Moving during childhood linked to increased schizophrenia risk

By Laura Cowen, medwireNews Reporter

Childhood residential mobility is associated with an increased risk of psychotic disorders, particularly schizophrenia, during adulthood, according to results of a study conducted in Denmark.

Children who move several times and those who move during adolescence may be particularly vulnerable, report Diana Paksarian (National Institute of Mental Health, Bethesda, Maryland, USA) and colleagues in Schizophrenia Bulletin.

The researchers explain that residential mobility during childhood is a potential form of adversity that could impact psychosis risk by disrupting “the continuity of children’s psychosocial contexts, challenging them to navigate new and unfamiliar neighborhoods, schools, and peer groups.”

Using data from the Danish Civil Registration System, the team calculated the number of moves between any of the 276 Danish municipalities during each year from birth to age 15 years for approximately 1.1 million individuals born between 1971 and 1991. The individuals were then followed up from age 15 to development of a psychotic disorder, death, emigration from Denmark, or until December 2010 when they were between 19 and 39 years old.

During the follow-up period there were 7277 cases of narrowly defined schizophrenia, 12,970 of broadly defined schizophrenia and 2841 cases of bipolar disorder. Mobility was highest in the year of birth and declined across childhood.

Paksarian et al found that mobility at all ages except the year of birth was significantly associated with development of narrowly defined schizophrenia. The likelihood of narrowly defined schizophrenia increased with increasing age and number of moves per year, with the highest risk observed among children who moved three or more times when they were aged 14 years (relative risk=3.72 vs those who did not move).

Similar results were observed for broadly defined schizophrenia, but there were fewer associations with bipolar disorder, and these showed less of an increase with age and number of moves.

The researchers note that their findings were not modified by gender, having siblings or distance moved but that there was modest evidence of an interaction with family history of psychiatric diagnosis.

The fact that distance moved did not alter the risk suggests that “both municipality and region changes are proxies for changes of school”, they remark.

Indeed, “[t]he potential importance of school change is consistent with the lower magnitude of associations of mobility in early childhood, before children enter school, and the higher magnitude of associations during adolescence, when peer relationships are especially salient.”

The authors add that it is currently unknown whether their findings reflect causal effects of mobility on the development of psychotic disorders or whether mobility is a marker for other childhood adversities such as parental discord.

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