A prospective examination of Axis I psychiatric disorders in the first 5 years following moderate to severe traumatic brain injury.

BACKGROUND

Psychiatric disorders commonly emerge during the first year following traumatic brain injury (TBI). However, it is not clear whether these disorders soon remit or persist for long periods post-injury. This study aimed to examine, prospectively: (1) the frequency, (2) patterns of co-morbidity, (3) trajectory, and (4) risk factors for psychiatric disorders during the first 5 years following TBI.

METHOD

Participants were 161 individuals (78.3% male) with moderate (31.2%) or severe (68.8%) TBI. Psychiatric disorders were diagnosed using the Structured Clinical Interview for DSM-IV, administered soon after injury and 3, 6 and 12 months, and 2, 3, 4 and 5 years post-injury. Disorder frequencies and generalized estimating equations were used to identify temporal relationships and risk factors.

RESULTS

In the first 5 years post-injury, 75.2% received a psychiatric diagnosis, commonly emerging within the first year (77.7%). Anxiety, mood and substance-use disorders were the most common diagnostic classes, often presenting co-morbidly. Many (56.5%) experienced a novel diagnostic class not present prior to injury. Disorder frequency ranged between 61.8 and 35.6% over time, decreasing by 27% [odds ratio (OR) 0.73, 95% confidence interval (CI) 0.65-0.83] with each year post-injury. Anxiety disorders declined significantly over time (OR 0.73, 95% CI 0.63-0.84), whilst mood and substance-use disorder rates remained stable. The strongest predictors of post-injury disorder were pre-injury disorder (OR 2.44, 95% CI 1.41-4.25) and accident-related limb injury (OR 1.78, 95% CI 1.03-3.07).

CONCLUSIONS

Findings suggest the first year post-injury is a critical period for the emergence of psychiatric disorders. Disorder frequency declines thereafter, with anxiety disorders showing greater resolution than mood and substance-use disorders.