Persons with brain injuries demonstrate an inconsistency in functioning over time and circumstances that requires a consideration of factors in addition to the size and location of the acquired brain lesions. A multi-factor account is presented in which neuropsychological disability on any occasion is attributed to some combination of neuropsychological deficits plus one or more of four personal factors (negative thinking, tension-arousal, fatigue, physical symptoms) and three situational factors (demands for complex attention, demands for rapid processing, external distractions). Citing pertinent research the paper discusses the development of, and possible mechanisms of influence by, these seven factors. It then broadly prescribes clinical interventions that might assist clients to reduce their adverse effects. It is suggested that the scope of brain injury rehabilitation be extended to include training clients to identify and manage non-organic conditions that may combine with direct brain injury effects to compromise productive work, complicate social relationships, or render the affected person less able to cope with stress.