I have a hunch that there are bidirectional processes between mother and infant that are organized around the second year, related to maternal concerns of behaviour problems in their kids, that may mediate later outcome.
I have worked with Achenbach scales (CBCL) on 2-5 and 6-14 years in children with chronic illness. Attention deficit and aggressive behavior were commonly observed. But have not worked for the effect of maternal concern upon the mental health of the child.
I would be interested in know how the measure behaves with this age group (24 months). If you have something descriptive or something more formally written up, I would be interested in reading. Thanks for your response.