“…Two nurse rating scales [51,52] have been published, but are only suitable for hospital use, and do not have the precise measurements obtained by videotape analysis or ethological techniques. For 30 years, filming of mother-infant interaction during play or feeding has been used to study mother-infant interaction, and 5- to 15-min videotapes have become standard for this research [53,54,55,56,57,58,59,60,61]. So far, little attempt has been made to discriminate, in these brief behavioural samples, between impairment due to depression, obsessions of child harm or child-focused anxiety and impairment due to aversion to the infant, although Clark [62] has shown, by a state-of-the-art factor analysis in a large sample of mothers with 12-month-old children, that a measure of anger and negative affect can be obtained from a study of 5-min play.…”