The effects of parenthood on mental health are complex, but a new study published in Health Sociology Review reveals a different angle to the relationship: how a person's mental health at 16 influences whether or not he or she becomes a parent, as well as whether or not parenthood has an effect on that mental health going forward.

To explore the 'selection effect' first, Sara Kalucza and her colleagues from Umea University in Sweden studied data from the 1000 individuals included in the 'Northern Swedish Cohort' dataset. They examined in detail the information taken at the ages of 16, 18, 21, 30 and 43 as well as various aspects of their subjects' lives and self-reported mental health.

What they discovered was that men who reported health problems at the age of 16 had a lower probability of becoming fathers than men who did not report the same issues; this 'selection effect' remained the same even when 'family variables' like parental social class or siblings were taken into account. For women, the picture was different: their self-reported mental health at 16 did not affect their entry into parenthood, although other factors, like having many siblings themselves, did.

As part of their study, Kalucza and her colleagues also wanted to know what effect parenthood had on the mental health of parents when their mental health before becoming parents was taken into account. As with the first question they explored, the effects were not the same for men and women. On average, they found, men had better mental health than women. But in terms of the relationship between mental health and parenting, they conclude that women benefit from becoming parents, but men, "for whom there is a selection of healthy men into parenthood, do not necessarily become healthier from becoming a parent".

The authors were particularly intrigued by what they call the "lack of negative relationships between parenthood and subsequent mental health in a Scandinavian context". They suggest their observation could indicate that being a parent in a country with a strong welfare system, paid parental leave and high-quality childcare has different implications for parental mental health compared to the situation in a country like the United States. An exploration of that particular angle, as well as more general explorations of the relationship between mental health and parenting, are needed to draw further conclusions.