• 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 ...
    • The effect of electroconvulsive therapy (ECT) on serum tryptophan metabolites 

      Aarsland, Tore Ivar Malmei; Leskauskaite, Ieva; Midttun, Øivind; Ulvik, Arve; Ueland, Per Magne; Oltedal, Leif; Erchinger, Vera Jane; Ødegaard, Ketil Joachim; Haavik, Jan; Kessler, Ute (Peer reviewed; Journal article, 2019-05-31)
      Background: Prior studies suggest that activation of the tryptophan catabolism via the kynurenine pathway by proinflammatory cytokines may be involved in the pathophysiology of depression. Electroconvulsive therapy (ECT) ...
    • Effects of ECT in treatment of depression: Study protocol for a prospective neuroradiological study of acute and longitudinal effects on brain structure and function 

      Oltedal, Leif; Kessler, Ute; Ersland, Lars; Grüner, Renate; Andreassen, Ole Andreas; Haavik, Jan; Hoff, Per Ivar; Hammar, Åsa; Dale, Anders Martin; Hugdahl, Kenneth; Ødegaard, Ketil Joachim (Peer reviewed; Journal article, 2015-05-01)
      Background Major depression can be a serious and debilitating condition. For some patients in a treatment resistant depressive episode, electroconvulsive treatment (ECT) is the only treatment that is effective. Although ...
    • 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 ...
    • Event-related-potential (ERP) correlates of performance monitoring in adults with attention-deficit hyperactivity disorder (ADHD) 

      Marquardt, Lynn Anne; Eichele, Heike; Lundervold, Astri; Haavik, Jan; Eichele, Tom (Peer reviewed; Journal article, 2018-04-11)
      Introduction: Attention-deficit hyperactivity disorder (ADHD) is one of the most frequent neurodevelopmental disorders in children and tends to persist into adulthood. Evidence from neuropsychological, neuroimaging, and ...
    • 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) ...
    • Functional studies of tyrosine hydroxylase missense variants reveal distinct patterns of molecular defects in dopa-responsive dystonia 

      Fossbakk, Agnete; Kleppe, Rune; Knappskog, Per; Martinez, Aurora; Haavik, Jan (Peer reviewed; Journal article, 2014-06-03)
      Congenital tyrosine hydroxylase deficiency (THD) is found in autosomal-recessive Dopa-responsive dystonia and related neurological syndromes. The clinical manifestations of THD are variable, ranging from early-onset lethal ...
    • GADL1 is a multifunctional decarboxylase with tissue-specific roles in β-alanine and carnosine production 

      Mahootchi, Elaheh; Homaei, Selina Cannon; Kleppe, Rune; Winge, Ingeborg; Hegvik, Tor-Arne; Perez, Roberto Megias; Totland, Christian; Mogavero, Floriana; Baumann, Anne; Glennon, Jeffrey Colm; Miletic, Hrvoje; Kursula, Petri; Haavik, Jan (Journal article; Peer reviewed, 2020)
      Carnosine and related β-alanine–containing peptides are believed to be important antioxidants, pH buffers, and neuromodulators. However, their biosynthetic routes and therapeutic potential are still being debated. This ...
    • Gender Differences in Psychiatric Comorbidity: Population-based study of 40,000 Adults with Attention-Deficit Hyperactivity Disorder 

      Solberg, Berit Skretting; Halmøy, Anne; Engeland, Anders; Igland, Jannicke; Haavik, Jan; Klungsøyr, Kari (Peer reviewed; Journal article, 2017-12-21)
      OBJECTIVE: We aimed at determining whether gender modified associations between ADHD and psychiatric comorbidities in adults. METHOD: We identified adults with ADHD by linking Norwegian national registries and compared ...
    • 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 ...
    • Identification of Genetic Loci Shared Between Attention-Deficit/Hyperactivity Disorder, Intelligence, and Educational Attainment 

      O`Connell, Kevin; Shadrin, Alexey A.; Smeland, Olav Bjerkehagen; Bahrami, Shahram; Frei, Oleksandr; Bettella, Francesco; Krull, Florian; Fan, Chun C.; Askeland, Ragna Bugge; Knudsen, Gun Peggy Strømstad; Halmøy, Anne; Steen, Nils Eiel; Ueland, Torill; Walters, Bragi; Davíðsdóttir, Katrín; Haraldsdóttir, Gyda S.; Guðmundsson, Ólafur; Stefansson, Hreinn; Reichborn-Kjennerud, Ted; Haavik, Jan; Dale, Anders M.; Stefánsson, Kári; Djurovic, Srdjan; Andreassen, Ole Andreas (Peer reviewed; Journal article, 2020)
      Background: Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that is consistently associated with lower levels of educational attainment. A recent large genome-wide association study identified ...
    • 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 ...
    • Individual Variability in Reaction Time and Prediction of Clinical Response to Methylphenidate in Adult ADHD: A Prospective Open Label Study Using Conners’ Continuous Performance Test II 

      Fredriksen, Mats; Egeland, Jens; Haavik, Jan; Fasmer, Ole Bernt (Peer reviewed; Journal article, 2019)
      Objective: The aim of this study was to examine whether reaction time parameters in adult patients with ADHD could predict their response to methylphenidate (MPH). Method: Previously unmedicated patients (N = 123) were ...
    • Insomnia, Alcohol Consumption and ADHD Symptoms in Adults 

      Lundervold, Astri J.; Jensen, Daniel André; Haavik, Jan (Journal article; Peer reviewed, 2020)
      Introduction Substance use disorders and insomnia are common in the general population, and particularly among adults with attention-deficit/hyperactivity disorder (ADHD). Here we investigated the relationship between ...
    • Mammalian CSAD and GADL1 have distinct biochemical properties and patterns of brain expression 

      Winge, Ingeborg; Teigen, Knut; Fossbakk, Agnete; Mahootchi, Elaheh; Kleppe, Rune; Sköldberg, Filip; Kämpe, Olle; Haavik, Jan (Peer reviewed; Journal article, 2015-11)
      Variants in the gene encoding the enzyme glutamic acid decarboxylase like 1 (GADL1) have been associated with response to lithium therapy. Both GADL1 and the related enzyme cysteine sulfinic acid decarboxylase (CSAD) have ...
    • Modelling cellular signal communication mediated by phosphorylation dependent interaction with 14-3-3 proteins 

      Kleppe, Rune; Ghorbani, Sadaf; Martinez, Aurora; Haavik, Jan (Peer reviewed; Journal article, 2014-01-03)
      The 14-3-3 proteins are important effectors of Ser/Thr phosphorylation in eukaryotic cells. Using mathematical modelling we investigated the roles of these proteins as effectors in signalling pathways that involve ...