The clinical significance of major depression following mild traumatic brain injury
Rapoport MJ, McCullagh S, Streiner D and Feinstein A;
Commented by , 29 Jan 2003
Background
Major depression following traumatic brain injury (TBI) is common, and has been associated with poor psychosocial functioning. Previous studies, however, have not focussed on patients with mild TBI, rather involved moderate to severe or heterogeneous TBI populations.
Poor psychosocial outcome has been found in 15-20% of mild TBI patients; the extent to which this is associated with major depression remains unclear.
Purpose
To assess the association between major depression and a number of neurobehavioral and functional outcomes following mild TBI.
Methods
Consecutive patients with mild TBI (loss or alteration of consciousness < 30 minutes, initial Glasgow Coma Score of 13-15, posttraumatic amnesia < 24 hours) attending their first follow-up appointment at a tertiary care TBI clinic were assessed.
Premorbid focal brain disease, acute medical illness, or previous history of dementia, schizophrenia or mood disorder (N=41) led to exclusion. Demographic and head injury data were collected. All patients (N=170) were evaluated by a psychiatrist for the presence of a major depressive episode (MDE), using the Structured Clinical Interview for DSM-IV (SCID).
Subjective psychosocial outcome, psychological distress and postconcussive symptoms were measured by the Rivermead Head Injury Follow-up Questionnaire, General Health Questionnaire and Rivermead Post Concussion Symptoms Questionnaire, respectively.
Objective measures of outcome included the Glasgow Outcome Scale (global functioning) and the Neurobehavioral Rating Scale-Revised. Patients with and without major depression were compared on categorical demographic, injury and outcome variables using chi-square analysis.
Between group continuous outcome variables were compared by analysis of variance, and covariance in the case of demographic and injury mismatch.
Results
Subjects were 50% male with a mean age of 44.2 years, seen at a mean of 48.4 days post-injury. 26 (15.3%) of 170 patients met criteria for major depression.
Subjectively, patients with major depression reported higher levels of psychosocial impairment, psychological distress and symptoms of postconcussive disorder versus those without (P<0.0001).
Objectively, major depression was associated with significantly greater neurobehavioral disturbance. While patients with major depression had worse objective functional outcome than those without (19.2% versus 36.8% with good outcome), this did not reach significance.
Discussion
In a sample restricted to mild TBI, this study demonstrates that major depression in the acute period is associated with poor subjective and objective outcomes across multiple domains. An important contribution, as previously this association had been limited to moderate to severe or heterogeneous TBI populations, less common in prevalence.
This study raises the importance of prompt evaluation and treatment of major depression in this population of “milder” TBI patients.
The strengths of the study include the exclusion of patients with premorbid mood disorder, the use of a structured clinical interview by a psychiatrist for the diagnosis of depression, and a range of subjective and objective outcome measures.
The major limitation is the cross-sectional nature of the design, on average approximately 6 weeks post-injury. Potential sources of bias include a referral bias from a tertiary care TBI clinic, possibly involving a more symptomatic group of patients.
Furthermore, while psychiatrist raters of objective measures were blind to subjective outcomes, they were not blind to the results of the SCID.