Authors' reply

Dr Chaturvedi questions the clinical relevance of knowing that offspring of mothers with schizophrenia are at increased risk of developing both psychotic and non-psychotic disorders, particularly because preventive measures are not available. However, preventive measures may be available in the future. Clinical high-risk studies already suggest that using specific preventive interventions, it is possible at least to delay the onset of psychosis in patients at incipient risk of psychosis (McGorry et al, 2002). However, the criteria for being clinically at high risk require that the individual is already showing psychotic-like symptoms or impaired functioning (McGorry et al, 2002). One of the goals in high-risk studies (including ours) is to identify early indicators of emerging psychotic disorders that could be detected before any impairment starts to develop.

Family interventions are rarely targeted at children of mothers with psychotic disorders, who often remain uninformed about their parent's illness and have to cope alone with their parent's symptoms and take additional responsibility for the family (Valiakalayil et al, 2004). We hope that the knowledge that the children are themselves at increased risk of developing mental disorders will enhance the planning and implementation of supportive measures and parental education for families where the parent(s) suffer from psychotic disorder. Such support should begin during pregnancy and continue through childhood and adolescence. These measures could also turn out to be preventive: the Finnish Adoption Study showed that the risk of developing schizophrenia-spectrum disorders among adoptees whose biological mothers had schizophrenia was much lower if they were raised in adoptive families with ‘healthy’ rearing patterns (Tienari et al, 2004).

Finally, Dr Chaturvedi suggests that there might be a genuine decline in the risk of developing schizophrenia among high-risk children. We discussed this possibility in our article, but the method of identifying the mothers in our study differs so much from those of the Copenhagen and New York high-risk studies that we still consider it premature to draw such a conclusion.