Changes in somatic and non-somatic depressive symptoms between inpatient rehabilitation and follow-up

Background: We identified changes in depressive symptoms, as measured by the Patient Health Questionnaire-9 (PHQ-9), between inpatient rehabilitation and at one year post-discharge after spinal cord injury (SCI).

Design: Inpatient interview data were collected at a large rehabilitation hospital in the Southeastern United States. Survey methodology was used at one year follow-up.

Methods: Inclusion criteria included: (a) traumatic SCI, (b) hospitalized for inpatient rehabilitation, and (c) at least 16 years of age. 568 participants completed the preliminary interview. One year after discharge, 219 completed the PHQ-9, a screening measure of major depressive disorders. We performed cross-lag regression between times of measurement for somatic and non-somatic factors (identified using confirmatory factor analysis at baseline).

Results: A significantly greater portion of individuals were at the extremes at follow-up (27%) compared with inpatient rehabilitation (17%). The non-somatic factor (i.e., all except fatigue, appetite, sleep) from inpatient was significantly predictive of both the non-somatic (r=.35, p<.001) and somatic factors at follow-up (r=.40, p<.001). In contrast, the somatic factor did not significantly predict either the somatic (r=.13, ns) or non-somatic factors at follow-up (r=.07, ns).

Conclusions: 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. Only non-somatic items from inpatient assessments should be used in the prediction of future depressive symptoms. Clinicians should also be aware that depressive symptoms do not appear to differentiate into either extreme until after inpatient rehabilitation.