It is demonstrated first that staff explanations of problem behaviour can be reliably coded using a modified form of the Attributional Style Questionnaire; and second, that staff explanations are related through staff optimism to anticipated helping behaviour. This supports the hypothesis that, in professional staff, an important determinant of helping is optimism arising from attributions of a patient's problems. The influence of affective judgements, as emphasized in Weiner's (1986) theory of helping behaviour, is not supported.