Background: Psychiatric disorders are common following traumatic brain injury (TBI). However, few studies have examined the course of disorder development and the influence of pre-injury psychiatric history. The present study aimed to examine the frequency of, and association between, psychiatric disorders occurring pre- and post-injury, and to examine the post-injury course of disorders.
Method: Participants were 102 adults (75.5% male) with predominantly moderate-severe TBI. Participants were initially assessed for pre-injury and current disorders, and reassessed at 3, 6 and 12 months post-injury using the Structured Clinical Interview for DSM-IV Disorders (SCID).
Results: Over half of the participants had a pre-injury psychiatric disorder; predominantly substance use, mood, and anxiety disorders. In the first year post-injury, 60.8% of participants had a psychiatric disorder, commonly anxiety and mood disorders. Post-injury disorders were associated with the presence of a pre-injury history (p<0.01), with 74.5% of participants with a pre-injury psychiatric history experiencing a post-injury disorder, which commonly presented at initial assessment or in the first 6 months. However, 45.8% of participants without a pre-injury history developed a novel post-injury disorder, which was less likely to emerge at the initial assessment and generally developed later in the year.
Conclusions: Despite evidence that most post-injury psychiatric disorders represent the continuation of pre-existing disorders, a significant number of participants developed novel psychiatric disorders. This study demonstrates that the timing of onset may differ according to pre-injury history. There seem to be different trajectories for anxiety and depressive disorders. This research has important implications for identifying the time individuals are most at risk of psychiatric disorders post-injury.