This study analyzes the interaction patterns and behavioral characteristics of mentally ill and well mothers and their young children. The children were between 1 and 4 years of age. The group of mentally ill mothers was comprised of 18 schizophrenic and psychotically depressed women each with a history of at least one psychiatric hospitalization. The well mothers were matched with two experimental groups (one receiving treatment in the home and the other receiving treatment in a special clinic program) on six variables: age and sex of youngest child, mothers age and marital status, race and socioeconomic status. The data were obtained--prior to intervention--from behavioral analyses of 72 five-minute videotaped sequences of feeding and unstructured play of each mother-child pair. Significant differences between the well and mentally ill mothers were found in only six of the 25 feeding categories and six of the 25 unstructured play categories. Only two of these 12 variables were significant in both feeding and unstructured play: consistency of maternal behavior over 5 minute segment, and amount of contact (touching, holding, gazing). The most significant difference between groups was found on the dyadic variable of reciprocity during feeding. The dyadic interaction of the mentally ill mothers and their children was characterized by fewer attempts by the mother to understand the child or to respond to the child's cues. (Author/SS)