Children of low-income families have greater risk of developing mental disorders later in life

The results gained in a study involving approximately one million Danish children increase the understanding of how socio-economic differences in childhood affect the development of mental disorders in the Nordic countries.

Researchers at the University of Helsinki, Aarhus University and the University of Manchester have investigated the link between the socio-economic position of parents and the risk of children developing mental disorders later in life.

As research data, the project employed a cohort of roughly one million Danish children born between 1980 and 2000. The income of their parents was measured in the year of birth as well as when the children were 5, 10 and 15. Five income brackets were utilized in each measurement point, enabling the researchers also to measure income fluctuation during childhood.

The mental health of the children included in the dataset was monitored from the age of 15 until mental disorder diagnosis or the end of 2016, and thus the longest follow-up was until the age of 37. Data on mental disorder diagnoses were obtained from the Danish psychiatric register. In other words, the study subjects identified this way had ended up in treatment at a psychiatric hospital or outpatient clinic due to mental health problems. The overall follow-up period in the study was carried out from 1995 to 2016.

The results have been published in the BMC Medicine journal.

Our study demonstrated that the longer children grew up in families with low-income parents, the greater their risk was of developing a mental disorder."

Christian Hakulinen, lecturer in health psychology, University of Helsinki

One quarter of those born in the lowest parental income quintile developed a mental disorder

Based on the study findings, 25.2% of children born into the lowest parental income quintile developed a clinically diagnosed mental disorder by the time they turned 37. Correspondingly, 13.5% of children born in the top parental income quintile developed a mental disorder in the same period of time.

"From among the mental disorders studied, the only exception was eating disorders. In their case, low parental income was associated with a lower risk of developing an eating disorder," Hakulinen says.

The results show that the longer children lived in low-income families, the greater their risk was of developing a mental health disorder.

"We observed that a third of the children who lived in low-income families throughout their childhood were later diagnosed with a mental disorder. At the same time, 12% of the children who grew up in the top income quintile were later diagnosed with a mental disorder," Hakulinen says.

More measures in childhood to prevent mental disorders?

Although the study focused on Danish families, Hakulinen believes the findings can be used to draw conclusions also in the context of other Nordic countries, since our healthcare systems are fairly similar in the treatment of mental disorders.

"Mental disorders that reduce functional capacity are typically treated in secondary care in both Denmark and the rest of the Nordic countries, particularly if they appear in early adulthood," says Hakulinen.

The results indicate that the socioeconomic conditions in childhood are associated with the onset of mental disorders. In fact, Hakulinen would like attention to be paid to the prevention and treatment of such disorders already in childhood.

"Measures focused on childhood, such as interventions in support of parenthood, could benefit low-income families in particular. This would make it possible to tackle psycho-social risk factors, which financial challenges typically aggravate," Hakulinen notes.