OBJECTIVES: The purpose of this study was to apply Weiner's (1986) attributional model of helping to the care of clients presenting with challenging behaviour. A number of predictions were tested: (a) that aggressive, destructive, and self-injurious behaviours would differentially affect carers' ratings of attributional dimensions; (b) that carers' propensity to help would be mediated by positive affect rather than optimism; (c) that optimism would be reduced by a perceived stable cause, such as client's level of dependency.