Effect of orbitofrontal lesions on mood and aggression

This chapter reviews the effects of lesions in the orbitofrontal cortex (OFC) on mood states and aggressive behavior. Particular attention is paid to studies of patients with traumatic brain injury, although data from patients with stroke or degenerative disorders are also presented. Lesions of the OFC have been observed to cause disinhibited, impulsive states that result in an increase in impulsive aggression. Problems with reduced empathy and social processing may further contribute to the clinical picture. OFC lesions are not as closely associated with depression as are dorsolateral lesions. The current literature on the effects of OFC lesions in the development of anxiety appear contradictory, with some studies showing increased and others showed decreased anxiety symptoms. Methodological issues that hinder interpretation of the effects OFC lesions on personality and mood are discussed.