The neuropsychiatry of pathologic affect: an approach to evaluation and treatment.

The ability to skillfully regulate the internal experience and outward expression of emotion is among the most complex and recently acquired functions of the human brain. When the capacity for emotional regulation is compromised by disease or injury the impact on individuals and their families may be considerable, both with regard to psychological well-being and social and occupational function. This article describes first a framework for the description, evaluation, and treatment of affective dysregulation. We review the literature regarding disorders of affective regulation, and in particular affective lability. Although disorders of affect as they occur in common neuropsychiatric disorders (eg, stroke, multiple sclerosis, traumatic brain injury, and so on) are the focus of this article, the review incorporates information from the study of patients with primary psychiatric disorders and hence the discussion herein may also be relevant to the understanding and treatment of affective lability in these conditions. An overview of the neurobiology that appears most relevant to understanding such problems is presented, along with several specific methods that appear to be useful in the evaluation of patients with affective lability. Finally, we review the literature regarding the treatment of disorders of affect and offer some practical suggestions for the treatment of patients with these problems.