Publication list - Publika - Scientific publications from Oslo University Hospital

Publications by Gun Peggy Strømstad Knudsen

104 publications found

Original articles

Rørtveit G, Knudsen GPS (2024)
[Not Available]
Tidsskr Nor Laegeforen, 144 (5)
DOI 10.4045/tidsskr.24.0102, PubMed 38651720

Qu HQ, Connolly JJ, Kraft P, Long J, Pereira A, Flatley C, Turman C, Prins B, Mentch F, Lotufo PA, Magnus P, Stampfer MJ, Tamimi R, Eliassen AH, Zheng W, Knudsen GPS, Helgeland O, Butterworth AS, Hakonarson H, Sleiman PM, IHCC consortium (2023)
Trans-ethnic polygenic risk scores for body mass index: An international hundred K+ cohorts consortium study
Clin Transl Med, 13 (6), e1291
DOI 10.1002/ctm2.1291, PubMed 37337639

Engel SM, Villanger GD, Herring A, Nethery RC, Drover SSM, Zoeller RT, Meltzer HM, Zeiner P, Knudsen GP, Reichborn-Kjennerud T, Longnecker MP, Aase H (2022)
Gestational thyroid hormone concentrations and risk of attention-deficit hyperactivity disorder in the Norwegian Mother, Father and Child Cohort Study
Paediatr Perinat Epidemiol, 37 (3), 218-228
DOI 10.1111/ppe.12941, PubMed 36482860

Helgeland Ø, Vaudel M, Sole-Navais P, Flatley C, Juodakis J, Bacelis J, Koløen IL, Knudsen GP, Johansson BB, Magnus P, Kjennerud TR, Juliusson PB, Stoltenberg C, Holmen OL, Andreassen OA, Jacobsson B, Njølstad PR, Johansson S (2022)
Characterization of the genetic architecture of infant and early childhood body mass index
Nat Metab, 4 (3), 344-358
DOI 10.1038/s42255-022-00549-1, PubMed 35315439

Tverdal A, Høiseth G, Magnus P, Næss Ø, Selmer R, Knudsen GP, Mørland J (2021)
Alcohol Consumption, HDL-Cholesterol and Incidence of Colon and Rectal Cancer: A Prospective Cohort Study Including 250,010 Participants
Alcohol Alcohol, 56 (6), 718-725
DOI 10.1093/alcalc/agab007, PubMed 33604595

Watson HJ, Thornton LM, Yilmaz Z, Baker JH, Coleman JRI, Adan RAH, Alfredsson L, Andreassen OA, Ask H, Berrettini WH, Boehnke M, Boehm I, Boni C, Buehren K, Bulant J, Burghardt R, Chang X, Cichon S, Cone RD, Courtet P, Crow S, Crowley JJ, Danner UN, de Zwaan M, Dedoussis G et al. (2021)
Common Genetic Variation and Age of Onset of Anorexia Nervosa
Biol Psychiatry Glob Open Sci, 2 (4), 368-378
DOI 10.1016/j.bpsgos.2021.09.001, PubMed 36324647

Ip HF, van der Laan CM, Krapohl EML, Brikell I, Sánchez-Mora C, Nolte IM, St Pourcain B, Bolhuis K, Palviainen T, Zafarmand H, Colodro-Conde L, Gordon S, Zayats T, Aliev F, Jiang C, Wang CA, Saunders G, Karhunen V, Hammerschlag AR, Adkins DE, Border R, Peterson RE, Prinz JA, Thiering E, Seppälä I et al. (2021)
Genetic association study of childhood aggression across raters, instruments, and age
Transl Psychiatry, 11 (1), 413
DOI 10.1038/s41398-021-01480-x, PubMed 34330890

Kamai EM, Villanger GD, Nethery RC, Thomsen C, Sakhi AK, Drover SSM, Hoppin JA, Knudsen GP, Reichborn-Kjennerud T, Zeiner P, Overgaard K, Herring AH, Aase H, Engel SM (2021)
Gestational Phthalate Exposure and Preschool Attention Deficit Hyperactivity Disorder in Norway
Environ Epidemiol, 5 (4), e161
DOI 10.1097/EE9.0000000000000161, PubMed 34414345

Choi G, Villanger GD, Drover SSM, Sakhi AK, Thomsen C, Nethery RC, Zeiner P, Knudsen GP, Reichborn-Kjennerud T, Øvergaard KR, Herring AH, Skogan AH, Biele G, Aase H, Engel SM (2021)
Prenatal phthalate exposures and executive function in preschool children
Environ Int, 149, 106403
DOI 10.1016/j.envint.2021.106403, PubMed 33524667

Smajlagić D, Lavrichenko K, Berland S, Helgeland Ø, Knudsen GP, Vaudel M, Haavik J, Knappskog PM, Njølstad PR, Houge G, Johansson S (2020)
Population prevalence and inheritance pattern of recurrent CNVs associated with neurodevelopmental disorders in 12,252 newborns and their parents
Eur J Hum Genet, 29 (1), 205-215
DOI 10.1038/s41431-020-00707-7, PubMed 32778765

Munn-Chernoff MA, Johnson EC, Chou YL, Coleman JRI, Thornton LM, Walters RK, Yilmaz Z, Baker JH, Hübel C, Gordon S, Medland SE, Watson HJ, Gaspar HA, Bryois J, Hinney A, Leppä VM, Mattheisen M, Ripke S, Yao S, Giusti-Rodríguez P, Hanscombe KB, Adan RAH, Alfredsson L, Ando T, Andreassen OA et al. (2020)
Shared genetic risk between eating disorder- and substance-use-related phenotypes: Evidence from genome-wide association studies
Addict Biol, 26 (1), e12880
DOI 10.1111/adb.12880, PubMed 32064741

O'Connell KS, Shadrin A, Smeland OB, Bahrami S, Frei O, Bettella F, Krull F, Fan CC, Askeland RB, Knudsen GPS, Halmøy A, Steen NE, Ueland T, Walters GB, Davíðsdóttir K, Haraldsdóttir GS, Guðmundsson ÓÓ, Stefánsson H, Reichborn-Kjennerud T, Haavik J, Dale AM, Stefánsson K, Djurovic S, Andreassen OA (2019)
Identification of Genetic Loci Shared Between Attention-Deficit/Hyperactivity Disorder, Intelligence, and Educational Attainment
Biol Psychiatry, 87 (12), 1052-1062
DOI 10.1016/j.biopsych.2019.11.015, PubMed 32061372

Gudmundsson OO, Walters GB, Ingason A, Johansson S, Zayats T, Athanasiu L, Sonderby IE, Gustafsson O, Nawaz MS, Jonsson GF, Jonsson L, Knappskog PM, Ingvarsdottir E, Davidsdottir K, Djurovic S, Knudsen GPS, Askeland RB, Haraldsdottir GS, Baldursson G, Magnusson P, Sigurdsson E, Gudbjartsson DF, Stefansson H, Andreassen OA, Haavik J et al. (2019)
Attention-deficit hyperactivity disorder shares copy number variant risk with schizophrenia and autism spectrum disorder
Transl Psychiatry, 9 (1), 258
DOI 10.1038/s41398-019-0599-y, PubMed 31624239

Helgeland Ø, Vaudel M, Juliusson PB, Lingaas Holmen O, Juodakis J, Bacelis J, Jacobsson B, Lindekleiv H, Hveem K, Lie RT, Knudsen GP, Stoltenberg C, Magnus P, Sagen JV, Molven A, Johansson S, Njølstad PR (2019)
Genome-wide association study reveals dynamic role of genetic variation in infant and early childhood growth
Nat Commun, 10 (1), 4448
DOI 10.1038/s41467-019-12308-0, PubMed 31575865

Watson HJ, Yilmaz Z, Thornton LM, Hübel C, Coleman JRI, Gaspar HA, Bryois J, Hinney A, Leppä VM, Mattheisen M, Medland SE, Ripke S, Yao S, Giusti-Rodríguez P, Anorexia Nervosa Genetics Initiative, Hanscombe KB, Purves KL, Eating Disorders Working Group of the Psychiatric Genomics Consortium, Adan RAH, Alfredsson L, Ando T, Andreassen OA, Baker JH, Berrettini WH, Boehm I et al. (2019)
Genome-wide association study identifies eight risk loci and implicates metabo-psychiatric origins for anorexia nervosa
Nat Genet, 51 (8), 1207-1214
DOI 10.1038/s41588-019-0439-2, PubMed 31308545

Gustavson K, Ask H, Ystrom E, Stoltenberg C, Lipkin WI, Surén P, Håberg SE, Magnus P, Knudsen GP, Eilertsen E, Bresnahan M, Aase H, Mjaaland S, Susser ES, Hornig M, Reichborn-Kjennerud T (2019)
Maternal fever during pregnancy and offspring attention deficit hyperactivity disorder
Sci Rep, 9 (1), 9519
DOI 10.1038/s41598-019-45920-7, PubMed 31266998

Watson HJ, Diemer EW, Zerwas S, Gustavson K, Knudsen GP, Torgersen L, Reichborn-Kjennerud T, Bulik CM (2019)
Prenatal and perinatal risk factors for eating disorders in women: A population cohort study
Int J Eat Disord, 52 (6), 643-651
DOI 10.1002/eat.23073, PubMed 30891792

Huckins LM, Hatzikotoulas K, Southam L, Thornton LM, Steinberg J, Aguilera-McKay F, Treasure J, Schmidt U, Gunasinghe C, Romero A, Curtis C, Rhodes D, Moens J, Kalsi G, Dempster D, Leung R, Keohane A, Burghardt R, Ehrlich S, Hebebrand J, Hinney A, Ludolph A, Walton E, Deloukas P, Hofman A et al. (2018)
Correction: Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa
Mol Psychiatry, 23 (9), 1969
DOI 10.1038/mp.2017.202, PubMed 30420737

Engel SM, Villanger GD, Nethery RC, Thomsen C, Sakhi AK, Drover SSM, Hoppin JA, Zeiner P, Knudsen GP, Reichborn-Kjennerud T, Herring AH, Aase H (2018)
Prenatal Phthalates, Maternal Thyroid Function, and Risk of Attention-Deficit Hyperactivity Disorder in the Norwegian Mother and Child Cohort
Environ Health Perspect, 126 (5), 057004
DOI 10.1289/EHP2358, PubMed 29790729

Gillespie NA, Aggen SH, Neale MC, Knudsen GP, Krueger RF, South SC, Czajkowski N, Nesvåg R, Ystrom E, Kendler KS, Reichborn-Kjennerud T (2018)
Associations between personality disorders and cannabis use and cannabis use disorder: a population-based twin study
Addiction, 113 (8), 1488-1498
DOI 10.1111/add.14209, PubMed 29500852

Czajkowski N, Aggen SH, Krueger RF, Kendler KS, Neale MC, Knudsen GP, Gillespie NA, Røysamb E, Tambs K, Reichborn-Kjennerud T (2018)
A Twin Study of Normative Personality and DSM-IV Personality Disorder Criterion Counts: Evidence for Separate Genetic Influences
Am J Psychiatry, 175 (7), 649-656
DOI 10.1176/appi.ajp.2017.17050493, PubMed 29558815

Gustavson K, Knudsen AK, Nesvåg R, Knudsen GP, Vollset SE, Reichborn-Kjennerud T (2018)
Prevalence and stability of mental disorders among young adults: findings from a longitudinal study
BMC Psychiatry, 18 (1), 65
DOI 10.1186/s12888-018-1647-5, PubMed 29530018

Welander-Vatn A, Torvik FA, Czajkowski N, Kendler KS, Reichborn-Kjennerud T, Knudsen GP, Ystrom E (2018)
Relationships Among Avoidant Personality Disorder, Social Anxiety Disorder, and Normative Personality Traits: A Twin Study
J Pers Disord, 33 (3), 289-309
DOI 10.1521/pedi_2018_32_341, PubMed 29505386

Giannese F, Luchetti A, Barbiera G, Lampis V, Zanettini C, Knudsen GP, Scaini S, Lazarevic D, Cittaro D, D'Amato FR, Battaglia M (2018)
Conserved DNA Methylation Signatures in Early Maternal Separation and in Twins Discordant for CO₂ Sensitivity
Sci Rep, 8 (1), 2258
DOI 10.1038/s41598-018-20457-3, PubMed 29396481

Gillespie NA, Aggen SH, Gentry AE, Neale MC, Knudsen GP, Krueger RF, South SC, Czajkowski N, Nesvåg R, Ystrom E, Rosenström TH, Torvik FA, Reichborn-Kjennerud T, Kendler KS (2018)
Testing Genetic and Environmental Associations Between Personality Disorders and Cocaine Use: A Population-Based Twin Study
Twin Res Hum Genet, 21 (1), 24-32
DOI 10.1017/thg.2017.73, PubMed 29369040

Ystrom E, Gustavson K, Brandlistuen RE, Knudsen GP, Magnus P, Susser E, Davey Smith G, Stoltenberg C, Surén P, Håberg SE, Hornig M, Lipkin WI, Nordeng H, Reichborn-Kjennerud T (2017)
Prenatal Exposure to Acetaminophen and Risk of ADHD
Pediatrics, 140 (5)
DOI 10.1542/peds.2016-3840, PubMed 29084830

Eilertsen EM, Gjerde LC, Reichborn-Kjennerud T, Ørstavik RE, Knudsen GP, Stoltenberg C, Czajkowski N, Røysamb E, Kendler KS, Ystrom E (2017)
Maternal alcohol use during pregnancy and offspring attention-deficit hyperactivity disorder (ADHD): a prospective sibling control study
Int J Epidemiol, 46 (5), 1633-1640
DOI 10.1093/ije/dyx067, PubMed 28449133

Olafsson S, Stridh P, Bos SD, Ingason A, Euesden J, Sulem P, Thorleifsson G, Gustafsson O, Johannesson A, Geirsson AJ, Thorsson AV, Sigurgeirsson B, Ludviksson BR, Olafsson E, Kristjansdottir H, Jonasson JG, Olafsson JH, Orvar KB, Benediktsson R, Bjarnason R, Kristjansdottir S, Gislason T, Valdimarsson T, Mikaelsdottir E, Sigurdsson S et al. (2017)
Fourteen sequence variants that associate with multiple sclerosis discovered by meta-analysis informed by genetic correlations
NPJ Genom Med, 2, 24
DOI 10.1038/s41525-017-0027-2, PubMed 29263835

Huckins LM, Hatzikotoulas K, Southam L, Thornton LM, Steinberg J, Aguilera-McKay F, Treasure J, Schmidt U, Gunasinghe C, Romero A, Curtis C, Rhodes D, Moens J, Kalsi G, Dempster D, Leung R, Keohane A, Burghardt R, Ehrlich S, Hebebrand J, Hinney A, Ludolph A, Walton E, Deloukas P, Hofman A et al. (2017)
Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa
Mol Psychiatry, 23 (5), 1169-1180
DOI 10.1038/mp.2017.88, PubMed 29155802

Watson HJ, Zerwas S, Torgersen L, Gustavson K, Diemer EW, Knudsen GP, Reichborn-Kjennerud T, Bulik CM (2017)
Maternal eating disorders and perinatal outcomes: A three-generation study in the Norwegian Mother and Child Cohort Study
J Abnorm Psychol, 126 (5), 552-564
DOI 10.1037/abn0000241, PubMed 28691845

Seglem KB, Ørstavik R, Torvik FA, Gjerde LC, Røysamb E, Reichborn-Kjennerud T, Knudsen GP, Tambs K (2017)
Pre-pregnancy mental distress and musculoskeletal pain and sickness absence during pregnancy - a twin cohort study
Eur J Public Health, 27 (3), 477-481
DOI 10.1093/eurpub/ckw267, PubMed 28175262

Torvik FA, Rosenström TH, Ystrom E, Tambs K, Røysamb E, Czajkowski N, Gillespie N, Knudsen GP, Kendler KS, Reichborn-Kjennerud T (2017)
Stability and change in etiological factors for alcohol use disorder and major depression
J Abnorm Psychol, 126 (6), 812-822
DOI 10.1037/abn0000280, PubMed 28541064

Nesvåg R, Reichborn-Kjennerud T, Gillespie NA, Knudsen GP, Bramness JG, Kendler KS, Ystrom E (2017)
Genetic and Environmental Contributions to the Association Between Cannabis Use and Psychotic-Like Experiences in Young Adult Twins
Schizophr Bull, 43 (3), 644-653
DOI 10.1093/schbul/sbw101, PubMed 27431873

Villanger GD, Learner E, Longnecker MP, Ask H, Aase H, Zoeller RT, Knudsen GP, Reichborn-Kjennerud T, Zeiner P, Engel SM (2017)
Effects of Sample Handling and Analytical Procedures on Thyroid Hormone Concentrations in Pregnant Women's Plasma
Epidemiology, 28 (3), 365-369
DOI 10.1097/EDE.0000000000000606, PubMed 27984425

Reichborn-Kjennerud T, Krueger RF, Ystrom E, Torvik FA, Rosenström TH, Aggen SH, South SC, Neale MC, Knudsen GP, Kendler KS, Czajkowski NO (2017)
Do DSM-5 Section II personality disorders and Section III personality trait domains reflect the same genetic and environmental risk factors?
Psychol Med, 47 (12), 2205-2215
DOI 10.1017/S0033291717000824, PubMed 28414014

Nesvåg R, Jönsson EG, Bakken IJ, Knudsen GP, Bjella TD, Reichborn-Kjennerud T, Melle I, Andreassen OA (2017)
The quality of severe mental disorder diagnoses in a national health registry as compared to research diagnoses based on structured interview
BMC Psychiatry, 17 (1), 93
DOI 10.1186/s12888-017-1256-8, PubMed 28292279

Long EC, Aggen SH, Neale MC, Knudsen GP, Krueger RF, South SC, Czajkowski N, Nesvåg R, Ystrom E, Torvik FA, Kendler KS, Gillespie NA, Reichborn-Kjennerud T (2017)
The association between personality disorders with alcohol use and misuse: A population-based twin study
Drug Alcohol Depend, 174, 171-180
DOI 10.1016/j.drugalcdep.2017.01.022, PubMed 28334662

Gustavson K, Ystrom E, Stoltenberg C, Susser E, Surén P, Magnus P, Knudsen GP, Smith GD, Langley K, Rutter M, Aase H, Reichborn-Kjennerud T (2017)
Smoking in Pregnancy and Child ADHD
Pediatrics, 139 (2)
DOI 10.1542/peds.2016-2509, PubMed 28138005

South SC, Krueger RF, Knudsen GP, Ystrom E, Czajkowski N, Aggen SH, Neale MC, Gillespie NA, Kendler KS, Reichborn-Kjennerud T (2016)
A population based twin study of DSM-5 maladaptive personality domains
Personal Disord, 8 (4), 366-375
DOI 10.1037/per0000220, PubMed 27797545

Aarem J, Brunborg G, Aas KK, Harbak K, Taipale MM, Magnus P, Knudsen GP, Duale N (2016)
Comparison of blood RNA isolation methods from samples stabilized in Tempus tubes and stored at a large human biobank
BMC Res Notes, 9 (1), 430
DOI 10.1186/s13104-016-2224-y, PubMed 27587079

Østby KA, Czajkowski N, Knudsen GP, Ystrøm E, Gjerde LC, Kendler KS, Ørstavik RE, Reichborn-Kjennerud T (2016)
Does low alcohol use increase the risk of sickness absence? A discordant twin study
BMC Public Health, 16 (1), 825
DOI 10.1186/s12889-016-3502-2, PubMed 27538396

Torvik FA, Reichborn-Kjennerud T, Gjerde LC, Knudsen GP, Ystrom E, Tambs K, Røysamb E, Østby K, Ørstavik R (2016)
Mood, anxiety, and alcohol use disorders and later cause-specific sick leave in young adult employees
BMC Public Health, 15, 702
DOI 10.1186/s12889-016-3427-9, PubMed 27488425

Kendler KS, Aggen SH, Gillespie N, Neale MC, Knudsen GP, Krueger RF, Czajkowski N, Ystrom E, Reichborn-Kjennerud T (2016)
The Genetic and Environmental Sources of Resemblance Between Normative Personality and Personality Disorder Traits
J Pers Disord, 31 (2), 193-207
DOI 10.1521/pedi_2016_30_251, PubMed 27322578

Sheerin C, Berenz EC, Knudsen GP, Reichborn-Kjennerud T, Kendler KS, Aggen SH, Amstadter AB (2016)
A population-based study of help seeking and self-medication among trauma-exposed individuals
Psychol Addict Behav, 30 (7), 771-777
DOI 10.1037/adb0000185, PubMed 27269293

Magnus P, Birke C, Vejrup K, Haugan A, Alsaker E, Daltveit AK, Handal M, Haugen M, Høiseth G, Knudsen GP, Paltiel L, Schreuder P, Tambs K, Vold L, Stoltenberg C (2016)
Cohort Profile Update: The Norwegian Mother and Child Cohort Study (MoBa)
Int J Epidemiol, 45 (2), 382-8
DOI 10.1093/ije/dyw029, PubMed 27063603

Torvik FA, Welander-Vatn A, Ystrom E, Knudsen GP, Czajkowski N, Kendler KS, Reichborn-Kjennerud T (2015)
Longitudinal associations between social anxiety disorder and avoidant personality disorder: A twin study
J Abnorm Psychol, 125 (1), 114-124
DOI 10.1037/abn0000124, PubMed 26569037

Welander-Vatn A, Ystrom E, Tambs K, Neale MC, Kendler KS, Reichborn-Kjennerud T, Knudsen GP (2015)
The relationship between anxiety disorders and dimensional representations of DSM-IV personality disorders: A co-twin control study
J Affect Disord, 190, 349-356
DOI 10.1016/j.jad.2015.09.038, PubMed 26544619

Gjerde LC, Czajkowski N, Røysamb E, Ystrom E, Tambs K, Aggen SH, Ørstavik RE, Kendler KS, Reichborn-Kjennerud T, Knudsen GP (2015)
A longitudinal, population-based twin study of avoidant and obsessive-compulsive personality disorder traits from early to middle adulthood
Psychol Med, 45 (16), 3539-48
DOI 10.1017/S0033291715001440, PubMed 26273730

Reichborn-Kjennerud T, Czajkowski N, Ystrøm E, Ørstavik R, Aggen SH, Tambs K, Torgersen S, Neale MC, Røysamb E, Krueger RF, Knudsen GP, Kendler KS (2015)
A longitudinal twin study of borderline and antisocial personality disorder traits in early to middle adulthood
Psychol Med, 45 (14), 3121-31
DOI 10.1017/S0033291715001117, PubMed 26050739

Zayats T, Athanasiu L, Sonderby I, Djurovic S, Westlye LT, Tamnes CK, Fladby T, Aase H, Zeiner P, Reichborn-Kjennerud T, Knappskog PM, Knudsen GP, Andreassen OA, Johansson S, Haavik J (2015)
Genome-wide analysis of attention deficit hyperactivity disorder in Norway
PLoS One, 10 (4), e0122501
DOI 10.1371/journal.pone.0122501, PubMed 25875332

Steinberg S, Stefansson H, Jonsson T, Johannsdottir H, Ingason A, Helgason H, Sulem P, Magnusson OT, Gudjonsson SA, Unnsteinsdottir U, Kong A, Helisalmi S, Soininen H, Lah JJ, DemGene, Aarsland D, Fladby T, Ulstein ID, Djurovic S, Sando SB, White LR, Knudsen GP, Westlye LT, Selbæk G, Giegling I et al. (2015)
Loss-of-function variants in ABCA7 confer risk of Alzheimer's disease
Nat Genet, 47 (5), 445-7
DOI 10.1038/ng.3246, PubMed 25807283

Guidry VT, Longnecker MP, Aase H, Eggesbø M, Zeiner P, Reichborn-Kjennerud T, Knudsen GP, Bertelsen RJ, Ye X, Calafat AM, Engel SM (2015)
Measurement of Total and Free Urinary Phenol and Paraben Concentrations over the Course of Pregnancy: Assessing Reliability and Contamination of Specimens in the Norwegian Mother and Child Cohort Study
Environ Health Perspect, 123 (7), 705-11
DOI 10.1289/ehp.1408325, PubMed 25782115

Nesvåg R, Knudsen GP, Bakken IJ, Høye A, Ystrom E, Surén P, Reneflot A, Stoltenberg C, Reichborn-Kjennerud T (2015)
Substance use disorders in schizophrenia, bipolar disorder, and depressive illness: a registry-based study
Soc Psychiatry Psychiatr Epidemiol, 50 (8), 1267-76
DOI 10.1007/s00127-015-1025-2, PubMed 25680837

Torvik FA, Ystrom E, Czajkowski N, Tambs K, Røysamb E, Ørstavik R, Knudsen GP, Kendler KS, Reichborn-Kjennerud T (2015)
Socioeconomic status and sick leave granted for mental and somatic disorders: a prospective study of young adult twins
BMC Public Health, 15, 134
DOI 10.1186/s12889-015-1457-3, PubMed 25884296

Strand BH, Rosness TA, Engedal K, Magnus P, Bergem AL, Schirmer H, Bjertness E, Knudsen GP (2015)
Interaction of Apolipoprotein E Genotypes, Lifestyle Factors and Future Risk of Dementia-Related Mortality: The Cohort of Norway (CONOR)
Dement Geriatr Cogn Disord, 40 (3-4), 137-47
DOI 10.1159/000431218, PubMed 26088392

Orstavik RE, Czajkowski N, Røysamb E, Knudsen GP, Tambs K, Reichborn-Kjennerud T (2014)
Sex differences in genetic and environmental influences on educational attainment and income
Twin Res Hum Genet, 17 (6), 516-25
DOI 10.1017/thg.2014.68, PubMed 25431286

Kendler KS, Aggen SH, Neale MC, Knudsen GP, Krueger RF, Tambs K, Czajkowski N, Ystrom E, Ørstavik RE, Reichborn-Kjennerud T (2014)
A longitudinal twin study of cluster A personality disorders
Psychol Med, 45 (7), 1531-8
DOI 10.1017/S0033291714002669, PubMed 25394477

Brown RC, Berenz EC, Aggen SH, Gardner CO, Knudsen GP, Reichborn-Kjennerud T, Kendler KS, Amstadter AB (2014)
Trauma Exposure and Axis I Psychopathology: A Co-twin Control Analysis in Norwegian Young Adults
Psychol Trauma, 6 (6), 652-660
DOI 10.1037/a0034326, PubMed 25544868

Bakken IJ, Revdal E, Nesvåg R, Brenner E, Knudsen GP, Surén P, Ghaderi S, Gunnes N, Magnus P, Reichborn-Kjennerud T, Camilla Stoltenberg, Trogstad LI, Håberg SE, Brodtkorb E (2014)
Substance use disorders and psychotic disorders in epilepsy: a population-based registry study
Epilepsy Res, 108 (8), 1435-43
DOI 10.1016/j.eplepsyres.2014.06.021, PubMed 25062893

Torvik FA, Gjerde LC, Røysamb E, Tambs K, Kendler KS, Czajkowski NO, Knudsen GP, Reichborn-Kjennerud T, Ørstavik RE (2014)
Genetic and environmental contributions to the relationship between internalizing disorders and sick leave granted for mental and somatic disorders
Twin Res Hum Genet, 17 (4), 225-35
DOI 10.1017/thg.2014.27, PubMed 24823276

Østby KA, Czajkowski N, Knudsen GP, Ystrom E, Gjerde LC, Kendler KS, Ørstavik RE, Reichborn-Kjennerud T (2014)
Personality disorders are important risk factors for disability pensioning
Soc Psychiatry Psychiatr Epidemiol, 49 (12), 2003-11
DOI 10.1007/s00127-014-0878-0, PubMed 24791656

Jansen MD, Knudsen GP, Myhre R, Høiseth G, Mørland J, Næss Ø, Tambs K, Magnus P (2014)
Genetic variants in loci 1p13 and 9p21 and fatal coronary heart disease in a Norwegian case-cohort study
Mol Biol Rep, 41 (5), 2733-43
DOI 10.1007/s11033-014-3096-7, PubMed 24728607

Boraska V, Franklin CS, Floyd JA, Thornton LM, Huckins LM, Southam L, Rayner NW, Tachmazidou I, Klump KL, Treasure J, Lewis CM, Schmidt U, Tozzi F, Kiezebrink K, Hebebrand J, Gorwood P, Adan RA, Kas MJ, Favaro A, Santonastaso P, Fernández-Aranda F, Gratacos M, Rybakowski F, Dmitrzak-Weglarz M, Kaprio J et al. (2014)
A genome-wide association study of anorexia nervosa
Mol Psychiatry, 19 (10), 1085-94
DOI 10.1038/mp.2013.187, PubMed 24514567

Gjerde LC, Røysamb E, Czajkowski N, Knudsen GP, Ostby K, Tambs K, Kendler KS, Reichborn-Kjennerud T, Orstavik RE (2014)
Personality disorders and long-term sick leave: a population-based study of young adult Norwegian twins
Twin Res Hum Genet, 17 (1), 1-9
DOI 10.1017/thg.2013.90, PubMed 24417773

Bertelsen RJ, Engel SM, Jusko TA, Calafat AM, Hoppin JA, London SJ, Eggesbø M, Aase H, Zeiner P, Reichborn-Kjennerud T, Knudsen GP, Guidry VT, Longnecker MP (2014)
Reliability of triclosan measures in repeated urine samples from Norwegian pregnant women
J Expo Sci Environ Epidemiol, 24 (5), 517-21
DOI 10.1038/jes.2013.95, PubMed 24472755

Reichborn-Kjennerud T, Ystrom E, Neale MC, Aggen SH, Mazzeo SE, Knudsen GP, Tambs K, Czajkowski NO, Kendler KS (2013)
Structure of genetic and environmental risk factors for symptoms of DSM-IV borderline personality disorder
JAMA Psychiatry, 70 (11), 1206-14
DOI 10.1001/jamapsychiatry.2013.1944, PubMed 24048243

Berenz EC, Amstadter AB, Aggen SH, Knudsen GP, Reichborn-Kjennerud T, Gardner CO, Kendler KS (2013)
Childhood trauma and personality disorder criterion counts: a co-twin control analysis
J Abnorm Psychol, 122 (4), 1070-6
DOI 10.1037/a0034238, PubMed 24364608

Gjerde LC, Knudsen GP, Czajkowski N, Gillespie N, Aggen SH, Røysamb E, Reichborn-Kjennerud T, Tambs K, Kendler KS, Orstavik RE (2013)
Genetic and environmental contributions to long-term sick leave and disability pension: a population-based study of young adult Norwegian twins
Twin Res Hum Genet, 16 (4), 759-66
DOI 10.1017/thg.2013.36, PubMed 23743022

Høiseth G, Magnus P, Knudsen GP, Jansen MD, Næss O, Tambs K, Mørland J (2013)
Is ADH1C genotype relevant for the cardioprotective effect of alcohol?
Alcohol, 47 (2), 81-4
DOI 10.1016/j.alcohol.2012.12.005, PubMed 23321361

Graff-Iversen S, Jansen MD, Hoff DA, Høiseth G, Knudsen GP, Magnus P, Mørland J, Normann PT, Næss OE, Tambs K (2012)
Divergent associations of drinking frequency and binge consumption of alcohol with mortality within the same cohort
J Epidemiol Community Health, 67 (4), 350-7
DOI 10.1136/jech-2012-201564, PubMed 23235547

Nilsen TS, Knudsen GP, Gervin K, Brandt I, Røysamb E, Tambs K, Orstavik R, Lyle R, Reichborn-Kjennerud T, Magnus P, Harris JR (2012)
The Norwegian Twin Registry from a public health perspective: a research update
Twin Res Hum Genet, 16 (1), 285-95
DOI 10.1017/thg.2012.117, PubMed 23186607

Amstadter AB, Aggen SH, Knudsen GP, Reichborn-Kjennerud T, Kendler KS (2012)
Potentially traumatic event exposure, posttraumatic stress disorder, and Axis I and II comorbidity in a population-based study of Norwegian young adults
Soc Psychiatry Psychiatr Epidemiol, 48 (2), 215-23
DOI 10.1007/s00127-012-0537-2, PubMed 22782308

Amstadter AB, Aggen SH, Knudsen GP, Reichborn-Kjennerud T, Kendler KS (2012)
A population-based study of familial and individual-specific environmental contributions to traumatic event exposure and posttraumatic stress disorder symptoms in a Norwegian twin sample
Twin Res Hum Genet, 15 (5), 656-62
DOI 10.1017/thg.2012.43, PubMed 22877512

Gjerde LC, Czajkowski N, Røysamb E, Orstavik RE, Knudsen GP, Ostby K, Torgersen S, Myers J, Kendler KS, Reichborn-Kjennerud T (2012)
The heritability of avoidant and dependent personality disorder assessed by personal interview and questionnaire
Acta Psychiatr Scand, 126 (6), 448-57
DOI 10.1111/j.1600-0447.2012.01862.x, PubMed 22486635

Magnus P, Bakke E, Hoff DA, Høiseth G, Graff-Iversen S, Knudsen GP, Myhre R, Normann PT, Næss Ø, Tambs K, Thelle DS, Mørland J (2011)
Controlling for high-density lipoprotein cholesterol does not affect the magnitude of the relationship between alcohol and coronary heart disease
Circulation, 124 (21), 2296-302
DOI 10.1161/CIRCULATIONAHA.111.036491, PubMed 22042888

Kendler KS, Aggen SH, Knudsen GP, Røysamb E, Neale MC, Reichborn-Kjennerud T (2010)
The structure of genetic and environmental risk factors for syndromal and subsyndromal common DSM-IV axis I and all axis II disorders
Am J Psychiatry, 168 (1), 29-39
DOI 10.1176/appi.ajp.2010.10030340, PubMed 20952461

Knudsen GP (2009)
Gender bias in autoimmune diseases: X chromosome inactivation in women with multiple sclerosis
J Neurol Sci, 286 (1-2), 43-6
DOI 10.1016/j.jns.2009.04.022, PubMed 19411081

Brix TH, Hansen PS, Knudsen GP, Kringen MK, Kyvik KO, Orstavik KH, Hegedüs L (2009)
No link between X chromosome inactivation pattern and simple goiter in females: evidence from a twin study
Thyroid, 19 (2), 165-9
DOI 10.1089/thy.2008.0380, PubMed 19191747

Knudsen GP, Harbo HF, Smestad C, Celius EG, Akesson E, Oturai A, Ryder LP, Spurkland A, Ørstavik KH (2007)
X chromosome inactivation in females with multiple sclerosis
Eur J Neurol, 14 (12), 1392-6
DOI 10.1111/j.1468-1331.2007.01987.x, PubMed 17970735

Ørstavik KH, Knudsen GP, Nordgarden H, Ormerod E, Strømme P, Lazarou LP, Rosser LG, Prescott T, Houge G (2007)
Severe hypohidrotic ectodermal dysplasia in a girl caused by a de novo 9;X insertion that includes XIST and disrupts the EDA gene
Am J Med Genet A, 143A (13), 1510-3
DOI 10.1002/ajmg.a.31797, PubMed 17568423

Knudsen GP, Pedersen J, Klingenberg O, Lygren I, Ørstavik KH (2007)
Increased skewing of X chromosome inactivation with age in both blood and buccal cells
Cytogenet Genome Res, 116 (1-2), 24-8
DOI 10.1159/000097414, PubMed 17268174

Knudsen GP, Neilson TC, Pedersen J, Kerr A, Schwartz M, Hulten M, Bailey ME, Orstavik KH (2006)
Increased skewing of X chromosome inactivation in Rett syndrome patients and their mothers
Eur J Hum Genet, 14 (11), 1189-94
DOI 10.1038/sj.ejhg.5201682, PubMed 16823396

Ørstavik KH, Kristiansen M, Knudsen GP, Storhaug K, Vege A, Eiklid K, Abrahamsen TG, Smahi A, Steen-Johnsen J (2006)
Novel splicing mutation in the NEMO (IKK-gamma) gene with severe immunodeficiency and heterogeneity of X-chromosome inactivation
Am J Med Genet A, 140 (1), 31-9
DOI 10.1002/ajmg.a.31026, PubMed 16333836

Charman T, Neilson TC, Mash V, Archer H, Gardiner MT, Knudsen GP, McDonnell A, Perry J, Whatley SD, Bunyan DJ, Ravn K, Mount RH, Hastings RP, Hulten M, Orstavik KH, Reilly S, Cass H, Clarke A, Kerr AM, Bailey ME (2005)
Dimensional phenotypic analysis and functional categorisation of mutations reveal novel genotype-phenotype associations in Rett syndrome
Eur J Hum Genet, 13 (10), 1121-30
DOI 10.1038/sj.ejhg.5201471, PubMed 16077736

Brix TH, Knudsen GP, Kristiansen M, Kyvik KO, Orstavik KH, Hegedüs L (2005)
High frequency of skewed X-chromosome inactivation in females with autoimmune thyroid disease: a possible explanation for the female predisposition to thyroid autoimmunity
J Clin Endocrinol Metab, 90 (11), 5949-53
DOI 10.1210/jc.2005-1366, PubMed 16105963

Grogan PM, Tanner SM, Ørstavik KH, Knudsen GP, Saperstein DS, Vogel H, Barohn RJ, Herbelin LL, McVey AL, Katz JS (2005)
Myopathy with skeletal asymmetry and hemidiaphragm elevation is caused by myotubularin mutations
Neurology, 64 (9), 1638-40
DOI 10.1212/01.WNL.0000160393.99621.D0, PubMed 15883335

Kristiansen M, Knudsen GP, Maguire P, Margolin S, Pedersen J, Lindblom A, Ørstavik KH (2005)
High incidence of skewed X chromosome inactivation in young patients with familial non-BRCA1/BRCA2 breast cancer
J Med Genet, 42 (11), 877-80
DOI 10.1136/jmg.2005.032433, PubMed 15879497

Kristiansen M, Knudsen GP, Bathum L, Naumova AK, Sørensen TI, Brix TH, Svendsen AJ, Christensen K, Kyvik KO, Ørstavik KH (2005)
Twin study of genetic and aging effects on X chromosome inactivation
Eur J Hum Genet, 13 (5), 599-606
DOI 10.1038/sj.ejhg.5201398, PubMed 15756296

Fritz B, Kunz J, Knudsen GP, Louwen F, Kennerknecht I, Eiben B, Orstavik KH, Friedrich U, Rehder H (2005)
Situs ambiguus in a female fetus with balanced (X;21) translocation--evidence for functional nullisomy of the ZIC3 gene?
Eur J Hum Genet, 13 (1), 34-40
DOI 10.1038/sj.ejhg.5201213, PubMed 15470371

Kristiansen M, Knudsen GP, Tanner SM, McEntagart M, Jungbluth H, Muntoni F, Sewry C, Gallati S, Ørstavik KH, Wallgren-Pettersson C (2003)
X-inactivation patterns in carriers of X-linked myotubular myopathy
Neuromuscul Disord, 13 (6), 468-71
DOI 10.1016/s0960-8966(03)00067-1, PubMed 12899873

Kristiansen M, Knudsen GP, Søyland A, Westvik J, Ørstavik KH (2002)
Phenotypic variation in Melnick-Needles syndrome is not reflected in X inactivation patterns from blood or buccal smear
Am J Med Genet, 108 (2), 120-7
DOI 10.1002/ajmg.10245, PubMed 11857561

Kristiansen M, Langerød A, Knudsen GP, Weber BL, Børresen-Dale AL, Orstavik KH (2002)
High frequency of skewed X inactivation in young breast cancer patients
J Med Genet, 39 (1), 30-3
DOI 10.1136/jmg.39.1.30, PubMed 11826021

Review articles

Bakken IJ, Ariansen AMS, Knudsen GP, Johansen KI, Vollset SE (2019)
The Norwegian Patient Registry and the Norwegian Registry for Primary Health Care: Research potential of two nationwide health-care registries
Scand J Public Health, 48 (1), 49-55
DOI 10.1177/1403494819859737, PubMed 31288711

Drover SSM, Villanger GD, Aase H, Skogheim TS, Longnecker MP, Zoeller RT, Reichborn-Kjennerud T, Knudsen GP, Zeiner P, Engel SM (2019)
Maternal Thyroid Function During Pregnancy or Neonatal Thyroid Function and Attention Deficit Hyperactivity Disorder: A Systematic Review
Epidemiology, 30 (1), 130-144
DOI 10.1097/EDE.0000000000000937, PubMed 30299402

Walhovd KB, Fjell AM, Westerhausen R, Nyberg L, Ebmeier KP, Lindenberger U, Bartrés-Faz D, Baaré WFC, Siebner HR, Henson R, Drevon CA, Knudsen GP, Budin-Ljøsne I, Penninx BWJH, Ghisletta P, Rogeberg O, Tyler L, Bertram L, for Lifebrain Consortium (2017)
Healthy minds from 0-100 years: Optimising the use of European brain imaging cohorts ("Lifebrain")
Eur Psychiatry, 47, 76-87
DOI 10.1016/j.eurpsy.2017.10.005, PubMed 29127911

Ludvigsson JF, Håberg SE, Knudsen GP, Lafolie P, Zoega H, Sarkkola C, von Kraemer S, Weiderpass E, Nørgaard M (2015)
Ethical aspects of registry-based research in the Nordic countries
Clin Epidemiol, 7, 491-508
DOI 10.2147/CLEP.S90589, PubMed 26648756

Nielsen CS, Knudsen GP, Steingrímsdóttir ÓA (2012)
Twin studies of pain
Clin Genet, 82 (4), 331-40
DOI 10.1111/j.1399-0004.2012.01938.x, PubMed 22823509