Adolescent pain: appraisal of the construct and trajectory prediction-by-symptom between age 12 and 17 years in a Canadian twin birth cohort.

Adolescent pain is common and continues into adulthood, leading to negative long-term outcomes including substance-related morbidity: an empirical definition of its construct may inform the early detection of persistent pain trajectories. These secondary analyses of a classical twin study assessed whether headaches, back pains, abdominal pain, chest pains, stabbing/throbbing pain, and gastric pain/nausea, measured in 501 pairs across 5 waves between age 12 and 17 years, fit a unitary construct or constitute independent manifestations. We then assessed which symptoms were associated with a steady, "frequent pain" trajectory that is associated with risk for early opioid prescriptions. Item response theory results indicated that all 6 pain symptoms index a unitary construct. Binary logistic regressions identified "back pain" as the only symptom consistently associated with membership in the "frequent adolescent pain" trajectory (odds ratio: 1.66-3.38) at all 5 measurement waves. Receiver operating characteristic analyses computed the discriminating power of symptoms to determine participants' membership into the "frequent" trajectory: they yielded acceptable (0.7-0.8) to excellent (0.8-0.9) area under the curve values for all 6 symptoms. The highest area under the curve was attained by "back pain" at age 14 years (0.835); for multiple cut-off thresholds of symptom frequency, "back pain" showed good sensitivity/false alarm probability trade-offs, predominantly in the 13 to 15 years age range, to predict the "frequent pain" trajectory. These data support a unitary conceptualization and assessment of adolescent pain, which is advantageous for epidemiological, clinical, and translational purposes. Persistent back pain constitutes a sensitive indicator of a steady trajectory of adolescent pain.