Prevalence, natural course and predictors of depression 1 year following traumatic brain injury from a population-based study in New Zealand

Objective: Depression is common post-TBI, yet has not been studied longitudinally, nor at a population level. This study examined prevalence of depression in a population-based sample across the first year post-TBI. Design and methods: Prospective follow-up of 315 adults (>16 years) with assessments (Hospital Anxiety Depression Scale, DSM-IV criteria) at 1-, 6- and 12-months post-TBI. Demographic and injury-related predictors of depression at 1-year post-TBI were also explored. Results: The number of individuals identified as depressed reduced significantly between baseline and 12-months post-TBI from 21-12.4% using the HADS and 49-34% using DSM-IV criteria; with only 10 of the 28 individuals initially meeting criteria on the HADS continuing to do so at 12-month follow-up. Meeting HADS depression criteria was linked to pre-morbid depression and/or anxiety; while those meeting DSM-IV criteria were older, but not significantly so. Conclusions: The findings suggest depression is common post-TBI and that clinicians/researchers use caution in its diagnosis, as existing criteria have significant overlap with common TBI sequels.