Moving as a child is associated with an increased risk of depression in adulthood

A recent study published in JAMA Psychiatry examines whether moving during childhood and different income levels in neighborhoods are associated with the risk of depression in adulthood.

The global economic burden of mental illness is projected to increase to US$6 trillion by 2030, exceeding the combined costs of diabetes, cancer and chronic respiratory diseases. The causes of mental illness are multifactorial and may include socioeconomic, biological and psychological factors.

Income and neighborhood characteristics can positively or negatively influence a person’s health. For example, positive social interactions can give people a sense of control over their environment, reducing their risk of depression.

Depression in adulthood and childhood deprivation are positively associated. Children who frequently move often are often at greater risk of mental health problems in the future, which may be due to disruptions in social networks, family routines, and emotional relationships. Thus, frequent moves in childhood may be a potential risk factor for mental health problems in the future.

The present study used national Danish registers to test the hypothesis that more frequent moves during childhood and higher income levels in the neighbourhoods of residence are associated with a greater risk of depression in adulthood.

The study cohort included all Danish citizens born between 1 January 1982 and 31 December 2003 and living in Denmark for the first 15 years of life. These individuals were followed until diagnosis of depression, emigration, death, or until 31 December 2018.

Impact measures included the average income poverty index for the entire childhood and the area income poverty index for the same period. Individuals were classified as "remainers" or "movers" depending on whether they remained in the same data area throughout childhood.

The study cohort included 1,096,916 individuals, of whom 51.4% were men. During the follow-up period, 35,098 individuals were diagnosed with a depressive episode, of whom 32.4% were men and 67.6% were women.

A significant association was found between higher incidence of depression in adulthood and educational attainment, employment status, and lower parental income after controlling for individual-level risk factors. An increased risk of depression in adulthood was also found to be associated with younger maternal age and, to a lesser extent, paternal age.

Moving during childhood was significantly associated with higher rates of depression in adulthood compared with those who did not move. If a child moved more than once between the ages of 10 and 15, the risk of depression in adulthood was 1.61 times higher. The effect of moving on depression in adulthood remained regardless of whether the child lived in a more or less deprived area during childhood.

A small but consistent association was found between the risk of depression and neighborhood income poverty at all ages. The risk was slightly reduced after individual-level adjustment.

Overall, for every 2% increase in the prevalence of depression, there was a one standard error increase in income poverty during the first 15 years of life. Results were similar when excluding schizophrenia spectrum disorders or substance use disorders.

When the poverty index was divided into quintiles, interesting heterogeneities were observed. For example, if a person was born in an area with the least income poverty and lived in an area with moderate income poverty at age 15, the risk of depression increased by 18%. In contrast, the opposite pattern, with a lower risk of depression, was observed for those born in poorer areas but moving to slightly higher income areas by age 15.

The results of the study confirm the protective role of a stable home environment in childhood against depression in adulthood. Therefore, policies aimed at creating and supporting a stable childhood should be developed and supported.

A key limitation of the sample used in this study is the biased representation of patients with more severe forms of depression. However, the researchers hypothesize weaker associations in cases of milder forms of depression. In addition, imperfect measurements of covariates or imperfect description of areas may lead to some degree of undetected residual confounding.

An additional limitation is the inability of Danish registers to capture the complexity of blended families. For example, in a family breakdown, a child may have separate mother and father homes between which the child moves frequently, but the register will only list one address for each child.