Objective: The impact of mental health on disease burden associated with injury represents a major public health issue, yet almost no information is available on the associated long-term mental health outcomes. The primary aim of this study was to assess the psychiatric outcomes 6 years after a severe injury and their subsequent impact on long-term disability. The secondary aim was to investigate the relationship between a mild traumatic brain injury (mTBI) and long-term psychiatric disorder and its impact on disability.

Methods: From April 2004 to February 2006, randomly selected injury patients admitted to 4 hospitals across Australia were assessed during hospitalization and at 72 months after trauma (N = 592). Injury characteristics, the presence of an mTBI (ICD-9 criteria), and previous psychiatric history were assessed during hospitalization. Structured clinical interviews for psychiatric disorders (DSM-IV and DSM-5) and a self-report measure of disability (WHODAS II) were administered at 72 months.

Results: At 72 months after a severe injury, 28% of patients met criteria for at least 1 psychiatric disorder, with 45% of those presenting with comorbid diagnoses. The most prevalent psychiatric disorder was a major depressive episode (11%) followed by substance use disorder (9%), agoraphobia (9%), posttraumatic stress disorder (6%), and generalized anxiety disorder (6%). The presence of any psychiatric disorder was found to increase the risk for disability (P < .001, odds ratio = 6.04). An mTBI was found to increase the risk for having some anxiety disorders but not to increase disability by itself.

Conclusions: The long-term psychiatric consequences of severe injury are substantial and represent a significant contributor to long-term disability. This study points to an important intersection between injury and psychiatric disorder as a leading contributor to disease burden and suggests this growing burden will impose new challenges on health systems.