Summary: A large longitudinal study of more than one million fathers in Sweden reveals an unexpected pattern in paternal mental health: diagnoses decline during partner pregnancy and the early months after birth, then rise markedly about one year after delivery. Clinical diagnoses of depression and stress-related disorders increased by roughly 30 percent at the end of the first postpartum year compared with the year before conception.
The delayed rise in diagnoses suggests that the cumulative demands of parenthood — including disrupted sleep, financial strain, shifting relationships, and prolonged caregiving stress — may overwhelm many fathers after the initial adjustment period. The findings point to a gap in postnatal support systems that typically concentrate on maternal care during the immediate weeks following delivery, while fathers may face growing vulnerability later.
Key Facts
- About a 30% increase: One year after childbirth, clinical diagnoses for depression and stress-related disorders among fathers were more than 30% higher than rates recorded before pregnancy.
- Initial decrease in diagnoses: The risk of receiving a psychiatric diagnosis fell during the partner’s pregnancy and in the early postpartum months compared with the preconception period.
- Return to baseline for some disorders: Rates for anxiety and substance-related disorders (alcohol and nonalcohol drug use) returned to pre-pregnancy levels by the one-year mark rather than remaining elevated.
- Likely underestimation: Because the study measured clinically recorded diagnoses, the true extent of paternal mental health struggles is likely higher, as many men do not seek formal care.
Source: Karolinska Institutet
Fathers in Sweden were less likely to receive a psychiatric diagnosis during partner pregnancy and the months immediately following birth, but diagnoses of depression and stress-related disorders rose significantly about one year later.
These findings come from a new study published in JAMA Network Open by researchers from Karolinska Institutet and Sichuan University. By linking nationwide registers, the team tracked newly diagnosed psychiatric disorders among fathers from one year before conception until one year after delivery. The cohort included more than one million fathers and nearly two million births between 2003 and 2021.
“The transition to fatherhood brings many rewarding experiences but also new and persistent stresses,” says Jing Zhou, PhD student at the Institute of Environmental Medicine, Karolinska Institutet, and co-first author. “Intimate moments with a newborn are meaningful, yet changes in the couple’s relationship and reduced sleep quality can raise the risk of mental ill-health.”
The researchers found that overall incidence rates of clinically diagnosed psychiatric disorders were lower during pregnancy and in the early postpartum period than during the year before conception. For anxiety and substance-related disorders, rates dipped and later returned to similar pre-pregnancy levels. In contrast, depression and stress-related disorders exhibited a delayed upward trend, increasing by more than 30% in the late postpartum period.
“The delayed rise in depression was surprising and highlights the importance of monitoring fathers’ mental health well beyond the first few months after birth,” says Donghao Lu, senior lecturer and associate professor at the Institute of Environmental Medicine and the study’s corresponding author. The authors emphasize that clinical diagnoses are only one measure; many fathers may experience symptoms without seeking care, meaning the study likely underestimates overall need.
Implications for care and policy
By pinpointing when the risk of deterioration increases, the study suggests that health services and family support programs could better schedule screening and outreach. Current perinatal care often prioritizes mothers in the immediate postpartum weeks; adding structured follow-up for fathers around the late postpartum period could help detect and treat depression and stress-related disorders earlier, benefiting the whole family.
The study was a collaboration between Karolinska Institutet, Sichuan University, and Uppsala University. Funding came from Karolinska Institutet’s strategic research area in epidemiology and biostatistics, the Swedish Research Council, and the European Research Council. The authors reported no conflicts of interest.
Key Questions Answered:
A: The pattern is consistent with a cumulative stress effect. Early months focus on immediate newborn care, but ongoing sleep disruption, financial pressures, and evolving relationship roles can build up and peak around the end of the first year.
A: Not necessarily. The dip in recorded diagnoses may reflect delayed help-seeking, prioritizing the partner’s needs, or temporary protective factors. Symptoms can go undetected until stress accumulates.
A: Timing and drivers differ. Maternal depression often relates to biological and hormonal changes soon after birth, while paternal depression appears more tied to lifestyle and social stressors that accumulate over time.
Editorial Notes:
- Edited by a Neuroscience News editor.
- Full journal paper reviewed for this summary.
- Additional context provided by editorial staff.
About this research
Author: Press Office, Karolinska Institutet
Source: Karolinska Institutet
Contact: Press Office – Karolinska Institutet
Image: Image credited to Neuroscience News
Original Research: “Psychiatric disorders among fathers in Sweden before, during and after partner pregnancy” by Nanyan Xiang, Jing Zhou, Yifei Lin, Yihui Yang, Miriam Martini, Bowen Tang, Yufeng Chen, Fotios C. Papadopoulos, Emma Fransson, Alkistis Skalkidou, Jin Huang, and Donghao Lu. Published in JAMA Network Open. DOI: 10.1001/jamanetworkopen.2026.2725
Abstract
Psychiatric disorders among fathers in Sweden before, during and after partner pregnancy
Importance
Paternal psychiatric disorders during the perinatal period can affect the entire family’s well-being, yet these conditions are often underrecognized and their timing and incidence remain poorly described.
Objective
To examine incidence patterns of newly diagnosed psychiatric disorders among fathers in Sweden in the year before conception, during partner pregnancy, and in the first year after childbirth.
Design, Setting, and Participants
This prospective cohort study linked national register data on all fathers of children born in Sweden between January 1, 2003, and December 31, 2021, following each father from one year before conception through one year postpartum. Data analysis occurred from October 1, 2024, to March 31, 2025.
Exposures
The study compared the reference period of one year before pregnancy with the period during pregnancy and the first postpartum year.
Main Outcomes and Measures
Weekly and annual incidence rates of clinical diagnoses for any psychiatric disorder and nine specific disorder categories were calculated, standardized by age and calendar year. Adjusted Poisson regression estimated incidence rate ratios comparing pregnancy and postpartum periods to the preconception baseline.
Results
The study included 1,915,722 births from 1,096,198 fathers (mean age at childbirth 33.8 years). Incidence rates for any diagnosed psychiatric disorder were lower during pregnancy and early postpartum weeks than in corresponding preconception weeks, then returned to comparable rates later postpartum. Anxiety and substance-related disorders showed similar patterns. By contrast, incidence rate ratios for depression and stress-related disorders rose by about 30% toward the end of the first postpartum year. Tobacco use disorder, ADHD, bipolar disorder, and psychosis showed relatively stable rates across periods.
Conclusions and Relevance
Fathers in Sweden were less likely to receive psychiatric diagnoses during a partner’s pregnancy and early postpartum period but experienced a delayed increase in diagnoses of depression and stress-related disorders toward the end of the first year after childbirth. These patterns may reflect temporary protection or delayed care-seeking during the transition to fatherhood and underline the need for targeted mental health surveillance and support for fathers in the late postpartum period.