• Attention-deficit hyperactivity disorder shares copy number variant risk with schizophrenia and autism spectrum disorder 

      Gudmundsson, Ólafur Ó.; Walters, Gudmundur Bragi; Ingason, Andrés; Johansson, Stefan; Zayats, Tetyana; Athanasiu, Lavinia; Sønderby, Ida Elken; Gustafsson, Omar; Nawaz, Muhammad Sulaman; Jónsson, Gudbjörn F.; Jónsson, Lina; Knappskog, Per; Ingvarsdóttir, Ester; Davidsdóttir, Katrin; Djurovic, Srdjan; Knudsen, Gun Peggy Strømstad; Askeland, Ragna Bugge; Haraldsdóttir, Gyda S.; Baldursson, Gísli; Magnússon, Páll; Sigurdsson, Engilbert; Gudbjartsson, Daníel Fannar; Stéfansson, Hreinn; Andreassen, Ole Andreas; Haavik, Jan; Reichborn-Kjennerud, Ted; Stefánsson, Kári (Peer reviewed; Journal article, 2019-10-17)
      Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable common childhood-onset neurodevelopmental disorder. Some rare copy number variations (CNVs) affect multiple neurodevelopmental disorders such as ...
    • A candidate gene investigation of methylphenidate response in adult attention-deficit/hyperactivity disorder patients: results from a naturalistic study 

      Hegvik, Tor-Arne; Jacobsen, Kaya Kvarme; Fredriksen, Mats; Zayats, Tetyana; Haavik, Jan (Peer reviewed; Journal article, 2016-08)
      Attention-deficit/hyperactivity disorder (ADHD) is a common childhood onset neuropsychiatric disorder with a complex and heterogeneous symptomatology. Persistence of ADHD symptoms into adulthood is common. Methylphenidate ...
    • Druggable genome in attention deficit/hyperactivity disorder and its co-morbid conditions. New avenues for treatment. 

      Hegvik, Tor-Arne; Waløen, Kai; Pandey, Sunil Kumar; Faraone, Stephen V.; Haavik, Jan; Zayats, Tetyana (Peer reviewed; Journal article, 2019)
      Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder with only symptomatic care available. Genome-wide association (GWA) studies can provide a starting point in the search for novel drug ...
    • Epistatic and gene wide effects in YWHA and aromatic amino hydroxylase genes across ADHD and other common neuropsychiatric disorders: Association with YWHAE 

      Jacobsen, Kaya Kvarme; Kleppe, Rune; Johansson, Stefan; Zayats, Tetyana; Haavik, Jan (Peer reviewed; Journal article, 2015-09)
      Monoamines critically modulate neurophysiological functions affected in several neuropsychiatric disorders. We therefore examined genes encoding key enzymes of catecholamine and serotonin biosynthesis (tyrosine and tryptophan ...
    • Exome chip analyses in adult attention deficit hyperactivity disorder 

      Zayats, Tetyana; Jacobsen, Kaya Kvarme; Kleppe, Rune; Jacob, CP; Kittel-Schneider, Sarah; Ribases, Marta; Ramos-Quiroga, JA; Richarte, Vanesa; Casas, M; Mota, NR; Grevet, EH; Klein, M; Corominas, J; Bralten, Janita; Galesloot, T; Vasquez, AA; Herms, S; Forstner, AJ; Larsson, H; Breen, G; Asherson, P; Gross-Lesch, Silke; Lesch, KP; Cichon, Sven; Gabrielsen, Maiken Elvestad; Holmen, Oddgeir Lingaas; Bau, CH; Buitelaar, Jan; Kiemeney, L; Faraone, Stephen V.; Cormand, B; Franke, Barbara; Reif, Andreas; Haavik, Jan; Johansson, Stefan (Peer reviewed; Journal article, 2016)
      Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable childhood-onset neuropsychiatric condition, often persisting into adulthood. The genetic architecture of ADHD, particularly in adults, is largely unknown. ...
    • Expanding the toolbox of ADHD genetics. How can we make sense of parent of origin effects in ADHD and related behavioral phenotypes? 

      Zayats, Tetyana; Johansson, Stefan; Haavik, Jan (Peer reviewed; Journal article, 2015-10-16)
      Genome-wide association (GWA) studies have shown that many different genetic variants cumulatively contribute to the risk of psychiatric disorders. It has also been demonstrated that various parent-of-origin effects (POE) ...
    • Genome wide association study identifies variants in NBEA associated with migraine in bipolar disorder 

      Jacobsen, Kaya Kvarme; Nievergelt, Caroline M.; Zayats, Tetyana; Greenwood, Tifany A.; Anttila, Verneri; Akiskal, Hagop Souren; Haavik, Jan; Fasmer, Ole Bernt; Kelsoe, John R.; Johansson, Stefan; Ødegaard, Ketil Joachim (Peer reviewed; Journal article, 2015-10-12)
      Background. Migraine is a common comorbidity among individuals with bipolar disorder, but the underlying mechanisms for this co-occurrence are poorly understood. The aim of this study was to investigate the genetic background ...
    • Genome-wide analyses of aggressiveness in attention-deficit hyperactivity disorder 

      Brevik, Erlend Joramo; van Donkelaar, Marjolein M J; Weber, Heike; Sanchez-Mora, Cristina; Jacob, Christian; Rivero, Olga; Kittel-Schneider, Sarah; Garcia-Martinez, Iris; Aebi, Marcel; van Hulzen, Kimm; Cormand, Bru; Ramos-Quiroga, Josep A; Lesch, Klaus-Peter; Reif, Andreas; Ribases, Marta; Franke, Barbara; Posserud, Maj-Britt Rocio; Johansson, Stefan; Lundervold, Astri; Haavik, Jan; Zayats, Tetyana (Peer reviewed; Journal article, 2016-03-29)
      Aggressiveness is a behavioral trait that has the potential to be harmful to individuals and society. With an estimated heritability of about 40%, genetics is important in its development. We performed an exploratory ...
    • Genome-wide analysis of attention deficit hyperactivity disorder in Norway 

      Zayats, Tetyana; Athanasiu, Lavinia; Sønderby, Ida Elken; Djurovic, Srdjan; Westlye, Lars Tjelta; Tamnes, Christian Krog; Fladby, Tormod; Aase, Heidi; Zeiner, Pål; Reichborn-Kjennerud, Ted; Knappskog, Per; Knudsen, Gun Peggy; Andreassen, Ole Andreas; Johansson, Stefan; Haavik, Jan (Peer reviewed; Journal article, 2015-04-13)
      Background Attention deficit hyperactivity disorder (ADHD) is a highly heritable neuropsychiatric condition, but it has been difficult to identify genes underlying this disorder. This study aimed to explore genetics of ...
    • Implication of NOTCH1 Gene in Susceptibility to Anxiety and Depression among Sexual Abuse Victims 

      Steine, Iris Mulders; Zayats, Tetyana; Stansberg, Christine; Pallesen, Ståle; Mrdalj, Jelena; Håvik, Bjarte; Soule, Jonathan; Haavik, Jan; Milde, Anne Marita; Skrede, Silje; Murison, Robert; Krystal, John H; Grønli, Janne (Peer reviewed; Journal article, 2016-12-13)
      Sexual abuse contributes to the development of multiple forms of psychopathology, including anxiety and depression, but the extent to which genetics contributes to these disorders among sexual abuse victims remains unclear. ...
    • Implication of the APP gene in intellectual abilities 

      Myrum, Craig; Nikolaienko, Oleksii; Bramham, Clive R.; Haavik, Jan; Zayats, Tetyana (Peer reviewed; Journal article, 2017)
      Background: Cognitive functions are highly heritable and polygenic, though the source of this genetic influence is unclear. On the neurobiological level, these functions rely on effective neuroplasticity, in which the ...
    • Novel loci associated with attention-deficit/hyperactivity disorder are revealed by leveraging polygenic overlap with educational attainment 

      Shadrin, Alexey A.; Smeland, Olav Bjerkehagen; Zayats, Tetyana; Schork, Andrew J; Frei, Oleksandr; Bettella, Francesco; Witoelar, Aree; Li, Wen; Eriksen, Jon Alm; Krull, Florian; Djurovic, Srdjan; Faraone, Stephen V.; Reichborn-Kjennerud, Ted; Thompson, Wesley K; Johansson, Stefan; Haavik, Jan; Dale, Anders; Wang, Yunpeng; Andreassen, Ole Andreas (Peer reviewed; Journal article, 2018-02)
      Objective Attention-deficit/hyperactivity disorder (ADHD) is a common and highly heritable psychiatric condition. By exploiting the reported relationship between ADHD and educational attainment (EA), we aimed to improve ...
    • Patterns of psychiatric comorbidity and genetic correlations provide new insights into differences between attention-deficit/hyperactivity disorder and autism spectrum disorder 

      Solberg, Berit Skretting; Zayats, Tetyana; Posserud, Maj-Britt Rocio; Halmøy, Anne; Engeland, Anders; Haavik, Jan; Klungsøyr, Kari (Peer reviewed; Journal article, 2019-04-28)
      Background Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) share common genetic factors but seem to have specific patterns of psychiatric comorbidities. There are few systematic studies ...