Latest findings from PsychGen
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Presented as short summaries of our latest publications
Understanding the Long-Term Psychological Effects of COVID-19 Quarantine
A new study published in BMC Medicine by researchers from Norway and Iceland has investigated the long-term psychological effects of COVID-19 quarantine on mental health. The research, led by Li Lu from the University of Oslo and PsychGen, analyzed data from 105,344 participants across three longitudinal cohorts in Norway and Iceland.
The study found that individuals who had been quarantined during the pandemic showed higher prevalence rates of depression and anxiety, with these conditions defined as scoring 10 or more on the PHQ-9 and GAD-7 screening tools respectively. Notably, the duration of quarantine was associated with increased mental health symptoms in a dose-response manner. Those quarantined for more than 4 weeks had a 72% higher prevalence of depression and a 76% higher prevalence of anxiety compared to those who had not been quarantined.
The longitudinal analysis, with an average follow-up period of 20.5 months, confirmed that these effects persisted over time. Interestingly, the association between quarantine and depression was stronger among females, individuals aged 35-64 years, and those without a COVID-19 infection.
This research aligns with the PsychGen center's aim to understand how environmental factors, such as quarantine experiences, influence mental health outcomes. By examining how these stressors affect different population groups, the study provides valuable insights for developing targeted interventions to support mental well-being during future public health crises.
Strengths: The study's large sample size across multiple cohorts, longitudinal design, and use of validated assessment tools for measuring mental health symptoms provide robust evidence for the findings.
Limitations: The study relied on self-reported data, which may be subject to recall bias. Additionally, the cohorts had different demographic compositions, and the generalizability to other populations may be limited.
Publication: Lu, L., Wang, Y., Ebrahimi, O.V. et al. Long-term psychological effects of COVID-19-related quarantine: an observational study of three cohorts in Norway and Iceland. BMC Med 23, 519 (2025). https://doi.org/10.1186/s12916-025-04349-8
New Research Identifies Distinct Types of Postpartum Depression
Researchers have identified nine different subtypes of postpartum depression (PPD) in a large Norwegian study involving 7,859 women. The study was led by Anna E. Bauer at the University of North Carolina in collaboration with researchers from the PsychGen Center. They used advanced statistical methods to analyze symptom patterns, trauma history, pain during pregnancy, and genetic factors.
The findings reveal that women with PPD can be grouped into different categories based on symptom severity, timing of onset, trauma history, and physical health factors. For example, one subtype (28% of participants) showed severe depression symptoms combined with trauma history and had elevated genetic risk for several psychiatric conditions. Another group (10%) had mild symptoms with a protective genetic profile.
This research aligns with the work of the PsychGen center, which aims to understand how genes and environmental factors influence mental health conditions throughout lifespan. The findings demonstrate the importance of personalized approaches to prevention and treatment of postpartum depression.
The study has strengths including large sample size and validation in independent groups. Limitations include reliance on self-reported data and the relatively homogeneous Norwegian population, which may limit generalizability to more diverse groups.
Read the full publication: Bauer, A.E., Jaholkowski, P., Lu, Y. et al. Identification and validation of postpartum depression subtypes: a population-based cohort study. eClinicalMedicine 89, 2025. https://doi.org/10.1016/j.eclinm.2025.103540