By NICHOLAS BAKALAR
A new study has found that among immigrants, younger age at the time of migration predicts a higher incidence of psychotic disorders.
The study, published in December in The American Journal of Psychiatry, was conducted from 1997 to 2005 in The Hague, where there are detailed records on almost everyone ages 15 to 54 who has made contact with the health care system for a possible psychotic disorder. The researchers found 273 immigrants, 119 second-generation citizens and 226 Dutch citizens who fit the criteria.
In four ethnic groups — people from Suriname, the Netherlands Antilles, Turkey and Morocco — the risk of psychosis was most elevated among those who immigrated before age 4. There was no association of psychosis with age among immigrants from Western countries.
The researchers, led by Dr. Wim Veling of the Parnassia Psychiatric Institute in The Hague, investigated various possible explanations — that social factors may be involved, that people may migrate because they are prone to psychosis, that a decision to migrate is influenced by the early appearance of psychosis, among many others. But the correlation between younger age of migration and the development of psychosis persisted.
“We don’t know the reason,” said Dr. Ezra Susser, the senior author and a professor of epidemiology at Columbia University, “but it might be related to early social context, which we know has an important influence on later health and mental health.”
