Ford et al (Reference Ford, Vastanis and Meltzer2007) investigated the possible explanations for the increased prevalence of psychiatric disorder in children looked after by local authorities and linked looked after status with higher levels of psychopathology, educational difficulties and neurodevelopmental disorders. They suggested that services should bear in mind that a change of environment might be appropriate in providing help, at least in some cases.

After carefully reading the article, I think that Ford et al have missed an important aetiological factor: the influence of genetics. Studies (e.g. Reference Howard, Kumar and ThornicroftHoward et al, 2001) have shown that children of parents with mental disorder are likely to be looked after by another person or organisation. Biological factors which caused mental illness in the parents of children currently looked after by services might operate to cause the increased prevalence of psychiatric disorder in these children. Hence by neglecting the biological component of the bio-psychosocial model of mental illnesses, Ford et al have failed to provide a comprehensive assessment of causative factors in these children.

The authors could have included psychiatric disorder in the parents as a variable and divided the looked after group into children of parents with or without mental disorder. Ford et al have identified that neurodevelopmental disorders and learning difficulties are associated with increased prevalence of psychiatric disorder. Both are also associated with the future development of mental illnesses such as schizophrenia (Reference Done, Crow and JohnstoneDone et al, 1994; Reference Lawrie, Byrne and MillerLawrie et al, 2001) in which genetic factors play an important aetiological role (Reference Cardno, Marshall and CoidCardno et al, 1999).