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• Sanchez, Alejandra Martinez; Pettersen, Johanne Hagen; Ask, Helga; Havdahl, Alexandra & Hannigan, Laurie John (2026). regkit: facilitating manipulation, analysis and visualization of data from Norwegian health and population registers. Journal of Open Source Software (JOSS). 11(125), s. 10240–10240. doi: 10.21105/joss.10240. Fulltekst i vitenarkiv
• Skelton, Megan; Mitchell, Brittany L.; Assary, Elham; Li, Danyang; Morneau-Vaillancourt, Genevieve & Murphy, Alan E. [Vis alle 47 forfattere av denne artikkelen] (2026). Genome-wide meta-analysis of quantitatively measured generalized anxiety symptoms in individuals of European ancestry. Nature Human Behaviour. s. 1594–1608. doi: 10.1038/s41562-026-02476-7. Fulltekst i vitenarkiv Vis sammendrag

  Anxiety is heritable and exists on a continuum, with symptoms ranging from adaptive threat response to clinical disorder. Here we performed a genome-wide association meta-analysis of generalized anxiety symptom severity in 693,869 individuals of European ancestry from 14 cohorts. We identified 80 independent genome-wide significant variants within 74 loci, 39 of which were newly associated with anxiety. SNP-based heritability was 5.9% (posterior s.d. = 0.15%). Polygenic scores were significantly associated with anxiety symptom severity and disorder in European, African and South Asian ancestry samples (R2 = 1.2–2.9%). Significant genetic correlations (rg) were estimated with mental and physical health traits, including case–control anxiety, neuroticism and depression (rg = 0.71–0.85), irritable bowel syndrome (rg = 0.57), coronary artery disease, endometriosis and migraine (rg = 0.20–0.27). Gene-based and pathway analyses implicated synaptic and axonal processes, with enriched expression in the brain. These findings highlight the discovery power gained from analysing a quantitative trait rather than a case–control phenotype in anxiety genetics.

• Quinn, Liam; Caspersen, Ida Henriette; Magnúsdóttir, Ingibjörg; Wang, Yue; Lundberg, Mischa & Gådin, Jesper [Vis alle 38 forfattere av denne artikkelen] (2026). The role of genetic liability for psychiatric disorders and personality traits in post covid syndrome: data from three Nordic population cohorts. EClinicalMedicine. 95. doi: 10.1016/j.eclinm.2026.103928. Fulltekst i vitenarkiv
• Bjørndal, Ludvig Daae; Hegemann, Laura Elizabeth; Pettersen, Johanne Hagen; Corfield, Elizabeth Claire; Hannigan, Laurie & Yilmaz, Zeynep [Vis alle 14 forfattere av denne artikkelen] (2026). Investigating Relationships Between Genetic Risk, Childhood Maltreatment, and Eating Disorders in Women. Biological Psychiatry: Global Open Science. 6(5). doi: 10.1016/j.bpsgos.2026.100761. Fulltekst i vitenarkiv Vis sammendrag

  Background Genetic and environmental factors contribute to eating disorder risk, yet their interplay is poorly understood. We examined whether childhood maltreatment and polygenic scores for anorexia nervosa (PGS-AN) and binge-eating broad (PGS-BEB) are associated with eating disorders. We also examined the interactions between childhood maltreatment and PGSs in predicting eating disorders. Methods This nested case-control study used data from up to 63,989 mothers in the MoBa (Norwegian Mother, Father and Child Cohort Study). Mothers reported on their own experiences of 4 childhood maltreatment types: long-term humiliation or degradation, threats to self or someone close, physical abuse, and sexual abuse. Diagnoses of AN, bulimia nervosa (BN), binge-eating disorder (BED), purging disorder (PD), and binge-eating spectrum disorders (BESP) were obtained using self-report data from 5 time points and population health registers. Results The prevalence of AN, BN, BED, PD, and BESP was 2.19%, 4.15%, 10.39%, 0.60%, and 12.96%, respectively. All childhood maltreatment types were strongly associated with elevated eating disorder likelihood (with odds ratios [ORs] ranging from 1.71 to 3.29) as were eating disorder PGSs (with ORs ranging from 1.05 to 1.31). There were no multiplicative interaction effects between childhood maltreatment and PGSs. Small additive interactions were observed between PGS-AN and PGS-BEB and degradation/humiliation for BN and BESP in exploratory analyses. Conclusions Eating disorder PGSs and childhood maltreatment are associated with higher odds of eating disorders. Furthermore, we found tentative evidence of small additive interaction effects between polygenic liability and childhood maltreatment, suggesting that their combined influence further elevates the risk of some eating disorders.

• Pettersen, Johanne Hagen; Eilertsen, Espen Moen; Hegemann, Laura Elizabeth; Hannigan, Laurie; Lund, Ingunn Olea & Johannessen, Pia Myklebust [Vis alle 12 forfattere av denne artikkelen] (2026). Intra-familial dynamics of mental distress during the Covid-19 lockdown. Translational Psychiatry. 16(1), s. 1–9. doi: 10.1038/s41398-026-03876-z. Fulltekst i vitenarkiv Vis sammendrag

  Lockdowns and social restrictions imposed in response to the Covid-19 pandemic intensified the proximity and reciprocal exposure among members of nuclear families. It is unclear how variation in mental distress during this period is attributed to potential influences of family members. This study used genetic data from adolescents (n = 4 388), mothers (n = 27 852) and fathers (n = 25 953), to disentangle the contributions of parent-driven, child-driven, and partner-driven components to mental distress during the first two months of the Covid-19 lockdown. Separate models also included adolescents’ non-pandemic mental distress as outcomes (n = 13 484). Trio genome-wide complex trait analyses separated two types of genetic components; direct–how an individual’s genotype is associated with their own mental distress, and indirect–how an individual’s genotype is associated with the mental distress of family members. A trio polygenic score (PGS) design was used to investigate associations of specific genetic liability factors with mental distress, and whether these changed over time (PGS×time). Results suggest that family-level genetic factors contribute to mental distress; variance components capturing indirect genetic effects accounted for 10% of adolescent mental distress (mother-driven), 2–3% of maternal (partner-driven), and 5% of paternal mental distress (child-driven). Mothers’ depression and ADHD PGS were positively associated with fathers’ mental distress. No PGS×time interactions were found. Direct genetic effects accounted for 9–10% variance in mental distress across family members, partly explained by genetic variants associated with anxiety, depression, ADHD and neuroticism. These findings highlight the importance of family dynamics and emphasize the potential value of including family members in mental health interventions.

• Slapø, Nora Berz; Jørgensen, Kjetil Nordbø; Nerland, Stener; Mørch-Johnsen, Lynn Egeland; Pettersen, Johanne Hagen & Roelfs, Daniel [Vis alle 23 forfattere av denne artikkelen] (2026). Relationship between N100 amplitude and T1w/T2w-ratio in the auditory cortex in schizophrenia spectrum disorders. Schizophrenia. doi: 10.1038/s41537-025-00715-w. Fulltekst i vitenarkiv Vis sammendrag

  Schizophrenia spectrum disorders (SCZspect) are associated with altered function in the auditory cortex (AC), indicated by lower N100 amplitude of the auditory evoked potential (AEP). Although the neural substrate behind lower N100 amplitude remains elusive, myelination in the AC may play a role. This study compared N100 amplitude and magnetic resonance imaging (MRI) T1 weighted and T2 weighted ratio (T1w/T2w-ratio), as a proxy of myelination, in the primary AC (AC1) and secondary AC (AC2) between SCZspect (n = 33, 48% women) and healthy controls (HC, n = 144, 49% women). We also examined the associations between N100 amplitude and T1w/T2w-ratios across groups. We finally explored N100 amplitude and T1w/T2w-ratios and the N100-T1w/T2w-ratio associations between male and female SCZspect and HC. N100 amplitude was significantly lower in male SCZspect compared to male HC (p = 0.01) and nominally lower in SCZspect compared to HC (p = 0.03). However, T1w/T2w-ratios in AC1/AC2 did not differ between groups, and no association was found between N100 amplitude and T1w/T2w-ratio in either group. These findings suggest that sex-specific effects should be considered in SCZspect neurophysiology research. Our results do not support the hypothesis of an association between lower N100 amplitude and lower T1w/T2w-ratio in the AC1/AC2 in SCZspect. More precise assessments of intracortical myelin are needed to understand the relationship between N100 amplitude and cortical myelination in the AC in SCZspect and in healthy controls.

• Johannessen, Pia Myklebust; Madsen, Christian; Hart, Rannveig Kaldager; Lund, Ingunn Olea; Pettersen, Johanne Hagen & Gustavson, Kristin [Vis alle 10 forfattere av denne artikkelen] (2026). Protective factors for maternal mental health and life satisfaction during the COVID-19 pandemic: a longitudinal analysis. BMJ Open. 16(1), s. 1–11. doi: 10.1136/bmjopen-2025-110204. Fulltekst i vitenarkiv Vis sammendrag

  Objective Mothers’ mental health and life satisfaction may have been negatively affected due to challenges during the COVID-19 pandemic. Given the risk of future crises, knowledge of possible mitigating factors in this population is essential. This study aims to examine whether the pandemic affected the level of protective factors such as social support, physical activity and employment situation, and how these factors are associated with mental distress and life satisfaction. Design Longitudinal cohort study. Outcome measures Primary outcomes were mental distress (measured by the eight-item version of the Hopkins Symptom Checklist) and life satisfaction (measured by the Satisfaction With Life Scale). As the first step, we investigated changes in the levels of social support (defined by the number and frequency of social contact), physical activity (average hours of physical activity during a week), employment situation (actively working vs sick leave or unemployed), alcohol consumption (measured by the Alcohol Use Disorders Identification Test-Consumption) and relationship satisfaction (measured by the five-item version of the Relationship Satisfaction Scale). Methods We analysed data from two waves of the Norwegian Mother, Father and Child Cohort Study (n=~18 000 mothers); one pre-pandemic wave and one wave where half of the sample responded after the onset of the pandemic, with pandemic exposure being defined by questionnaire response timing rather than cohort recruitment. To assess changes in protective factors over time and pandemic exposure, we used difference-in-differences analyses and regression discontinuity design. Associations between protective factors with mental distress and life satisfaction, and possible moderation by pandemic exposure, were investigated using multiple regression models with interaction terms adjusted for potential confounders. Results Apart from physical activity, which declined less across time in the pandemic group (B=0.09, 99% CI 0.05 to 0.12), protective factors did not change during the pandemic. Social support, employment situation and relationship satisfaction were associated with mental distress and life satisfaction, whereas physical activity showed a unique relationship with mental distress. Most associations were similar across pandemic exposure groups, except employment situation which appeared to have a stronger protective effect in the pandemic group (β=−0.12, 99% CI −0.24 to −0.00). Conclusions Changes over time in self-reported levels of protective factors were generally consistent among mothers independent of the pandemic. These factors appear to play an equally important role for mental distress and life satisfaction both under ordinary circumstances and during public health crises. Our findings enhance the understanding of how potential protective factors among mothers are associated with mental distress and life satisfaction in the context of a global stressor. Future studies should investigate additional mitigating factors that may be particularly relevant during global crises and explore the causal relationship between protective factors, mental health and life satisfaction.

• Hegemann, Laura Elizabeth; Eilertsen, Espen Moen; Pettersen, Johanne Hagen; Corfield, Elizabeth Claire; Cheesman, Rosa Catherine Gillespie & Frach, Leonard [Vis alle 11 forfattere av denne artikkelen] (2025). Direct and indirect genetic effects on early neurodevelopmental traits. Journal of Child Psychology and Psychiatry. ISSN 0021-9630. 66(7), s. 1053–1064. doi: 10.1111/jcpp.14122. Fulltekst i vitenarkiv Vis sammendrag

  Background Neurodevelopmental conditions are highly heritable. Recent studies have shown that genomic heritability estimates can be confounded by genetic effects mediated via the environment (indirect genetic effects). However, the relative importance of direct versus indirect genetic effects on early variability in traits related to neurodevelopmental conditions is unknown. Methods The sample included up to 24,692 parent-offspring trios from the Norwegian MoBa cohort. We use Trio-GCTA to estimate latent direct and indirect genetic effects on mother-reported neurodevelopmental traits at age of 3 years (restricted and repetitive behaviors and interests, inattention, hyperactivity, language, social, and motor development). Further, we investigate to what extent direct and indirect effects are attributable to common genetic variants associated with autism, ADHD, developmental dyslexia, educational attainment, and cognitive ability using polygenic scores (PGS) in regression modeling. Results We find evidence for contributions of direct and indirect latent common genetic effects to inattention (direct: explaining 4.8% of variance, indirect: 6.7%) hyperactivity (direct: 1.3%, indirect: 9.6%), and restricted and repetitive behaviors (direct: 0.8%, indirect: 7.3%). Direct effects best explained variation in social and communication, language, and motor development (5.1%–5.7%). Direct genetic effects on inattention were captured by PGS for ADHD, educational attainment, and cognitive ability, whereas direct genetic effects on language development were captured by cognitive ability, educational attainment, and autism PGS. Indirect genetic effects on neurodevelopmental traits were primarily captured by educational attainment and/or cognitive ability PGS. Conclusions Results were consistent with differential contributions to neurodevelopmental traits in early childhood from direct and indirect genetic effects. Indirect effects were particularly important for hyperactivity and restricted and repetitive behaviors and interests and may be linked to genetic variation associated with cognition and educational attainment. Our findings illustrate the importance of within-family methods for disentangling genetic processes that influence early neurodevelopmental traits, even when identifiable associations are small.

• Bang, Nina; Pettersen, Johanne Hagen; Nesset, Merete Berg; Rasmussen, Kirsten; Dahl, Hilde & Tesli, Natalia [Vis alle 15 forfattere av denne artikkelen] (2024). The Startle Response and Prepulse Inhibition in Psychosis and Violence: A Combined Electromyography and Electroencephalography Study. Schizophrenia Bulletin Open. 6(1). doi: 10.1093/schizbullopen/sgae031. Fulltekst i vitenarkiv Vis sammendrag

  There is a pressing need for biomarkers of violent behavior risk in psychosis. Previous research indicates that electrophysiological measures of automatic defensive reactions may have potential. The purpose of this study was to investigate associations between violent behavior in individuals with and without psychosis and electromyography (EMG) and electroencephalography (EEG) responses to startling auditory stimuli. Electromyography and EEG were recorded during an auditory startle paradigm from healthy controls (HC, n = 211), individuals with psychosis and a history of violent behavior (violent-PSY, n = 18), individuals with psychosis without a history of violence (nonviolent-PSY, n = 32), and individuals with a history of violence without psychosis (violent non-PSY, n = 22). We estimated the auditory startle response (ASR) and prepulse inhibition (PPI) using EMG (ie, EMGASR and EMGPPI) and the auditory-evoked potential (ie, AEPASR and AEPPPI) of the EEG. There were no significant effects of group on the EMGASR (P = .10) or the 30-, 60-, and 120-ms prepulse + pulse EMGPPI amplitudes (P = .11, P = .19, and P = .50, respectively). The N1 amplitude of the AEPASR was reduced in the violent-PSY group (P < .001) and the nonviolent-PSY group (P = .015) compared with HC. The P2 amplitude of the AEPASR was reduced in violent-PSY relative to nonviolent-PSY (P = .003), violent non-PSY (P = .016), and HC (P < .001). Together, these results show that EEG-based neural responses to startling auditory stimuli are promising biomarkers of violence risk in psychosis.

• Pettersen, Johanne Hagen; Hannigan, Laurie John; Gustavson, Kristin; Lund, Ingunn Olea; Pearson, Rebecca M. & Jensen, Pia [Vis alle 9 forfattere av denne artikkelen] (2024). COVID-19 Pandemic Quarantines and Mental Health among Adolescents in Norway. JAMA Network Open. 7(7). doi: 10.1001/jamanetworkopen.2024.22189. Fulltekst i vitenarkiv Vis sammendrag

  Importance: Adolescence is a critical developmental phase when mental health disorders, such as anxiety and depression, often emerge. Stringent public health measures and quarantine mandates during the COVID-19 pandemic could threaten adolescent mental health. Objective: To investigate the associations of public health measures and quarantine experiences with mental distress among Norwegian adolescents and to explore if certain vulnerability factors moderate these associations. Design, Setting, and Participants: This longitudinal cohort study used repeated measures to capture variations in mental distress explained by the stringency of public health measures and quarantine experiences. Data from the Norwegian Mother, Father, and Child cohort study were linked to national health registries and a national stringency index from April 1, 2020, to February 17, 2021. Participant included 7787 Norwegian adolescents aged 16 to 18 years. Data were analyzed from October 2022 to October 2023. Exposures: Stringency index of public health measures and quarantine experiences including recent quarantine (within the last 2 weeks) and quarantine frequency (cumulative number of quarantine episodes). Main Outcome and Measures: Mental distress was measured using the Hopkins Symptom Checklist across 6 data collection waves. Results: In this study, 7787 participants were included in the analysis (4473 female [57%]; mean [SD] age, 17.0 [0.6] years). Stringent public health measures (β = 0.18; SE, 0.02; P < .001), recent quarantine (β = 0.11; SE, 0.02; P < .001), and frequent quarantine (β = 0.08; SE, 0.01; P < .001) were associated with higher levels of mental distress. The associations between public health measures and mental distress were not moderated by sex, age, prepandemic anxiety or depression, or genetic liability for mental health conditions. Frequency of quarantine appeared to be more strongly associated with mental distress among younger adolescents (β = −0.04; SE, 0.01; P = .008), those with parents with lower education (β = −0.04; SE, 0.01; P = .007), and those with lower genetic risk for depression (β = −0.03; SE, 0.01; P = .006). Conclusions and Relevance: In this study, younger adolescents, those with parents with lower education, or those with low genetic liability for depression appeared more vulnerable when being quarantined several times. These findings emphasize the need for targeted support strategies to better protect adolescent well-being during future crises. Adolescents who experienced increased mental distress during the COVID-19 pandemic may be at risk of continued mental health problems and in need of ongoing support.

• Pettersen, Johanne Hagen; Hegemann, Laura; Gustavson, Kristin; Lund, Ingunn Olea; Jensen, Pia & Bulik, Cynthia M. [Vis alle 11 forfattere av denne artikkelen] (2024). Eating Problems Among Adolescent Boys and Girls Before and During the Covid-19 Pandemic. International Journal of Eating Disorders. ISSN 0276-3478. 58(1), s. 193–205. doi: 10.1002/eat.24314. Fulltekst i vitenarkiv Vis sammendrag

  Objective Studies suggest that adolescents reported more eating problems during the pandemic. Using a population-based sample, we compared eating problems—and how they associate with a range of personal characteristics and genetic factors—among adolescents before (June 2017–April 2020) versus during (April 2020–December 2022) the pandemic. Method Based on a preregistered analysis plan, we used cross-sectional data collected from 22,706 14–16-year-olds over 6 years (55% during the pandemic) in the Norwegian Mother, Father, and Child Cohort. We used measurement invariance analyses to compare the level of eating restraint and body concern before and during the pandemic, and multi-group structural equation models to estimate pre-pandemic and pandemic patterns of associations. Results Pandemic responders generally reported more eating problems than pre-pandemic responders, specifically on dieting and body dissatisfaction. However, after adjusting for a general linear increase in eating problems across all 6 years of data collection, the pandemic itself seems to be associated with more eating problems only among girls, reporting more eating restraints (meanΔ = 0.14 [CI: 0.07, 0.20]) and body concern (meanΔ = 0.17 [CI: 0.11, 0.23]). Associations between eating problems and a range of other characteristics did not differ across the pandemic and pre-pandemic groups. Conclusions There was a general increase in eating problems among 14–16-year-olds over time. Adjusting for this trend, the pandemic seems to exacerbate problems among girls. Although the mechanisms are unclear, our results point to factors susceptible to change that could have been intensified during the pandemic (e.g., screen time, mental distress). Our results highlight the importance of recognizing sex-specific differences in eating problems.

• Jensen, Pia; Madsen, Christian; Hauge, Lars Johan; Gustavson, Kristin; Lund, Ingunn Olea & Pettersen, Johanne Hagen [Vis alle 12 forfattere av denne artikkelen] (2023). Contact with primary care physicians among adults with pre-existing common mental health problems during the COVID-19 pandemic: a registry-based study from Norway. BMC Health Services Research. 23. doi: 10.1186/s12913-023-10108-3. Fulltekst i vitenarkiv Vis sammendrag

  Background During the COVID-19 pandemic, individuals with pre-existing mental health problems may have experienced additional stress, which could worsen symptoms or trigger relapse. Thus, this study aimed to investigate if the number of consultations with general practitioners (GPs) among individuals with a pre-existing common mental health problem during the pandemic differed from pre-pandemic years. Methods Data on consultations with GPs among 18–65-year-olds registered with common mental health problems in 2017–2021 were retrieved from the Norwegian Control and Payment of Health Reimbursements Database. Based on data from the pre-pandemic years (2017–2019), we predicted the number of consultations per week for depression, anxiety disorder, phobia/obsessive–compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and eating disorders during the pandemic (March 2020-December 2021) among individuals with pre-existing mental health problems. The forecasted and observed trends in GP consultations per week during the pandemic were stratified by diagnosis, gender, and age groups. Results The observed number of consultations for anxiety disorder, PTSD, and eating disorders were significantly higher than forecasted during extended periods of the two pandemic years. The differences were largest for PTSD (on average 37% higher in men and 47% higher in women during the pandemic), and for eating disorders among women (on average 87% higher during the pandemic). There were only minor differences between the predicted and observed number of consultations for depression and phobia/OCD. Conclusions During the pandemic, individuals with a recent history of mental health problems were more likely to seek help for anxiety disorder, PTSD, and eating disorders, as compared to pre-pandemic years.

• Slapø, Nora Berz; Nerland, Stener; Jørgensen, Kjetil Nordbø; Mørch-Johnsen, Lynn Egeland; Pettersen, Johanne Hagen & Roelfs, Daniel [Vis alle 22 forfattere av denne artikkelen] (2023). Auditory Cortex Thickness Is Associated With N100 Amplitude in Schizophrenia Spectrum Disorders. Schizophrenia Bulletin Open. 4(1). doi: 10.1093/schizbullopen/sgad015. Fulltekst i vitenarkiv Vis sammendrag

  Background and Hypothesis: The auditory cortex (AC) may play a central role in the pathophysiology of schizophrenia and auditory hallucinations (AH). Previous schizophrenia studies report thinner AC and impaired AC function, as indicated by decreased N100 amplitude of the auditory evoked potential. However, whether these structural and functional alterations link to AH in schizophrenia remain poorly understood. Study Design: Patients with a schizophrenia spectrum disorder (SCZspect), including patients with a lifetime experience of AH (AH+), without (AH−), and healthy controls underwent magnetic resonance imaging (39 SCZ spect, 22 AH+, 17 AH−, and 146 HC) and electroencephalography (33 SCZ spect, 17 AH+, 16 AH−, and 144 HC). Cortical thickness of the primary (AC1, Heschl’s gyrus) and secondary (AC2, Heschl’s sulcus, and the planum temporale) AC was compared between SCZ spect and controls and between AH+, AH−, and controls. To examine if the association between AC thickness and N100 amplitude differed between groups, we used regression models with interaction terms. Study Results: N100 amplitude was nominally smaller in SCZ spect (P = .03, d = 0.42) and in AH− (P = .020, d = 0.61), while AC2 was nominally thinner in AH+ (P = .02, d = 0.53) compared with controls. AC1 thickness was positively associated with N100 amplitude in SCZspect (t = 2.56, P = .016) and AH− (t= 3.18, P = .008), while AC2 thickness was positively associated with N100 amplitude in SCZspect (t = 2.37, P = .024) and in AH+ (t = 2.68, P = .019). Conclusions: The novel indings of positive associations between AC thickness and N100 amplitude in SCZ spect, suggest that a common neural substrate may underlie AC thickness and N100 amplitude alterations.

• Jensen, Pia; Engdahl, Bo Lars; Gustavson, Kristin; Lund, Ingunn Olea; Pettersen, Johanne Hagen & Madsen, Christian [Vis alle 12 forfattere av denne artikkelen] (2023). Incidence rates of treated mental disorders before and during the COVID-19 pandemic—a nationwide study comparing trends in the period 2015 to 2021. BMC Psychiatry. 23(1). doi: 10.1186/s12888-023-05157-1. Fulltekst i vitenarkiv Vis sammendrag

  Background There is a concern that exposure to psychosocial stressors during the COVID-19 pandemic may have led to a higher incidence of mental disorders. Thus, this study aimed to compare trends in incidence rates of depressive disorder, anxiety disorders, obsessive–compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and eating disorders in primary- and specialist health care before (2015–2019) and during the COVID-19 pandemic (2020–2021). Methods We used aggregated population registry data to calculate incidence rates of mental disorders from primary- (The Norwegian Control and Payment of Health Reimbursements Registry (KUHR)) and specialist (The Norwegian Patient Registry (NPR)) health care. The analyses included all Norwegian residents aged 18–65 during the study period. Incident cases were defined as having no previous registration with the same mental disorder in KUHR (from 2006) or NPR (from 2008). We used linear prediction models and mean models to compare incidence rates and test trends before and during the pandemic. Results During the pandemic, the incidence rates among women were higher or as predicted for OCD in specialist health care and for eating disorders in both primary- and specialist health care. These findings were strongest among women aged 18–24 years. Incidence rates for depression and phobia/OCD among both genders in primary health care and phobic anxiety disorders among both genders in specialist health care were lower or as predicted. Conclusion The COVID-19 pandemic may have led to more women needing treatment for OCD and eating disorders in the Norwegian population. The decreased incidence rates for some disorders might indicate that some individuals either avoided seeking help or had improved mental health during the pandemic.

Se alle arbeider i NVA

• Pettersen, Johanne Hagen; Hegemann, Laura Elizabeth; Bjuland, Knut Jørgen; Scheiene, Martin & Havdahl, Alexandra (2026). Loss of social communication skills and polygenic liabilities to neurodevelopmental conditions in the Norwegian MoBa cohort. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2026). Temporal trends in autism and ADHD. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2026). Hvorfor ser vi økning i autisme og ADHD diagnoser? Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Bjørndal, Ludvig Daae; Hannigan, Laurie John; Wootton, Robyn; Eek, Brandlistuen Ragnhild & Havdahl, Alexandra [Vis alle 8 forfattere av denne artikkelen] (2026). Anxiety in adolescents born 1999-2009: Temporal trends in diagnosis, symptoms, and expression of genetic liability. Fulltekst i vitenarkiv
• Askelund, Adrian Dahl & Pettersen, Johanne Hagen (2026). Workshop for Early-Career Researchers on Family-Based Genomic Analyses. Fulltekst i vitenarkiv Vis sammendrag

  This workshop provides introductory lectures and hands-on training in within-family and trio-based genetic methods, including trio polygenic score analyses, trio GWAS, genomic SEM, and intergenerational mendelian randomization. We also have short talks by early-career researchers with applications of these methods and keynote lectures from leading scientists reflecting on the past, present, and future of research in this field.

• Sanchez, Alejandra Martinez; Pettersen, Johanne Hagen; Scheiene, Martin; Bang, Lasse; Aase, Heidi & Bjuland, Knut Jørgen [Vis alle 9 forfattere av denne artikkelen] (2026). Time trends in autism diagnosis in Norway between 2010 and 2022. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Bjørndal, Ludvig Daae; Hannigan, Laurie John; Wootton, Robyn; Eek, Brandlistuen Ragnhild & Havdahl, Alexandra [Vis alle 8 forfattere av denne artikkelen] (2026). Temporal trends in adolescent anxiety diagnoses, symptoms, and expression of genetic liability. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Bjørndal, Ludvig Daae; Hannigan, Laurie John; Cheesman, Rosa Catherine Gillespie; Davies, Neil Martin & Andreassen, Ole [Vis alle 8 forfattere av denne artikkelen] (2026). Understanding the Rise in ADHD Diagnoses: Insights from the Norwegian Mother, Father, and Child Cohort Study. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Bjørndal, Ludvig Daae; Sanchez, Alejandra Martinez; Cheesman, Rosa Catherine Gillespie; Bishop, Somer & Bjuland, Knut Jørgen [Vis alle 11 forfattere av denne artikkelen] (2026). Exploring potential drivers of rising autism diagnoses in the Norwegian Mother, Father and Child Cohort Study (MoBa). Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2026). Hvorfor ser vi en økning i autismediagnoser? Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2025). Psykiske plager blant ungdommer under pandemien. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2025). Angst, depresjon og spiseproblemer blant ungdommer. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2025). Angst, depresjon og spiseproblemer blant ungdommer. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2025). Ungdom fikk flere psykiske plager under strenge tiltak og karantene. [Internet]. Psykologisk.no. Fulltekst i vitenarkiv
• Peng, Qiyuan; Pettersen, Johanne Hagen; Sunde, Hans Fredrik; Rietveld, Cornelius A. (Niels); Cheesman, Rosa Catherine Gillespie & Demange, Perline Aline Delle [Vis alle 11 forfattere av denne artikkelen] (2025). Intergenerational Transmission of Education in Norway: A Triangulation Approach. Fulltekst i vitenarkiv
• Peng, Qiyuan; Pettersen, Johanne Hagen; Sunde, Hans Fredrik; Rietveld, Cornelius A. (Niels); Cheesman, Rosa Catherine Gillespie & Demange, Perline Aline Delle [Vis alle 11 forfattere av denne artikkelen] (2025). Intergenerational Transmission of Education in Norway: A Triangulation Approach. Fulltekst i vitenarkiv Vis sammendrag

  The intergenerational transmission of education is a critical topic in social science. Substantial empirical evidence shows that children of highly educated parents often achieve higher levels of academic success than those of less-educated parents (Blanden et al., 2024; Björklund and Salvanes, 2011). Both environmental and genetic factors contribute to the association between parental and offspring educational attainment. However, existing empirical research often conflates these effects due to methodological differences and data limitations, making the results challenging to interpret and sometimes yielding conflicting conclusions (Atav et al., 2024). These limitations restrict insights to intergenerational correlations rather than establishing causal effects. Our study addresses this gap by employing a triangulation approach, integrating multiple methods with distinct strengths and biases to examine whether parental education causally impacts offspring’s educational achievement. Specifically, by leveraging parent-child trios’ register data from Statistics Norway and genetic data from the Norwegian Mother, Father, and Child Cohort Study (MoBa), we apply multivariable regression analysis, entropy balancing, adoption design, and within-family Mendelian randomization to explore the causal relationship between parental educational attainment and offspring’s educational achievement (grade point average, GPA) in Norway. Our preliminary findings suggest a causal effect of parental educational attainment on offspring’s academic success during adolescence, with variations between maternal and paternal influences and differential effects by offspring sex. By isolating genetic confounders, this study enhances our understanding of the causal pathways in intergenerational educational transmission, offering valuable insights for addressing educational inequalities.

• Pettersen, Johanne Hagen & Ask, Helga (2024). Direct and Indirect Genetic Influences on Mental Distress in Mother-Father-Offspring Trios. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2024). Psykisk helse i familier under Covid-19 nedstengningen: Hvordan påvirket familiemedlemmer hverandre? Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2024). Direct and indirect genetic influences on mental distress in mother-father-offspring trios during the Covid-19 lockdown. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen & Ask, Helga (2024). Direct and Indirect Genetic Influences on Mental Distress in Mother-Father-Offspring Trios. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2024). Spiseproblemer blant ungdommer før og under Covid-19 pandemien. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2024). Mer psykiske plager blant unge under og etter karantene. [Internet]. FHI.no. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2024). FHI: Unge hadde mer psykiske plager under og etter covid-karantene. [Internet]. VG.no. Fulltekst i vitenarkiv
• Hegemann, Laura; Eilertsen, Espen Moen; Pettersen, Johanne Hagen; Corfield, Elizabeth Claire; Cheesman, Rosa Catherine Gillespie & Frach, Leonard [Vis alle 11 forfattere av denne artikkelen] (2024). Direct and Indirect Genetic Effects on Early Neurodevelopmental Traits (updated results). Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Eilertsen, Espen Moen; Hegemann, Laura; Hannigan, Laurie John; Lund, Ingunn Olea & Jensen, Pia [Vis alle 12 forfattere av denne artikkelen] (2024). Direct and indirect genetic inluences on mental distress in mother-father-offspring trios during the Covid-19 lockdown. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2024). Psykisk helse blant ungdommer under pandemien. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Hegemann, Laura; Gustavson, Kristin; Lund, Ingunn Olea; Jensen, Pia & Nesvåg, Ragnar [Vis alle 10 forfattere av denne artikkelen] (2023). Eating problems among adolescents before and during the Covid-19 pandemic. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Hegemann, Laura; Gustavson, Kristin; Lund, Ingunn Olea; Jensen, Pia & Nesvåg, Ragnar [Vis alle 10 forfattere av denne artikkelen] (2023). Eating problems among adolescents before and during the Covid-19 pandemic. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen & Ask, Helga (2023). Eating problems among adolescents before and during the Covid-19 pandemic. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen & Ask, Helga (2023). Eating problems among adolescents before and during the Covid-19 pandemic. Fulltekst i vitenarkiv
• Jensen, Pia; Engdahl, Bo Lars; Gustavson, Kristin; Lund, Ingunn Olea; Pettersen, Johanne Hagen & Madsen, Christian [Vis alle 12 forfattere av denne artikkelen] (2023). Erratum: Correction: Incidence rates of treated mental disorders before and during the COVID-19 pandemic-a nationwide study comparing trends in the period 2015 to 2021 (BMC psychiatry (2023) 23 1 (668)). BMC Psychiatry. 23(1), s. 874–874. doi: 10.1186/s12888-023-05367-7. Fulltekst i vitenarkiv
• Ask, Helga; Pettersen, Johanne Hagen & Jensen, Pia (2022). Pandemien og den psykiske folkehelsen. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen (2022). Pandemiens effekt på barn og unges psykiske helse. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Hannigan, Laurie John; Eilertsen, Espen Moen; Gustavson, Kristin; Lund, Ingunn Olea & Jensen, Pia [Vis alle 10 forfattere av denne artikkelen] (2022). Indirect genetic influences on mental distress in mother-father-offspring trios during the covid-19 lockdown. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Hannigan, Laurie John; Gustavson, Kristin; Lund, Ingunn Olea; Jensen, Pia & Nesvåg, Ragnar [Vis alle 8 forfattere av denne artikkelen] (2022). Factors associated with change in adolescent mental distress during the first year of the Covid-19 pandemic. Fulltekst i vitenarkiv
• Jensen, Pia; Madsen, Christian; Hauge, Lars Johan; Gustavson, Kristin; Lund, Ingunn Olea & Pettersen, Johanne Hagen [Vis alle 12 forfattere av denne artikkelen] (2022). Mental health treatment among adults with pre-existing mental disorders during the COVID-19 pandemic: a registry-based study from Norway. Fulltekst i vitenarkiv
• Pettersen, Johanne Hagen; Ask, Helga & Brandlistuen, Ragnhild Eek (2022). Covid-19 and impact on mental health. Fulltekst i vitenarkiv
• Aase, Heidi; Pettersen, Johanne Hagen; Bang, Lasse; Havdahl, Alexandra & Biele, Guido (2025). Del 4: Tidstrender i forekomst av ADHD-diagnoser - FHI. Folkehelseinstituttet. Fulltekst i vitenarkiv Vis sammendrag

  Andelen barn og unge i befolkningen som får en ADHD-diagnose har økt kraftig etter 2018. Økningen var særlig uttalt i årene 2020-2022, under covid-19 pandemien. Det er spesielt blant jenter i slutten av tenårene og blant unge kvinner at forekomsten av nye diagnoser øker. Vi ser samtidig store sosiale og geografiske forskjeller i forekomsten av ADHD-diagnoser, men mønstrene er ulike de vi ser for autisme.

• Hegemann, Laura; Eilertsen, Espen Moen; Pettersen, Johanne Hagen; Corfield, Elizabeth Claire; Cheesman, Rosa Catherine Gillespie & Frach, Leonard [Vis alle 11 forfattere av denne artikkelen] (2025). Direct and Indirect Genetic Effects on Early Neurodevelopmental Traits (preprint). MedRxiv. Fulltekst i vitenarkiv
• Sanchez, Alejandra Martinez; Pettersen, Johanne Hagen; Bang, Lasse; Bjuland, Knut Jørgen; Scheiene, Martin & Aase, Heidi [Vis alle 7 forfattere av denne artikkelen] (2025). Thematic Issue of the Public Health Report 2025 – Mental Health of Children and Adolescents; Chapter 3: Time Trends in the Prevalence of Autism Diagnoses. Folkehelseinstituttet. doi: https:/www.fhi.no/contentassets/b5b3603ec4794c5cb0c8651589b359f8/temautgave-barn-og-unges-psykiske-helse_2025.pdf. Fulltekst i vitenarkiv

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