Rather than an opposite dominance of the right hemisphere for negative emotions and the left hemisphere for positive emotions, there simply may be a stronger involvement of the right hemisphere for negative as compared with positive emotions. This asymmetry may be explained by assuming that some positive emotions (eg, happiness) may be better handled by the left hemisphere because these emotions can be used intentionally for functions of approach and of social communication. Whatever the mechanism, it seems that the right hemisphere is more involved than the left in control of negative emotions, and right hemisphere abnormalities contribute to some domains of psychopathology, such as affective disorders (Jaeger et al 1987; Starkstein et al 1987; Liotti et al 1991) and content-specific delusions (Feinberg 1999). Further, there is evidence of possible premorbid bilateral- and right-frontal abnormalities in individuals at risk for alcoholism, a subset of whom display impulsivity, insensitivity to reinforcement, antisocial personality disorder, etc (Tarter et al 1985; Hesselbrock 1991; Pihl and Peterson 1991; Lappalainen et al 1998).
