Divergent manifestations of irritability in patients with mild and moderate-to-severe traumatic brain injury: Perspectives of awareness and neurocognitive correlates

Primary objectives: To evaluate irritability in patients with mild traumatic brain injury (mTBI) and moderate-to-severe traumatic brain injury (msTBI), respectively. Research design: A prospective study was conducted at a level I trauma centre. Methods and procedures: A total of 160 participants, which included 80 healthy subjects and 80 patients with TBI, were recruited. Irritability was assessed by the National Taiwan University Irritability Scale and other cognitive functions, which included memory, executive function and information processing, were also evaluated. Main outcomes and results: The results showed post-injury self-reported irritability in patients with mTBI and family-reported irritability in patients with msTBI were significantly higher than irritability reported by healthy participants. Irritability was significantly associated with information processing ability in patients with mTBI, but it was not associated with any cognitive functions in patients with msTBI. Conclusions: Irritability was found to be prominent after TBI. Divergent causes of irritability seemed apparent in patients with mTBI and msTBI. Irritability after mTBI appeared might be related to the cognitive functions disrupted after the injury, whereas irritability after msTBI appeared to result directly from the brain lesions involved.