Amitriptyline and chronic low-back pain. A randomized double-blind crossover study

The effect of antidepressant medication on chronic low-back pain patients was studied in a randomized blind crossover study. Among those patients who completed the study, there was a 46% decrease in the use of analgesics while on amitriptyline when compared to placebo (P less than 0.005). There was also improvement in affect, but no measurable change in activity level. The MMPI profile of those patients who were unable to comply with the study protocol differed from that of patients who completed the study. The noncompliers demonstrated an elevation of the F, Pd, Pt (P less than 0.05) and Mf (P less than 0.01) scales. Although the interpretation of such a profile is left open to speculation, it may serve as an indicator of noncompliant individuals.