Independent contributions of social cognition and depression to functional status after moderate or severe traumatic brain injury

Impairments in cognitive processing related to social understanding and communication (i.e., "social cognition") are well documented after moderate or severe traumatic brain injury (TBI) and can contribute to negative functional outcome. Depression is also a common feature of TBI with detrimental functional consequences. We evaluated relationships between social cognition, depression symptom severity, and functional status in individuals with chronic TBI (>1 year post injury; n = 25) and healthy controls (n = 30) using objective tests of social cognition as well as self-reported depression (Beck Depression Inventory-II) and functional status (Functional Behavior Profile). Results revealed significant relationships between depression and functional status across the sample, and relationships between social cognition and functional status specific to TBI. In the TBI group only, social cognition significantly predicted both overall and social functional status above and beyond depression. Group differences in functional status were independently mediated by social cognition and, especially, depression. Our findings suggest that social cognitive impairments and depression are distinct, functionally relevant TBI sequelae. Interventions to improve social functioning in this population may be most effective when contextualized within treatments for emotional disturbances.