Summary: A massive longitudinal study reveals a surprising trend in paternal mental health: while psychiatric diagnoses for fathers decrease during pregnancy and early infancy, they spike a year after birth significantly. Analyzing data from over one million fathers in Sweden between 2003 and 2021, researchers found that diagnoses for depression and stress-related disorders increased by over 30 percent compared to pre-pregnancy levels.
This delayed onset suggests that the cumulative pressures of parenthood—including sleep deprivation and relationship shifts—may overwhelm fathers long after the initial “honeymoon phase” of a new arrival. The findings highlight a critical gap in postnatal support, which traditionally focuses almost exclusively on mothers during the immediate weeks following delivery.
Key Facts
- The 30% Spike: One year after a child’s birth, fathers saw a 30 percent increase in clinical diagnoses for depression and stress-related disorders compared to their baseline health before the pregnancy.
- Initial “Protective” Phase: Paradoxically, the risk of receiving a psychiatric diagnosis actually decreased during the partner’s pregnancy and the first few months of the child’s life.
- Return to Baseline: Rates for anxiety and substance-related disorders (alcohol and drugs) eventually returned to pre-pregnancy levels by the one-year mark, rather than staying elevated.
- Hidden Struggle: Because the study relied on clinical diagnoses, researchers suggest the actual number of struggling fathers is likely much higher, as many men do not seek formal medical care for mental health.
Source: Karolinska Institute
Fathers in Sweden are less likely to receive a psychiatric diagnosis during their partner’s pregnancy and in the months following the birth of their child.
However, diagnoses of depression and stress-related disorders increase a year later, according to a new study published in JAMA Network Open by researchers at Karolinska Institutet in Sweden and Sichuan University in China.
“The transition to fatherhood often involves both positive experiences and a range of new stresses,” says Jing Zhou, PhD student at the Institute of Environmental Medicine, Karolinska Institutet, and co-first author of the paper.
“Many cherish the intimate moments with their child, whilst at the same time the relationship with their partner may be affected and sleep quality may deteriorate, which can contribute to an increased risk of mental ill-health.”
The study covers over a million fathers whose children were born in Sweden between 2003 and 2021. By linking various national registers, the researchers have been able to track how often men received a new psychiatric diagnosis from one year before their partner’s pregnancy until their child turned one.
30 percent increase one year later
The results show that the risk of receiving a psychiatric diagnosis decreased during pregnancy and the first few months after birth, compared with the year before. One year after the child’s birth, the rate of anxiety and alcohol- and drug-related diagnoses had returned to levels similar to those before pregnancy.
However, for depression and stress-related disorders, a negative trend was observed. These diagnoses increased by over 30 percent one year after childbirth compared to before pregnancy.
“The delayed increase in depression was unexpected and underscores the need to pay attention to warning signs of mental ill-health in fathers long after the birth of their child,” says Donghao Lu, senior lecturer and associate professor at the Institute of Environmental Medicine, Karolinska Institutet, and the paper’s corresponding author.
Provide support at the right time
The researchers emphasise that the study is based on clinical diagnoses, which means that men who did not seek medical care may have been overlooked. Despite this, the results provide a clear picture of when, during parenthood, the risk of mental ill-health may be greatest.
“By identifying periods of increased vulnerability, healthcare providers and other stakeholders can more easily offer support,” says Jing Zhou. “Postnatal depression is often discussed for new mothers, but fathers’ well-being is also important, both for themselves and for the whole family.”
The study was conducted in collaboration with researchers at Sichuan University in China and Uppsala University in Sweden.
Funding: It was funded by Karolinska Institutet’s strategic research area in epidemiology and biostatistics, the Swedish Research Council and the European Research Council. The researchers report no conflicts of interest.
Key Questions Answered:
A: It’s likely a “cumulative stress” effect. While the first few months are focused on the newborn, the long-term reality of sleep loss, financial pressure, and changing relationship dynamics takes a toll that often peaks around the one-year mark.
A: Not necessarily. The study found fewer diagnoses during pregnancy, which might mean fathers are prioritizing their partner’s health or simply suppressing their own symptoms until the initial crisis of a new baby has passed.
A: The timing certainly is. While maternal depression often peaks shortly after birth due to hormonal shifts, paternal depression appears more linked to lifestyle stressors that build up over the first year of the child’s life.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neurology and aging research news
Author: Press Office
Source: Karolinska Institutet
Contact: Press Office – Karolinska Institutet
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“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. 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 health of the entire family; however, these conditions have often been underrecognized, and little is known about their incidence and timing of onset.
Objective
To investigate incidence patterns of new-onset diagnosed psychiatric disorders among men in Sweden before, during, and after a partner’s pregnancy.
Design, Setting, and Participants
This prospective cohort study used linked national register data for all fathers of children born in Sweden between January 1, 2003, and December 31, 2021, with follow-up from 1 year before to 1 year after pregnancy. Data were analyzed from October 1, 2024, to March 31, 2025.
Exposures
The time during pregnancy and 1 year after childbirth (post partum) were considered the risk periods, while 1 year before pregnancy (before conception) was used as the reference period.
Main Outcomes and Measures
Annual and weekly incidence rates (IRs) of clinical diagnoses of any psychiatric disorder and 9 type-specific disorders were calculated and standardized by age and calendar year. Adjusted Poisson regression analysis was used to further estimate incidence rate ratios (IRRs) of psychiatric disorders during and after pregnancy compared with before conception.
Results
This study included 1 915 722 births from 1 096 198 fathers (mean [SD] age at childbirth, 33.8 [6.2] years) in Sweden. IRs of any diagnosed psychiatric disorder were lower during pregnancy (eg, pregnancy week 1: IR, 5.50 [95% CI, 4.69-6.31] per 1000 person-years) and the early postpartum period (eg, postpartum week 1: IR, 5.19 [95% CI, 4.41-5.97] per 1000 person-years) than in the corresponding preconception weeks (eg, preconception week 1: IR, 7.00 [95% CI, 5.97-8.04] per 1000 person-years); they returned to comparable rates later post partum. This pattern was also observed for IRRs of anxiety, alcohol use, and drug use (ie, the use of nonalcohol, nontobacco psychoactive drugs) disorders.
IRRs of depression (eg, postpartum weeks 45-49: IRR, 1.30 [95% CI, 1.12-1.52]) and stress-related disorders (eg, postpartum weeks 45-49: IRR, 1.36 [95% CI, 1.15-1.61]), however, showed a notable 30% increase toward the end of the first postpartum year. In contrast, IRRs of diagnosis of tobacco use disorder, attention-deficit/hyperactivity disorder, bipolar disorder, or psychosis remained relatively stable before, during, and after pregnancy.
Conclusions and Relevance
In this nationwide cohort study, fathers in Sweden were less likely to be diagnosed with a psychiatric disorder during a partner’s pregnancy and early post partum than before conception, but IRs returned to comparable levels thereafter. These incidence patterns may reflect transient protection and delayed detection during the transition to fatherhood and support the need for paternal mental health surveillance, particularly for increased depression and stress-related disorders in the late postpartum period.
