “pain flares.” These findings underscore the potential importance of volatility as a future treatment target.