Kjetil Nordbø Jørgensen

• Jørgensen, Kjetil Nordbø; Nerland, Stener; Slapø, Nora Berz; Norbom, Linn Bonaventure; Mørch-Johnsen, Lynn Egeland & Wortinger, Laura Anne [Show all 13 contributors for this article] (2024). Assessing regional intracortical myelination in schizophrenia spectrum and bipolar disorders using the optimized T1w/T2w-ratio. Psychological Medicine. ISSN 0033-2917. doi: 10.1017/S0033291724000503.
• Andreou, Dimitrios; Steen, Nils Eiel; Mørch-Johnsen, Lynn Egeland; Jørgensen, Kjetil Nordbø; Wortinger, Laura Anne & Barth, Claudia [Show all 19 contributors for this article] (2024). Toxoplasma gondii infection associated with inflammasome activation and neuronal injury. Scientific Reports. ISSN 2045-2322. 14(1). doi: 10.1038/s41598-024-55887-9.
• Shafi, Dur E. Shahnaz; Jørgensen, Kjetil Nordbø; Bjella, Thomas; Nesvåg, Ragnar; Dieset, Ingrid & Melle, Ingrid [Show all 8 contributors for this article] (2024). Prescriptions of psychotropic and somatic medications among patients with severe mental disorders and healthy controls in a naturalistic study. Nordic Journal of Psychiatry. ISSN 0803-9488. doi: 10.1080/08039488.2024.2305806. Show summary

  Purpose Psychotropic and somatic medications are both used in treating severe mental disorders (SMDs). Realistic estimates of the prevalence of use across medication categories are needed. We obtained this in a clinical cohort of patients with SMD and healthy controls (HCs). Materials and methods Prescriptions filled at Norwegian pharmacies the year before and after admittance to the Thematically Organized Psychosis (TOP) study were examined in 1406 patients with SMD (mean age 32.5 years, 48.2% women) and 920 HC (34.1 years, 46.2% women). Using data from the Norwegian Prescription Database (NorPD), the number of users in different anatomical therapeutic chemical (ATC) categories was compared using logistic regression. Population estimates were used as reference data. Results Use of antipsychotics (N05A), antiepileptics (N03A), antidepressants (N06A), anxiolytics (N05B), hypnotics and sedatives (N05C), anticholinergics (N04A), psychostimulants, attention deficit hyperactivity disorder and nootropic agents (N06B) and drugs for addiction disorders (N07B) was significantly more prevalent in patients with SMD than HC. Use of diabetes treatment (A10), antithrombotic drugs (B01), beta blockers (C07), lipid modifiers (C10), and thyroid and endocrine therapeutics (H03) was also more prevalent in patients with SMD, but with two exceptions somatic medication use was comparable to the general population. Among HC, there was low prevalence of use for most medication categories. Conclusion Patients were using psychiatric medications, but also several types of somatic medications, more often than HC. Still, somatic medication use was mostly not higher than in the general population. The results indicate that HC had low use of most medication types.

• Bakke, Laura Anne Wortinger; Stavrum, Anne-Kristin Støbakk; Shadrin, Alexey; Szabo, Attila; Rukke, Sondre Høeg & Nerland, Stener [Show all 17 contributors for this article] (2024). Divergent epigenetic responses to perinatal asphyxia in severe mental disorders. Translational Psychiatry. ISSN 2158-3188. 14(1). doi: 10.1038/s41398-023-02709-7.
• Ruggeri, Aurora; Nerland, Stener; Mørch-Johnsen, Lynn Egeland; Jørgensen, Kjetil Nordbø; Barth, Claudia & Bakke, Laura Anne Wortinger [Show all 9 contributors for this article] (2024). Hypothalamic Subunit Volumes in Schizophrenia and Bipolar Spectrum Disorders. Schizophrenia Bulletin. ISSN 0586-7614. doi: 10.1093/schbul/sbad176.
• Wortinger, Laura Anne ; Shadrin, Alexey; Szabo, Attila; Nerland, Stener; Smelror, Runar & Jørgensen, Kjetil Nordbø [Show all 13 contributors for this article] (2023). The impact of placental genomic risk for schizophrenia and birth asphyxia on brain development. Translational Psychiatry. ISSN 2158-3188. 13(1). doi: 10.1038/s41398-023-02639-4. Full text in Research Archive Show summary

  The placenta plays a role in fetal brain development, and pregnancy and birth complications can be signs of placental dysfunction. Birth asphyxia is associated with smaller head size and higher risk of developing schizophrenia (SZ), but whether birth asphyxia and placental genomic risk factors associated with SZ are related and how they might impact brain development is unclear. 433 adult patients with SZ and 870 healthy controls were clinically evaluated and underwent brain magnetic resonance imaging. Pregnancy and birth information were obtained from the Medical Birth Registry of Norway. Polygenic risk scores (PRS) from the latest genomewide association study in SZ were differentiated into placental PRS (PlacPRS) and non-placental PRS. If the interaction between PRSs and birth asphyxia on case-control status was significant, neonatal head circumference (nHC) and adult intracranial volume (ICV) were further evaluated with these variables using multiple regression. PlacPRS in individuals with a history of birth asphyxia was associated with a higher likelihood of being a patient with SZ (t = 2.10, p = 0.018). We found a significant interaction between PlacPRS and birth asphyxia on nHC in the whole sample (t = −2.43, p = 0.008), with higher placental PRS for SZ associated with lower nHC in those with birth asphyxia. This relationship was specific to males (t = −2.71, p = 0.005) and also found with their adult ICV (t = −1.97, p = 0.028). These findings suggest that placental pathophysiology and birth asphyxia may affect early and late trajectories of brain development, particularly in males with a higher vulnerability to SZ. This knowledge might lead to new strategies of treatment and prevention in SZ.

• Barth, Claudia; Nerland, Stener; Jørgensen, Kjetil Nordbø; Haatveit, Beathe; Bakke, Laura Anne Wortinger & Melle, Ingrid [Show all 10 contributors for this article] (2023). Altered Sex Differences in Hippocampal Subfield Volumes in Schizophrenia. Schizophrenia Bulletin. ISSN 0586-7614. 50(1), p. 107–119. doi: 10.1093/schbul/sbad091. Full text in Research Archive Show summary

  Background and hypothesis: The hippocampus is a heterogenous brain structure that differs between the sexes and has been implicated in the pathophysiology of psychiatric illnesses. Here, we explored sex and diagnostic group differences in hippocampal subfield volumes, in individuals with schizophrenia spectrum disorder (SZ), bipolar disorders (BD), and healthy controls (CTL). Study design: One thousand and five hundred and twenty-one participants underwent T1-weighted magnetic resonance imaging (SZ, n = 452, mean age 30.7 ± 9.2 [SD] years, males 59.1%; BD, n = 316, 33.7 ± 11.4, 41.5%; CTL, n = 753, 34.1 ± 9.1, 55.6%). Total hippocampal, subfield, and intracranial volumes were estimated with Freesurfer (v6.0.0). Analysis of covariance and multiple regression models were fitted to examine sex-by-diagnostic (sub)group interactions in volume. In SZ and BD, separately, associations between volumes and clinical as well as cognitive measures were examined between the sexes using regression models. Study results: Significant sex-by-group interactions were found for the total hippocampus, dentate gyrus, molecular layer, presubiculum, fimbria, hippocampal-amygdaloid transition area, and CA4, indicating a larger volumetric deficit in male patients relative to female patients when compared with same-sex CTL. Subgroup analyses revealed that this interaction was driven by males with schizophrenia. Effect sizes were overall small (partial η < 0.02). We found no significant sex differences in the associations between hippocampal volumes and clinical or cognitive measures in SZ and BD. Conclusions: Using a well-powered sample, our findings indicate that the pattern of morphological sex differences in hippocampal subfields is altered in individuals with schizophrenia relative to CTL, due to higher volumetric deficits in males.

• Slapø, Nora Berz; Nerland, Stener; Jørgensen, Kjetil Nordbø; Mørch-Johnsen, Lynn Egeland; Pettersen, Johanne Hagen & Roelfs, Daniel [Show all 22 contributors for this article] (2023). Auditory Cortex Thickness Is Associated With N100 Amplitude in Schizophrenia Spectrum Disorders. Schizophrenia Bulletin Open. ISSN 2632-7899. 4(1). doi: 10.1093/schizbullopen/sgad015. Full text in Research Archive
• Birkenæs, Viktoria; Bakken, Nora Refsum; Frei, Evgeniia; Jaholkowski, Piotr Pawel; Smeland, Olav Bjerkehagen & Woldeyohannes, Markos Tesfaye [Show all 15 contributors for this article] (2023). Psychometric Properties and Diagnostic Associations of the Short-Form Community Assessment of Psychic Experiences in a Population-Based Sample of 29 021 Adult Men. Schizophrenia Bulletin. ISSN 0586-7614. 49(5), p. 1229–1238. doi: 10.1093/schbul/sbad074. Full text in Research Archive
• Mørch-Johnsen, Lynn Egeland; Jørgensen, Kjetil Nordbø; Barth, Claudia; Nerland, Stener; Bringslid, Ida Kippersund & Wortinger, Laura Anne [Show all 10 contributors for this article] (2023). Thalamic nuclei volumes in schizophrenia and bipolar spectrum disorders – Associations with diagnosis and clinical characteristics. Schizophrenia Research. ISSN 0920-9964. 256, p. 26–35. doi: 10.1016/j.schres.2023.04.008. Full text in Research Archive Show summary

  Background The thalamus is central to brain functions ranging from primary sensory processing to higher-order cognition. Structural deficits in thalamic association nuclei such as the pulvinar and mediodorsal nuclei have previously been reported in schizophrenia. However, the specificity with regards to clinical presentation, and whether or not bipolar disorder (BD) is associated with similar alterations is unclear. Methods We investigated thalamic nuclei volumes in 334 patients with schizophrenia spectrum disorders (SSD) (median age 29 years, 59 % male), 322 patients with BD (30 years, 40 % male), and 826 healthy controls (HC) (34 years, 54 % male). Volumes of 25 thalamic nuclei were extracted from T1-weighted magnetic resonance imaging using an automated Bayesian segmentation method and compared between groups. Furthermore, we explored associations with clinical characteristics across diagnostic groups, including psychotic and mood symptoms and medication use, as well as diagnostic subtype in BD. Results Significantly smaller volumes were found in the mediodorsal, pulvinar, and lateral and medial geniculate thalamic nuclei in SSD. Similarly, smaller volumes were found in BD in the same four regions, but mediodorsal nucleus volume alterations were limited to its lateral part and pulvinar alterations to its anterior region. Smaller volumes in BD compared to HC were seen only in BD type I, not BD type II. Across diagnoses, having more negative symptoms was associated with smaller pulvinar volumes. Conclusions Structural alterations were found in both SSD and BD, mainly in the thalamic association nuclei. Structural deficits in the pulvinar may be of relevance for negative symptoms.

• Slapø, Nora Berz; Jørgensen, Kjetil Nordbø; Elvsåshagen, Torbjørn; Nerland, Stener; Roelfs, Daniel & Valstad, Mathias [Show all 18 contributors for this article] (2023). Relationship between function and structure in the visual cortex in healthy individuals and in patients with severe mental disorders. Psychiatry Research : Neuroimaging. ISSN 0925-4927. 332. doi: 10.1016/j.pscychresns.2023.111633. Full text in Research Archive Show summary

  Patients with schizophrenia spectrum disorders (SCZspect) and bipolar disorders (BD) show impaired function in the primary visual cortex (V1), indicated by altered visual evoked potential (VEP). While the neural substrate for altered VEP in these patients remains elusive, altered V1 structure may play a role. One previous study found a positive relationship between the amplitude of the P100 component of the VEP and V1 surface area, but not V1 thickness, in a small sample of healthy individuals. Here, we aimed to replicate these findings in a larger healthy control (HC) sample (n = 307) and to examine the same relationship in patients with SCZspect (n = 30) or BD (n = 45). We also compared the mean P100 amplitude, V1 surface area and V1 thickness between controls and patients and found no significant group differences. In HC only, we found a significant positive P100-V1 surface area association, while there were no significant P100-V1 thickness relationships in HC, SCZspect or BD. Together, our results confirm previous findings of a positive P100-V1 surface area association in HC, whereas larger patient samples are needed to further clarify the function-structure relationship in V1 in SCZspect and BD.

• Andreou, Dimitrios; Jørgensen, Kjetil Nordbø; Nerland, Stener; Yolken, Robert H.; Haukvik, Unn Kristin Hansen & Andreassen, Ole [Show all 7 contributors for this article] (2022). Cytomegalovirus Infection Associated with Smaller Total Cortical Surface Area in Schizophrenia Spectrum Disorders. Schizophrenia Bulletin. ISSN 0586-7614. 48(5), p. 1164–1173. doi: 10.1093/schbul/sbac036. Full text in Research Archive
• Andreou, Dimitrios; Jørgensen, Kjetil Nordbø; Nerland, Stener; Ueland, Torill; Vaskinn, Anja & Haukvik, Unn Kristin Hansen [Show all 9 contributors for this article] (2022). Herpes simplex virus 1 infection on grey matter and general intelligence in severe mental illness. Translational Psychiatry. ISSN 2158-3188. 12(1). doi: 10.1038/s41398-022-02044-3. Full text in Research Archive
• Nerland, Stener; Stokkan, Therese; Jørgensen, Kjetil Nordbø; Wortinger, Laura Anne ; Richard, Geneviève & Beck, Dani [Show all 11 contributors for this article] (2022). A comparison of intracranial volume estimation methods and their cross-sectional and longitudinal associations with age. Human Brain Mapping. ISSN 1065-9471. doi: 10.1002/hbm.25978. Full text in Research Archive Show summary

  Intracranial volume (ICV) is frequently used in volumetric magnetic resonance imaging (MRI) studies, both as a covariate and as a variable of interest. Findings of associations between ICV and age have varied, potentially due to differences in ICV estimation methods. Here, we compared five commonly used ICV estimation methods and their associations with age. T1-weighted cross-sectional MRI data was included for 651 healthy individuals recruited through the NORMENT Centre (mean age = 46.1 years, range = 12.0–85.8 years) and 2410 healthy individuals recruited through the UK Biobank study (UKB, mean age = 63.2 years, range = 47.0–80.3 years), where longitudinal data was also available. ICV was estimated with FreeSurfer (eTIV and sbTIV), SPM12, CAT12, and FSL. We found overall high correlations across ICV estimation method, with the lowest observed correlations between FSL and eTIV (r = .87) and between FSL and CAT12 (r = .89). Widespread proportional bias was found, indicating that the agreement between methods varied as a function of head size. Body weight, age, sex, and mean ICV across methods explained the most variance in the differences between ICV estimation methods, indicating possible confounding for some estimation methods. We found both positive and negative cross-sectional associations with age, depending on dataset and ICV estimation method. Longitudinal ICV reductions were found for all ICV estimation methods, with annual percentage change ranging from −0.293% to −0.416%. This convergence of longitudinal results across ICV estimation methods offers strong evidence for age-related ICV reductions in mid- to late adulthood.

• Wortinger, Laura Anne ; Barth, Claudia; Nerland, Stener; Jørgensen, Kjetil Nordbø; Shadrin, Alexey & Szabo, Attila [Show all 11 contributors for this article] (2021). Association of Birth Asphyxia With Regional White Matter Abnormalities Among Patients With Schizophrenia and Bipolar Disorders. JAMA Network Open. ISSN 2574-3805. 4(12). doi: 10.1001/jamanetworkopen.2021.39759. Full text in Research Archive Show summary

  Importance: White matter (WM) abnormalities are commonly reported in psychiatric disorders. Whether peripartum insufficiencies in brain oxygenation, known as birth asphyxia, are associated with WM of patients with severe mental disorders is unclear. Objective: To examine the association between birth asphyxia and WM in adult patients with schizophrenia and bipolar disorders (BDs) compared with healthy adults. Design, setting, and participants: In this case-control study, all individuals participating in the ongoing Thematically Organized Psychosis project were linked to the Medical Birth Registry of Norway (MBRN), where a subset of 271 patients (case group) and 529 healthy individuals (control group) had undergone diffusion-weighted imaging (DWI). Statistical analyses were performed from June 16, 2020, to March 9, 2021. Exposures: Birth asphyxia was defined based on measures from standardized reporting at birth in the MBRN. Main outcomes and measures: Associations between birth asphyxia and WM regions of interest diffusion metrics, ie, fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD), were compared between groups using analysis of covariance, adjusted for age, age squared, and sex. Results: Of the 850 adults included in the study, 271 were in the case group (140 [52%] female individuals; mean [SD] age, 28.64 [7.43] years) and 579 were in the control group (245 [42%] female individuals; mean [SD] age, 33.54 [8.31] years). Birth asphyxia measures were identified in 15% to 16% of participants, independent of group. The posterior limb of the internal capsule (PLIC) showed a significant diagnostic group × birth asphyxia interaction (F(1, 843) = 11.46; P = .001), reflecting a stronger association between birth asphyxia and FA in the case group than the control group. RD, but not AD, also displayed a significant diagnostic group × birth asphyxia interaction (F(1, 843) = 9.28; P = .002) in the PLIC, with higher values in patients with birth asphyxia and similar effect sizes as observed for FA. Conclusions and relevance: In this case-control study, abnormalities in the PLIC of adult patients with birth asphyxia may suggest a greater susceptibility to hypoxia in patients with severe mental illness, which could lead to myelin damage or impeded brain development. Echoing recent early-stage schizophrenia studies, abnormalities of the PLIC are relevant to psychiatric disorders, as the PLIC contains important WM brain pathways associated with language, cognitive function, and sensory function, which are impaired in schizophrenia and BDs.

• Nerland, Stener; Jørgensen, Kjetil Nordbø; Nordhøy, Wibeke; Maximov, Ivan; Bugge, Robin Antony Birkeland & Westlye, Lars Tjelta [Show all 9 contributors for this article] (2021). Multisite reproducibility and test-retest reliability of the T1w/T2w-ratio: A comparison of processing methods. NeuroImage. ISSN 1053-8119. 245. doi: 10.1016/j.neuroimage.2021.118709. Full text in Research Archive
• Hilland, Eva; Johannessen, Cecilie Haggag; Jonassen, Rune; Alnæs, Dag; Jørgensen, Kjetil Nordbø & Barth, Claudia [Show all 17 contributors for this article] (2021). Aberrant default mode connectivity in adolescents with early-onset psychosis: A resting state fMRI study. NeuroImage: Clinical. ISSN 2213-1582. 33. doi: 10.1016/j.nicl.2021.102881. Full text in Research Archive
• Andreou, Dimitrios; Steen, Nils Eiel; Jørgensen, Kjetil Nordbø; Smelror, Runar; Wedervang-Resell, Kirsten & Nerland, Stener [Show all 25 contributors for this article] (2021). Lower circulating neuron-specific enolase concentrations in adults and adolescents with severe mental illness. Psychological Medicine. ISSN 0033-2917. p. 1–10. doi: 10.1017/S0033291721003056. Full text in Research Archive
• Andreou, Dimitrios; Jørgensen, Kjetil Nordbø; Nerland, Stener; Smelror, Runar; Wedervang-Resell, Kirsten & Johannessen, Cecilie Haggag [Show all 11 contributors for this article] (2021). Lower plasma total tau in adolescent psychosis: Involvement of the orbitofrontal cortex. Journal of Psychiatric Research. ISSN 0022-3956. 144, p. 255–261. doi: 10.1016/j.jpsychires.2021.10.031. Full text in Research Archive
• Andreou, Dimitrios; Jørgensen, Kjetil Nordbø; Nerland, Stener; Engen, Kristine; Yolken, Robert H. & Andreassen, Ole [Show all 7 contributors for this article] (2021). Cytomegalovirus infection associated with smaller dentate gyrus in men with severe mental illness. Brain, Behavior, and Immunity. ISSN 0889-1591. 96, p. 54–62. doi: 10.1016/j.bbi.2021.05.009. Full text in Research Archive
• Smelror, Runar; Johannessen, Cecilie Haggag; Wedervang-Resell, Kirsten; Jørgensen, Kjetil Nordbø; Barth, Claudia & Andreou, Dimitrios [Show all 11 contributors for this article] (2021). Cognitive Impairment Profile in Adolescent Early-Onset Psychosis Usingthe MATRICS Battery: Age and Sex Effects. Neuropsychology. ISSN 0894-4105. 35(3), p. 300–309. doi: 10.1037/neu0000723.
• Andreou, Dimitrios; Jørgensen, Kjetil Nordbø; Bakke, Laura A Wortinger; Engen, Kristine; Vaskinn, Anja & Ueland, Torill [Show all 9 contributors for this article] (2021). Cytomegalovirus infection and IQ in patients with severe mental illness and healthy individuals. Psychiatry Research. ISSN 0165-1781. doi: 10.1016/j.psychres.2021.113929. Full text in Research Archive Show summary

  Cytomegalovirus (CMV) infection in immunocompetent adults is usually asymptomatic, but results in lifelong latency. Infection occurring congenitally or in immunodeficiency can lead to cognitive impairment. We aimed to investigate the associations between CMV exposure and intelligence quotient (IQ) in patients with schizophrenia spectrum disorders (SZS), bipolar spectrum disorders (BDS) and healthy controls (HC). CMV immunoglobulin G antibody concentrations were measured by immunoassay and expressed as dichotomous measures (seropositive/CMV+ vs. seronegative/CMV-). Based on a significant CMV-by-diagnosis-by-sex interaction on IQ, we investigated main and interaction effects of CMV and sex on IQ in each diagnostic category. Significant CMV-by-sex interactions were found in patient groups. In SZS, CMV+ female patients (n = 50) had significantly lower IQ than CMV- female patients (n = 33), whereas CMV+ (n = 48) and CMV- (n = 45) male patients did not differ in IQ. In BDS, CMV+ (n = 49) and CMV- (n = 37) female patients did not differ in IQ, whereas CMV+ male patients (n = 33) had significantly higher IQ than CMV- male patients (n = 32). Among HC, CMV+ (n = 138) and CMV- (n = 118) male participants as well as CMV+ (n = 125) and CMV- (n = 93) female participants did not differ in IQ. Our findings suggest that CMV exposure may affect IQ in patients with severe mental illness but not HC.

• Wortinger, Laura Anne; Jørgensen, Kjetil Nordbø; Barth, Claudia; Nerland, Stener; Smelror, Runar Elle & Vaskinn, Anja [Show all 9 contributors for this article] (2021). Significant association between intracranial volume and verbal intellectual abilities in patients with schizophrenia and a history of birth asphyxia. Psychological Medicine. ISSN 0033-2917. p. 1–10. doi: 10.1017/S0033291721000489. Full text in Research Archive
• Barth, Claudia; Nerland, Stener; de Lange, Ann-Marie Glasø; Wortinger, Laura Anne ; Hilland, Eva & Andreassen, Ole Andreas [Show all 8 contributors for this article] (2021). In Vivo Amygdala Nuclei Volumes in Schizophrenia and Bipolar Disorders. Schizophrenia Bulletin. ISSN 0586-7614. 47(5), p. 1431–1441. doi: 10.1093/schbul/sbaa192. Full text in Research Archive
• Bakke, Laura A Wortinger; Engen, Kristine; Barth, Claudia; Andreassen, Ole Andreas; Jørgensen, Kjetil Nordbø & Agartz, Ingrid (2020). Asphyxia at birth affects brain structure in patients on the schizophrenia-bipolar disorder spectrum and healthy participants. Psychological Medicine. ISSN 0033-2917. doi: 10.1017/S0033291720002779. Full text in Research Archive
• Haukvik, Unn Kristin H.; Gurholt, Tiril Pedersen; Nerland, Stener; Elvsåshagen, Torbjørn; Akudjedu, Theophilus N. & Alda, Martin [Show all 97 contributors for this article] (2020). In vivo hippocampal subfield volumes in bipolar disorder—A mega‐analysis from The Enhancing Neuro Imaging Genetics through Meta‐Analysis Bipolar Disorder Working Group. Human Brain Mapping. ISSN 1065-9471. 43, p. 385–398. doi: 10.1002/hbm.25249. Full text in Research Archive
• Engen, Kristine; Wortinger, Laura Anne ; Jørgensen, Kjetil Nordbø; Lundberg, Mathias; Bohman, Hannes & Smelror, Runar [Show all 10 contributors for this article] (2020). Autoantibodies to the N-methyl-D-aspartate receptor in adolescents with early onset psychosis and healthy controls. Frontiers in Psychiatry. ISSN 1664-0640. 11:666, p. 1–7. doi: 10.3389/fpsyt.2020.00666. Full text in Research Archive
• Gurholt, Tiril Pedersen; Lonning, Vera Louise Hiorth; Nerland, Stener; Jørgensen, Kjetil Nordbø; Haukvik, Unn Kristin H. & Alloza, Clara [Show all 41 contributors for this article] (2020). Intracranial and subcortical volumes in adolescents with early‐onset psychosis: A multisite mega‐analysis from the ENIGMA consortium. Human Brain Mapping. ISSN 1065-9471. p. 373–384. doi: 10.1002/hbm.25212. Full text in Research Archive
• Barth, Claudia; Jørgensen, Kjetil Nordbø; Wortinger, Laura Anne ; Nerland, Stener; Jönsson, Erik Gunnar & Agartz, Ingrid (2020). Trajectories of brain volume change over 13 years in chronic schizophrenia. Schizophrenia Research. ISSN 0920-9964. doi: 10.1016/j.schres.2020.05.014.
• Smelror, Runar; Rund, Bjørn Rishovd; Lonning, Vera Louise Hiorth; Jørgensen, Kjetil Nordbø; Wedervang-Resell, Kirsten & Andreassen, Ole Andreas [Show all 9 contributors for this article] (2020). Negative and disorganized symptoms mediate the relationship between verbal learning and global functioning in adolescents with early-onset psychosis. European Child and Adolescent Psychiatry. ISSN 1018-8827. doi: 10.1007/s00787-020-01479-7. Full text in Research Archive
• Berge, Torkil; Bull-Hansen, Bente; Solberg, Erik Ekker; Heyerdahl, Else Resser; Jørgensen, Kjetil Nordbø & Vinge, Leif Erik [Show all 9 contributors for this article] (2019). Screening for symptomer på depresjon og angst ved en hjertemedisinsk avdeling. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 139(14). doi: 10.4045/tidsskr.18.0570.
• Bakke, Laura A. Wortinger ; Engen, Kristine; Barth, Claudia; Lonning, Vera Louise Hiorth; Jørgensen, Kjetil Nordbø & Andreassen, Ole Andreas [Show all 10 contributors for this article] (2019). Obstetric complications and intelligence in patients on the schizophrenia-bipolar spectrum and healthy participants. Psychological Medicine. ISSN 0033-2917. p. 1–9. doi: 10.1017/S0033291719002046.
• Di Sero, Alessia; Jørgensen, Kjetil Nordbø; Nerland, Stener; Melle, Ingrid; Andreassen, Ole Andreas & Jovicich, Jorge [Show all 7 contributors for this article] (2019). Antipsychotic treatment and basal ganglia volumes: Exploring the role of receptor occupancy, dosage and remission status. Schizophrenia Research. ISSN 0920-9964. 208, p. 114–123. doi: 10.1016/j.schres.2019.04.002.
• Smelror, Runar; Jørgensen, Kjetil Nordbø; Lonning, Vera Louise Hiorth; Kelleher, Ian; Cannon, Mary & DeRosse, Pamela [Show all 16 contributors for this article] (2018). Healthy adolescent performance with standardized scoring tables for the MATRICS Consensus Cognitive Battery: A multisite study. Schizophrenia Bulletin. ISSN 0586-7614. 45(4), p. 773–783. doi: 10.1093/schbul/sby131.
• Gjerde, Priyanthi Borgen; Jørgensen, Kjetil Nordbø; Steen, Nils Eiel; Melle, Ingrid; Andreassen, Ole Andreas & Steen, Vidar Martin [Show all 7 contributors for this article] (2018). Association between olanzapine treatment and brain cortical thickness and gray/white matter contrast is moderated by cholesterol in psychotic disorders. Psychiatry Research : Neuroimaging. ISSN 0925-4927. 282, p. 55–63. doi: 10.1016/j.pscychresns.2018.10.001.
• Mørch-Johnsen, Lynn; Nerland, Stener; Jørgensen, Kjetil Nordbø; Osnes, Kåre; Hartberg, Cecilie Bhandari & Andreassen, Ole Andreas [Show all 9 contributors for this article] (2018). Cortical thickness abnormalities in bipolar disorder patients with a lifetime history of auditory hallucinations. Bipolar Disorders. ISSN 1398-5647. 20(7), p. 647–657. doi: 10.1111/bdi.12627.
• Berg, Akiah Ottesen; Jørgensen, Kjetil Nordbø; Nerhus, Mari; Athanasiu, Lavinia; Popejoy, Alice & Bettella, Francesco [Show all 13 contributors for this article] (2018). Vitamin D levels, brain volume, and genetic architecture in patients with psychosis. PLOS ONE. ISSN 1932-6203. 13(8). doi: 10.1371/journal.pone.0200250. Full text in Research Archive
• Gurholt, Tiril Pedersen; Osnes, Kåre; Nerhus, Mari; Jørgensen, Kjetil Nordbø; Lonning, Vera Louise Hiorth & Berg, Akiah Ottesen [Show all 9 contributors for this article] (2018). Vitamin D, Folate and the Intracranial Volume in Schizophrenia and Bipolar Disorder and Healthy Controls. Scientific Reports. ISSN 2045-2322. 8. doi: 10.1038/s41598-018-29141-y. Full text in Research Archive
• Van Erp, Theo G.M.; Walton, Esther; Hibar, Derrek; Schmaal, Lianne; Jiang, Wenhao & Glahn, David C. [Show all 151 contributors for this article] (2018). Cortical brain abnormalities in 4474 individuals with schizophrenia and 5098 control subjects via the Enhancing Neuro Imaging Genetics Through Meta Analysis (ENIGMA) Consortium. Biological Psychiatry. ISSN 0006-3223. doi: 10.1016/j.biopsych.2018.04.023. Full text in Research Archive
• Walton, E; Hibar, Derrek; Van Erp, Theo G M; Potkin, Steven G; Roiz-Santiañez, Roberto & Crespo-Facorro, B [Show all 58 contributors for this article] (2018). Prefrontal cortical thinning links to negative symptoms in schizophrenia via the ENIGMA consortium. Psychological Medicine. ISSN 0033-2917. 48(1), p. 82–94. doi: 10.1017/S0033291717001283. Full text in Research Archive
• Iversen, Trude Seselie Jahr; Steen, Nils Eiel; Dieset, Ingrid; Hope, Sigrun; Mørch, Ragni Helene & Gardsjord, Erlend Strand [Show all 11 contributors for this article] (2018). Side effect burden of antipsychotic drugs in real life - Impact of gender and polypharmacy. Progress in Neuro-psychopharmacology and Biological Psychiatry. ISSN 0278-5846. 82, p. 263–271. doi: 10.1016/j.pnpbp.2017.11.004.
• Doan, Nhat Trung; Kaufmann, Tobias; Bettella, Francesco; Jørgensen, Kjetil Nordbø; Brandt, Christine Lycke & Moberget, Torgeir [Show all 15 contributors for this article] (2017). Distinct multivariate brain morphological patterns and their added predictive value with cognitive and polygenic risk scores in mental disorders. NeuroImage: Clinical. ISSN 2213-1582. 15, p. 719–731. doi: 10.1016/j.nicl.2017.06.014. Full text in Research Archive
• Walton, Esther Fintan; Hibar, Derrek; Van Erp, Theo G.M.; Potkin, Steven G.; Roiz-Santiáñez, Roberto & Crespo-Facorro, Benedicto [Show all 59 contributors for this article] (2017). Positive symptoms associate with cortical thinning in the superior temporal gyrus via the ENIGMA Schizophrenia consortium. Acta Psychiatrica Scandinavica. ISSN 0001-690X. 135(5), p. 439–447. doi: 10.1111/acps.12718.
• Jørgensen, Kjetil Nordbø; Nesvåg, Ragnar; Nerland, Stener; Mørch-Johnsen, Lynn; Westlye, Lars Tjelta & Lange, Elisabeth [Show all 11 contributors for this article] (2017). Brain volume change in first-episode psychosis: an effect of antipsychotic medication independent of BMI change. Acta Psychiatrica Scandinavica. ISSN 0001-690X. 135(2), p. 117–126. doi: 10.1111/acps.12677.
• Lange, Elisabeth; Nerland, Stener; Jørgensen, Kjetil Nordbø; Mørch-Johnsen, Lynn; Nesvåg, Ragnar & Hartberg, Cecilie Bhandari [Show all 11 contributors for this article] (2017). Alcohol use is associated with thinner cerebral cortex and larger ventricles in schizophrenia, bipolar disorder and healthy controls. Psychological Medicine. ISSN 0033-2917. 47(4), p. 655–668. doi: 10.1017/S0033291716002920.
• Mørch-Johnsen, Lynn; Nesvåg, Ragnar; Jørgensen, Kjetil Nordbø; Lange, Elisabeth; Hartberg, Cecilie Bhandari & Haukvik, Unn Kristin H. [Show all 13 contributors for this article] (2016). Auditory cortex characteristics in schizophrenia: Associations with auditory hallucinations. Schizophrenia Bulletin. ISSN 0586-7614. 43(1), p. 75–83. doi: 10.1093/schbul/sbw130.
• Jørgensen, Kjetil Nordbø; Nerland, Stener; Norbom, Linn Christin Bonaventure; Doan, Nhat Trung; Nesvåg, Ragnar & Mørch-Johnsen, Lynn [Show all 11 contributors for this article] (2016). Increased MRI-based cortical grey/white-matter contrast in sensory and motor regions in schizophrenia and bipolar disorder. Psychological Medicine. ISSN 0033-2917. 46(9), p. 1971–1985. doi: 10.1017/S0033291716000593.
• Haukvik, Unn Kristin H.; Hartberg, Cecilie Bhandari; Nerland, Stener; Jørgensen, Kjetil Nordbø; Lange, Elisabeth & Simonsen, Carmen Elisabeth [Show all 11 contributors for this article] (2016). No progressive brain changes during a 1-year follow-up of patients with first-episode psychosis. Psychological Medicine. ISSN 0033-2917. 46(3), p. 589–598. doi: 10.1017/S003329171500210X. Show summary

  Background. First-episode psychosis (FEP) patients show structural brain abnormalities. Whether the changes are progressive or not remain under debate, and the results from longitudinal magnetic resonance imaging (MRI) studies are mixed. We investigated if FEP patients showed a different pattern of regional brain structural change over a 1-year period compared with healthy controls, and if putative changes correlated with clinical characteristics and outcome. Method. MRIs of 79 FEP patients [SCID-I-verified diagnoses: schizophrenia, psychotic bipolar disorder, or other psychoses, mean age 27.6 (S.D. = 7.7) years, 66% male] and 82 healthy controls [age 29.3 (S.D. = 7.2) years, 66% male] were acquired from the same 1.5 T scanner at baseline and 1-year follow-up as part of the Thematically Organized Psychosis (TOP) study, Oslo, Norway. Scans were automatically processed with the longitudinal stream in FreeSurfer that creates an unbiased within-subject template image. General linear models were used to analyse longitudinal change in a wide range of subcortical volumes and detailed thickness and surface area estimates across the entire cortex, and associations with clinical characteristics. Results. FEP patients and controls did not differ significantly in annual percentage change in cortical thickness or area in any cortical region, or in any of the subcortical structures after adjustment for multiple comparisons. Within the FEP group, duration of untreated psychosis, age at illness onset, antipsychotic medication use and remission at follow-up were not related to longitudinal brain change. Conclusions. We found no significant longitudinal brain changes over a 1-year period in FEP patients. Our results do not support early progressive brain changes in psychotic disorders.

• Jørgensen, Kjetil Nordbø; Nesvåg, Ragnar; Gunleiksrud, Sindre; Raballo, Andrea; Jönsson, Erik Gunnar & Agartz, Ingrid (2015). First- and second-generation antipsychotic drug treatment and subcortical brain morphology in schizophrenia. European Archives of Psychiatry and Clinical Neuroscience. ISSN 0940-1334. doi: 10.1007/s00406-015-0650-9.
• Jørgensen, Kjetil Nordbø; Skjærvø, Ingeborg; Mørch-Johnsen, Lynn; Haukvik, Unn Kristin H.; Lange, Elisabeth & Melle, Ingrid [Show all 8 contributors for this article] (2015). Cigarette smoking is associated with thinner cingulate and insular cortices in patients with severe mental illness. Journal of Psychiatry & Neuroscience. ISSN 1180-4882. 40(4), p. 241–249. doi: 10.1503/jpn.140163.
• Hartberg, Cecilie Bhandari; Jørgensen, Kjetil Nordbø; Haukvik, Unn Kristin H.; Westlye, Lars Tjelta; Melle, Ingrid & Andreassen, Ole Andreas [Show all 7 contributors for this article] (2015). Lithium treatment and hippocampal subfields and amygdala volumes in bipolar disorder. Bipolar Disorders. ISSN 1398-5647. 17(5), p. 496–506. doi: 10.1111/bdi.12295.
• Mørch-Johnsen, Lynn; Nesvåg, Ragnar; Færden, Ann; Haukvik, Unn Kristin H.; Jørgensen, Kjetil Nordbø & Lange, Elisabeth [Show all 9 contributors for this article] (2015). Brain structure abnormalities in first-episode psychosis patients with persistent apathy. Schizophrenia Research. ISSN 0920-9964. 164(1-3), p. 59–64. doi: 10.1016/j.schres.2015.03.001. Full text in Research Archive
• Haukvik, Unn Kristin H.; Westlye, Lars Tjelta; Mørch-Johnsen, Lynn; Jørgensen, Kjetil Nordbø; Lange, Elisabeth & Dale, Anders M. [Show all 9 contributors for this article] (2015). In Vivo Hippocampal Subfield Volumes in Schizophrenia and Bipolar Disorder. Biological Psychiatry. ISSN 0006-3223. 77(6), p. 581–588. doi: 10.1016/j.biopsych.2014.06.020.
• Jørgensen, Kjetil Nordbø; Rømma, V. & Rundmo, Torbjørn (2009). Associations between ward atmosphere, patient satisfaction and outcome. Journal of Psychiatric and Mental Health Nursing. ISSN 1351-0126. 16(2), p. 113–120. doi: 10.1111/j.1365-2850.2008.01333.x. Show summary

  Previous studies have found important associations between the ward atmosphere and patient satisfaction. However, fewer studies have examined the relationship between ward atmosphere and outcome of treatment. The aim of the study was to examine whether or not differences in ward atmosphere were associated with differences in satisfaction and outcome. Eighty patients at three different ward units responded to a questionnaire at admission and by the time of discharge from the hospital. The questionnaire comprised the ward atmosphere scale, a five-item index of patient satisfaction, the Generalized Self-Efficacy Scale, an index of life satisfaction and the symptom checklist SCL-90R. The results showed that differences in the treatment environment between the ward units were associated with differences in patient satisfaction. There was mixed evidence for associations between ward atmosphere and outcome, while no associations were found between ward atmosphere and self-efficacy and life satisfaction. The results may suggest that the relationship between ward atmosphere and outcomes of treatment may be of a more indirect character than the relationship between ward atmosphere and satisfaction.

View all works in Cristin

• Jørgensen, Kjetil Nordbø (2019). En rett og en vrang? - om vrangforestillinger ved psykose. Psykologisk tidsskrift. ISSN 1501-7508. 23(2), p. 22–29.
• Jørgensen, Kjetil Nordbø; Nerland, Stener; Moberget, Torgeir; Elvsåshagen, Torbjørn; Jönsson, Erik Gunnar & Andreassen, Ole Andreas [Show all 7 contributors for this article] (2019). Optimizing the T1/T2 ratio for analysis within and between subjects.
• Nerland, Stener; Antosz, Anna; Lonning, Vera Louise Hiorth; Jørgensen, Kjetil Nordbø; Mørch-Johnsen, Lynn Egeland & Andreassen, Ole Andreas [Show all 7 contributors for this article] (2017). A Manual for Classifying Anatomical Variation of Heschl's Gyrus.
• Gurholt, Tiril Pedersen; Nerhus, Mari; Osnes, Kåre; Jørgensen, Kjetil Nordbø; Berg, Akiah Ottesen & Andreassen, Ole Andreas [Show all 8 contributors for this article] (2017). Age-Related Effect of Vitamin D on Hippocampus Volume in Schizophrenia and Bipolar Disorder.
• Nerland, Stener; Jørgensen, Kjetil Nordbø; Jahren, Bjørn; Melle, Ingrid; Andreassen, Ole Andreas & Agartz, Ingrid (2016). A Topological Characterisation of Cortical Folding in Schizophrenia and Bipolar Disorder.
• Jørgensen, Kjetil Nordbø; Nerland, Stener; Norbom, Linn Christin Bonaventure; Doan, Nhat Trung; Nesvåg, Ragnar & Haukvik, Unn Kristin H. [Show all 10 contributors for this article] (2015). Increased cortical gray/white matter intensity contrast in schizophrenia and bipolar disorder compared to healthy controls.
• Mørch-Johnsen, Lynn; Nesvåg, Ragnar; Færden, Ann; Haukvik, Unn Kristin H.; Jørgensen, Kjetil Nordbø & Lange, Elisabeth [Show all 9 contributors for this article] (2014). Brain structure changes in first-episode psychosis patients with persistent apathy. Schizophrenia Research. ISSN 0920-9964. 153, p. S210–S210. doi: 10.1016/S0920-9964(14)70608-5.
• Mørch-Johnsen, Lynn; Nesvåg, Ragnar; Færden, Ann; Haukvik, Unn Kristin H.; Jørgensen, Kjetil Nordbø & Lange, Elisabeth [Show all 9 contributors for this article] (2014). Brain structure changes in first-episode psychosis patients with persistent apathy.
• Jørgensen, Kjetil Nordbø; Skjærvø, Ingeborg; Mørch-Johnsen, Lynn; Haukvik, Unn Kristin H.; Lange, Elisabeth & Melle, Ingrid [Show all 8 contributors for this article] (2014). Poster #T107 Cigarette smoking is associated with reduced cingulate and insular thickness among patients with psychosis and bipolar spectrum disorders. Schizophrenia Research. ISSN 0920-9964. 153(1). doi: 10.1016/S0920-9964(14)70924-7.
• Torvik, Fartein Ask; Jørgensen, Kjetil Nordbø & Gjerde, Line Cecilie (2014). Psykose og genetikk. Tidsskrift for Norsk Psykologforening. ISSN 0332-6470. 51(4), p. 328–328.
• Torvik, Fartein Ask; Jørgensen, Kjetil Nordbø & Gjerde, Line Cecilie (2014). Fortsatt uholdbart om tvillingstudier. Tidsskrift for Norsk Psykologforening. ISSN 0332-6470. 51(2), p. 158–159.
• Torvik, Fartein Ask; Jørgensen, Kjetil Nordbø & Gjerde, Line Cecilie (2013). Uholdbart om tvillingstudier. Tidsskrift for Norsk Psykologforening. ISSN 0332-6470. 50(12), p. 1212–1214.
• Gjerde, Ingrid Johanne & Jørgensen, Kjetil N (2011). Ungdoms opplevelse av hva som gjør det lettere å ta kontakt for psykiske vansker - en kvalitativ fokusgruppeundersøkelse. Psykologi i kommunen (PIK). ISSN 1892-3364. 5, p. 33–44.
• Jørgensen, Kjetil Nordbø & Malt, Ulrik Fredrik (2011). Metacognition in mood and anxiety disorders: a literature review. Bipolar Disorders. ISSN 1398-5647. 13, p. 58–59.
• Jørgensen, Kjetil Nordbø; Rømma, V. & Rundmo, Torbjørn (2008). Differences in perceptions of the ward atmosphere among patients and staff in psychiatric inpatient care. International Journal of Psychology (IJP). ISSN 0020-7594. 43.
• Jørgensen, K. N.; Rømma, V. & Rundmo, Torbjørn (2008). Differences in Perceptions of the Ward Atmosphere among Patients and Staff in Psychiatric Inpatient Care.
• Rømma, V.; Jørgensen, K. N. & Rundmo, Torbjørn (2007). Headline Differences of Optimal Environments for Psychotic versus Non-psychotic Patients in Psychiatric In-patient Care.
• Jørgensen, Kjetil Nordbø; Rømma, V. & Rundmo, Torbjørn (2007). Associations between Ward Atmosphere, Symptom Reduction, Self-efficacy and Life Satisfaction in Psychiatric In-Pateint Care.
• Jørgensen, Kjetil Nordbø & Nilsen, Wendy (2006). Flyt som ressurs - intervju med Lisa Vivoll Straume. Psykologisk tidsskrift. ISSN 1501-7508.

View all works in Cristin