The results of this study support the perspective that the associations between parenthood and mental health are complex and highly dependent on contextual factors. It is theoretically interesting and in contrast to many previous US studies [12, 29] that the initial simple analysis indicated a lower prevalence of both anxiety and depressive symptoms among parents compared to non-parents. However, the differences are too small to have any public health significance. Moreover, further analysis showed that these parent/non-parent differences were in part confounding effects of relationship variables, and were also inconsistent across specific subgroups.
The majority groups of married parents and cohabiting parents without a prior divorce share the absolute base level of anxiety and depression prevalence with non-parents in the same subgroups. In contrast, the small subgroup of single parents showed only a moderate elevation in prevalence of anxiety if never married, but doubled anxiety prevalence if a divorce was part of their relationship history. However, these elevations were not significantly different from equivalent non-parents subgroups, suggesting that being a parent does not represent the risk associated with these subgroups. Depressive prevalence showed a somewhat similar picture with almost twice as high as prevalence among all single persons regardless of parenthood, also pointing towards other factors than parenthood in itself. Finally, the effects of social class and education were small in a population perspective, and did not influence the conclusions regarding parenthood or other family status characteristics. We will now address methodological issues, before we discuss interpretations.
The broad epidemiological perspective of this study may conceal effects on mental health of specific parenting events (e.g. becoming a parent, births of additional children) as well as on the challenges associated with certain stages of parenting (e.g. caring for infants or adolescents). Based on the overall results, however, these events or stages do not seem to result in longer term effects on mental health, or else parents overall would report a reduced mental health. There may be transient effects, or these effects are relevant only to limited groups. Alternatively, such specific negative influences are outweighed by positive parenthood factors across time.
An advantage of the database utilized for the present study is that the recruitment methodology reduced the influence of sampling bias because the entire population of a geographical area was personally invited. The present study included parents with decades of caregiving experience as well as new parents and non-parents, differentiated gender and single as well as married and cohabiting persons, and allowed some differentiation based on prior marital history. At the same time, this database has limitations, in particular by not identifying non-custodial biological parents or adoptive or foster parents, or specifying prior marital history for those currently married. Neither can it identify “empty-nested” parents, which required the exclusion of age groups above 50, where the rate of “empty-nested” parents rises steeply. Because Norway is highly homogeneous, especially in the targeted geographic region, this study was also insensitive to factors associated with ethnicity or migration, which can be powerful contextual factors for parenthood in some populations.
The large statistical power in this study implies that statistical significance could be attained for minor effects when analysing the entire sample. On the other hand, important effects can become rejected as statistically non-significance because they are represented by small subgroups. This may be a particular problem for the small group of widowed persons in the present study. Using cut-off categorizations of anxiety and depression could have reduced the statistical sensitivity to differences in smaller subgroups, but analyses of continuous variables did not confirm this.
Coding parenthood based on combining family composition and age implies a danger of misclassifications into both parents and non-parents. The exclusion of persons below 30 and above 50 years of age and 362 individuals with ambiguous information reduced but did not rule out this weakness. If the survey database had included direct questions on parenthood, this limitation would have been removed.
Interpretations focused on relationship history and consequences
The traditional interpretation when finding a reduced mental health among single parents has been focused on the strains and disadvantages of combining parenthood with having to handle responsibilities and problems alone [3, 9]. However, single parents are not necessarily negatively burdened by increased workload and responsibility. A recent study on economically poor single mothers showed a positive mental health effect of full-time employment despite small economic gains . In a study of single mothers specifically, mental health problems was limited to divorced single mothers and not observed in the never married single mothers , but the study lacked a non-parent comparison. Indeed, divorce and particularly multiple relationship transitions have been associated with increased anxiety and depression in several previous studies, which has usually been interpreted as resulting from emotional, social and practical strains . Thus, relationship history may be part of the explanation why single parenthood is associated with reduced mental health.
In addition to prior and present strains, a selection process may also be part of the explanation. However, several studies fail to find a selection effect of anxiety or depression related to marriage [26, 34, 44]. In contrast, studies have shown that both depression and anxiety predict divorce and marital instability over the lifetime [40, 41], and that depression is retained across divorce and remarriage , at least partly . This is consistent with findings that anxiety as well as depression is often stable or recurrent over time [8, 39], thus possibly contributing to difficulties in maintaining relationships. Hence, the observed elevated anxiety and depression may reflect one of the causes of divorce and therefore single status, and not only reflecting prior and present strains. Our study was not designed to disentangle relationship history in detail. It will be important in future studies on the mental health of different groups of parents to collect such information.
Interpretation focused on social–political context
The result of the present study diverges in part with previous research [7, 9, 17] in not finding an elevated depressive prevalence among single parents (there was only an elevated anxiety prevalence), no mental health difference between married and cohabiting couples (unless divorced), and no differential patterns between mother and father. One interpretative approach to these differences with these previous studies conducted in the US is the social and political difference regarding families and parenthood between the US and Norway. More specifically, there are legal and economic differences as well as differences in attitudes, values, and practices regarding parenthood, single parenthood, divorce, cohabitation, and gender equality between the two countries. Generally, providing advantages for parenting in Norway, these differences may lessen some of the negative effects of parenthood or a disadvantaged situation for some groups in American society. The Norwegian socio-political and cultural context implies that cohabiting parents and single parents as groups are less selected and less stigmatized than in the USA, and live in a society that supports parenthood in legal, economic and practical ways regardless of marital status. From Denmark, where attitudes and social policy are similar, a large twin-study reported substantial positive effect from having a first-born child on well-being and happiness, especially within a relationship, but not when having additional children .
In the USA, cohabitation and single parenthood may function as markers for other factors representing the primary mental health risks. For example, US research has led to expectations that cohabiting new mothers are “worse off” than married mothers, because cohabitation is associated with less well-being, poorer health, higher incidence of alcohol abuse and domestic violence, and lower socio-economic status compared to being married , although this has not been a uniform conclusion . However, in Norway, cohabiting persons are almost indistinguishable from those who are married in public statistics on health, psychological, and socio-economic factors . This has been attributed to that cohabitation is a widely accepted, essentially normative living arrangement. Cohabitation is also partly equalized to marriage in selected legal and regulatory reforms, such as regarding insurance coverage and tax benefits . Consequently, cohabitants cannot be expected to be as disadvantaged in Norway as in the US.
Single parents may also be less burdened in Norway than in the US. The Norwegian tax and welfare benefits specifically for single parents, combined with general high minimum wages and low unemployment, constitute a favourable economic context for child-rearing parents, whether in a partnership or single status [5, 34]. Moreover, parenthood is encouraged by generous state benefits for parents and high-quality out-of-home day-care is readily available. Such services may buffer some of the traditional burdens of parenthood, especially for single parents. Active fatherhood is also explicitly valued in public debate and political reforms, such as by including fathers in generous parental leave following birth of a child . These contextual factors can go some way towards equalizing the ongoing burdens of parenthood.
Thus, the results of this study may point to that the contextual factors that societies offer families do make a difference, enabling a more positive parental experience and better mental health for parents of different types. Also, differences in family-related norms result in group compositions that change the value of group factors in large-scale studies in different societies. Cross-cultural longitudinal research contrasting such factors and following individual family history are necessary to understand the complex interplay with mental health for the large majority of people who become parents.