Prediction of somatic and non-somatic depressive symptoms between inpatient rehabilitation and follow-up.
Longitudinal. We identified changes in the association of somatic and non-somatic symptoms (as measured by the Patient Health Questionnaire-9, PHQ-9) between inpatient rehabilitation after spinal cord injury (SCI) and 1 year after discharge. A specialty hospital in the Southeastern USA. A total of 584 adults with traumatic SCI were administered the PHQ-9 during inpatient rehabilitation. Of them, 227 completed the PHQ-9 by survey at 1-year follow-up. We performed time-lagged regression between times of measurement for somatic and non-somatic factors of the PHQ-9. The non-somatic factor at baseline was significantly predictive of the non-somatic (r=0.67, P=0.002) and somatic factors at follow-up (r=0.53, P=0.019). The somatic factor did not significantly predict either the somatic (r=0.10, n.s.) or non-somatic factors at follow-up (r=-0.01, NS). Factor analysis also indicated changing factor structure between inpatient rehabilitation and follow-up. Our results question the interpretation of somatic items during inpatient rehabilitation, as they are not predictive of either somatic or non-somatic symptoms at follow-up.