Sommer, Prof. Iris
Iris Sommer is a Professor of Psychiatry at the University Medical Center in Groningen. Sommer trained as a physician and psychiatrist, completed a PhD with honours in the field of language in psychosis, and founded the Voice Clinic at UMC Utrecht. In 2016, her research on hallucinations – entitled ‘Do I See Ghosts?’ – was designated the Public Research Project of the Year. Her work in the field of language has continued, and she is now leading a European consortium investigating the appropriateness of automatic speech analysis as a biomarker for psychiatric disorders. As mental healthcare becomes increasingly digitized, voice-controlled AI is becoming widely used, and these new speech markers could aid in digital triage or medical decision-making.
The topics of Sommer’s groundbreaking work include the female brain, which has been studied far less than the male brain. With her team, she studies the role of female hormones (such as oestrogens) in mental health. These hormones play a major protective role in psychotic disorders. Recent work has indicated that women metabolize certain medications differently from men – with oestrogen once again playing a major role – and that menopause also affects the metabolization of some medications.
New exhibition Brainstorm in the University Museum
Hebben vrouwen een ander brein dan mannen? Dr Iris Sommer bij de Universiteit van Nederland
Dr Iris Sommer over haar boek 'Haperende Hersenen'
'Waarom hoor of zie je soms iets wat er helemaal niet is', Dr Sommer bij de Universiteit van Nederland
Iris Sommer bij The School of Life, Lowlands
Current psychiatric treatments are often based on clinical studies in which women are underrepresented. As a result, care for women is less evidence-based than it is for men. This has major consequences. For example, diagnoses in women are made later and, in some cases, missed entirely. Treatments are also less effective, thereby putting women at greater risk of overdose and, consequently, side effects. Moreover, menopause is not taken into account. With her team, Sommer is working hard to improve psychiatric treatment for female patients.
Sommer has written several books, including Haperende Hersenen (The Faltering Brain), Het Vrouwenbrein (The Female Brain), and De Bacterie en het Brein (The Bacteria and the Brain). In 2026, De stem van het Brein (The Voice of the Brain) will be published, exploring how we are shaped by language. In collaboration with BNR Nieuwsradio, Sommer has recorded five podcasts covering various topics related to the brain.
In 2022, she won the Huibregtsen Prize for Science and Society.
Previously in the news
Dr Iris Sommer at the University of the Netherlands:
Contact and further information
Publications
2026
Bosch,
E. L., de Beer, F., Cath, D. C.,
Gangadin, S. S., Touw, D. J., &
Sommer, I. E. C. (2026). Citalopram serum
concentrations in men and women of pre- and post-menopausal
age. Expert Opinion on Drug Metabolism &
Toxicology. Advance online publication. https://doi.org/10.1080/17425255.2026.2682178
Hosseini
Bondarabadi, M., Xu, M., Slingerland,
S., de Leeuw, J., Sommer, I., Harmsen, H.
J. M., van Laar, T., & van
Ijzendoorn, S. C. D. (2026). Generation and
characterization of induced pluripotent stem cell lines from one
Parkinson's disease patient carrying the GBA1 T369M variant and two
variant-free controls. Stem Cell
Research, 93, 103983. Advance online
publication. https://doi.org/10.1016/j.scr.2026.103983
Agorastos,
A., Thompson, T., Solmi, M., Cortese, S., Estradé, A., Radua,
J., Dragioti, E., Vancampfort, D., Thygesen, L. C., Aschauer, H.,
Schlögelhofer, M., Aschauer, E., Schneeberger, A., Huber, C.
G., Hasler, G., Conus, P., Do Cuénod, K. Q., von Känel,
R., Arrondo, G., ... Correll, C. U. (2026). Mental health,
coping and related risk factors during the first 2 years of the
COVID-19 pandemic in children: Nationally representative,
multi-wave, cross-sectional results from 12 countries from the
global COH-FIT study. European
Neuropsychopharmacology, 104, Article 112741.
https://doi.org/10.1016/j.euroneuro.2025.112741
Oomen,
P. P., Gangadin, S. S., de Haan, L., de Beer,
F., Beune, O. E., Oostendorp, D. A. D., Begemann, M.
J. H., Boonstra, N., Kikkert,
M., Koops, S., Veling, W.,
& Sommer, I. E. C. (2026). Negative association
between cognitive functioning and antipsychotic D2
receptor occupancy, affinity, and dose after first episode
psychosis. Psychological Medicine,
56. https://doi.org/10.1017/S0033291725102900
Zijp,
T. R., Nolte, S., Knobbe, T.
J., de Meijer, V. E., Gan, C.
T., Bakker, S. J. L., Sommer, I.
E., de Vries, S. T., & Touw, D.
J. (2026). Sex differences and impact of age-based
menopausal status on tacrolimus pharmacokinetics: results of the
TransplantLines biobank and cohort study. Expert
Opinion on Drug Metabolism & Toxicology. Advance
online publication. https://doi.org/10.1080/17425255.2026.2671063
PHAMOUS
investigators (2026). The Impact of Sex and Age on
Antipsychotic Serum Concentrations. Schizophrenia
Bulletin, 52(2). https://doi.org/10.1093/schbul/sbaf217
2025
Clozapine
Delphi Expert Panel, Siskind, D., Northwood, K., Pillinger, T.,
Chan, S., Correll, C. U., Cotes, R., Every-Palmer, S., Hahn, M.,
Howes, O., Kane, J. M., Kelly, D., Korman, N., Lappin, J., Mena,
C., Myles, N., & McCutcheon, R. A. (2026). Absolute
neutrophil count and adverse drug reaction monitoring during
clozapine treatment: consensus guidelines from a global Delphi
panel. The Lancet Psychiatry,
13(1), 77 - 86. https://doi.org/10.1016/S2215-0366(25)00098-7
HAMLETT
OPHELIA Consortium, Sommer, I. E., de Beer,
F., Gangadin, S., de Haan, L., Veling,
W., van Beveren, N., Boonstra, N.,
Rosema, B.-S., van Os, J., Kikkert, M.,
Koops, S., Noorman, J., Thielen, F., Wijnen,
B., & Begemann, M. (2026). Early Dose
Reduction or Discontinuation vs Maintenance Antipsychotics After
First Psychotic Episode Remission: A Randomized Clinical
Trial. Jama psychiatry,
83(1), 68-73. https://doi.org/10.1001/jamapsychiatry.2025.2525
de
Beer, F., Hamers, I. M. H., Prycka, M.,
Schoretsanitis, G., Gangadin, S. S., Touw, D.
J., & Sommer, I. E. C. (2026).
Trajectories of Clozapine Concentrations in Women Across
Menopausal Age. Schizophrenia
Bulletin, 52(2), Article sbaf186. https://doi.org/10.1093/schbul/sbaf186
Witt,
K., Kidwell, M., Doorduin, J., de Vries, E. F.
J., Sommer, I. E., Day, D. J., Ellenbroek, B.
A., & Guerrin, C. G. J. (2025). Apomorphine
susceptibility and prenatal infection alter neurodevelopment,
synaptic density and anticipatory behavior in rats.
Progress in Neuro-Psychopharmacology & Biological
Psychiatry, 142, Article 111490. https://doi.org/10.1016/j.pnpbp.2025.111490
Palominos,
C., Kirdun, M., Nikzad, A. H., Spilka, M. J., Homan, P.,
Sommer, I. E., Tang, S. X., & Hinzen, W.
(2025). A single composite index of semantic behavior tracks
symptoms of psychosis over time. Schizophrenia
Research, 279, 116-127. https://doi.org/10.1016/j.schres.2025.03.038
HAMLETT
OPHELIA Consortium, Kamphuis, S., Arias-Magnasco, A.,
Gangadin, S., Begemann, M., Wijnen,
B., Veling, W., de Haan, L., Sommer,
I., van Os, J., Bakker, P. R., &
Gülöksüz, S. (2025). Association between the
exposome score for schizophrenia and functioning in remitted
first-episode psychosis: results from the HAMLETT study.
Schizophrenia Research, 285,
223-231. https://doi.org/10.1016/j.schres.2025.09.023
Ioannou,
M., Borkent, J., Severance, E. G., Yolken, R.
H., Fasano, A., Sommer, I. E. C., & Haarman,
B. C. M. (2025). Biomarkers of intestinal permeability
in major psychiatric disorders: Distinct biological roles call for
a more nuanced application. Progress in
Neuro-Psychopharmacology and Biological Psychiatry,
139, Article 111405. https://doi.org/10.1016/j.pnpbp.2025.111405
Sommer,
I. E. C., van Tol, M. .-J., & de
Beer, F. (2025). Brainstorm: The Human Brain &
Research in Groningen. Exhibition, University of Groningen.
https://www.rug.nl/museum/exhibitions/2025/brainstorm-the-human-brain-and-research
d'Angremont,
E., Renken, R., van der Zee,
S., de Vries, E. F. J., van Laar,
T., & Sommer, I. E. C. (2025).
Cholinergic Denervation Patterns in Parkinson's Disease
Associated With Cognitive Impairment Across Domains.
Human brain mapping, 46(2), Article
e70047. https://doi.org/10.1002/hbm.70047
Solmi,
M., Thompson, T., Cortese, S., Estradé, A., Agorastos, A.,
Radua, J., Dragioti, E., Vancampfort, D., Thygesen, L. C.,
Aschauer, H., Schlögelhofer, M., Aschauer, E., Schneeberger,
A., Huber, C. G., Hasler, G., Conus, P., Cuénod, K. Q. D., von
Känel, R., Arrondo, G., ... Sommer, I. (2025).
Collaborative outcomes study on health and functioning during
infection times (COH-FIT): Insights on modifiable and
non-modifiable risk and protective factors for wellbeing and mental
health during the COVID-19 pandemic from multivariable and network
analyses. European
Neuropsychopharmacology, 90, 1-15. https://doi.org/10.1016/j.euroneuro.2024.07.010
Solmi,
M., Thompson, T., Cortese, S., Estradé, A., Agorastos, A.,
Radua, J., Dragioti, E., Vancampfort, D., Thygesen, L. C.,
Aschauer, H., Schlögelhofer, M., Aschauer, E., Schneeberger,
A. A., Huber, C. G., Hasler, G., Conus, P., Do Cuénod, K. Q.,
von Känel, R., Arrondo, G., ... Correll, C. U. (2025).
Collaborative Outcomes Study on Health and Functioning During
Infection Times (COH-FIT): Global and Risk-Group Stratified Course
of Well-Being and Mental Health During the COVID-19 Pandemic in
Adolescents. Journal of the American Academy of
Child and Adolescent Psychiatry, 64(4),
499-519. https://doi.org/10.1016/j.jaac.2024.07.932
Ciampelli,
S., de Boer, J., Koops, S.,
Voppel, A., Corona Hernandez, H.,
Oldehinkel, A., & Sommer, I. (2025).
Cross-sectional and longitudinal associations between anxiety
and acoustic-prosodic markers in adolescents.
Psychological Medicine, 55, Article
e322. https://doi.org/10.1017/S0033291725102274
de
Beer, F., de Vries, E., Wijnen,
B., Begemann, M. J. H., van Beveren, N., Boonstra,
N., Gangadin, S. S., de Haan, L., Hamers,
I. M. H., Veling, W., Koops,
S., & Sommer, I. E. C. (2025).
Dopamine D2/3R availability after discontinuation of
antipsychotic treatment: a [11C]raclopride PET study in remitted
first-episode psychosis patients. Psychological
Medicine, 55, Article e264. https://doi.org/10.1017/S003329172510161X
Sommer,
I. E. C., Brand, B. A., Zijp, T.
R., Mourits, M. J. E., & Touw, D.
J. (2025). Do women need a change in dose of
prescription drugs with onset of menopause? Time to find
out. BMC Medicine, 23(1),
Article 411. https://doi.org/10.1186/s12916-025-04253-1
Brand,
B. A., Boer, A. J., de Boer, J.
N., Bozaoglu, K., Morris, K., Rossell, S., &
Sommer, I. E. C. (2025). Genetic variants in COMT and
ESR1 genes shape treatment response to raloxifene in
schizophrenia-spectrum disorders.
Psychoneuroendocrinology, 172,
Article 107274. https://doi.org/10.1016/j.psyneuen.2024.107274
the
Lancet Psychiatry Physical Health Commission Consortium, Halstead,
S., Yap, C. X., Warren, N., Agarwal, S. M., Brand, B.
A., Chan, S. K. W., Cipriani, A., Correll, C. U., Crossley,
N., D'Ambrosio, E., Emsley, R., Firth, J., Gaughran, F., Gee, S.,
Hahn, M., Hayes, J. F., Heald, A., Howes, O. D., ... Pillinger, T.
(2025). Holistic prevention and management of physical health
side-effects of psychotropic medication: second report of the
Lancet Psychiatry Physical Health Commission. The
Lancet Psychiatry, 12(9), 673-699. https://doi.org/10.1016/S2215-0366(25)00162-2
The
INTEGRATE Advisory Group, McCutcheon, R. A., Pillinger, T.,
Varvari, I., Halstead, S., Ayinde, O. O., Crossley, N. A., Correll,
C. U., Hahn, M., Howes, O. D., Kane, J. M., Kabir, T.,
Konradsson-Geuken, Å., Lennox, B., Hui, C. L. M., Rossell, S.
L., Solmi, M., Sommer, I. E., Taipale, H., ... Warren,
N. (2025). INTEGRATE: international guidelines for the
algorithmic treatment of schizophrenia. The Lancet
Psychiatry, 12(5), 384-394. https://doi.org/10.1016/S2215-0366(25)00031-8
Sommer,
I. E. C., & van der Schot, B. (2025). Ophouden met
die schaamlipcorrecties. Ad Valvas. https://advalvas.vu.nl/student-maatschappij/ophouden-met-die-schaamlipcorrecties/
Hoprekstad,
G. E., Johnsen, E., Bartz-Johannessen, C., Bjarke, J. K., Drosos,
P., Fasmer, O. B., Gjerde, K. V., Reitan, S. K., Skrede, S.,
Sommer, I. E. C., Stabell, L., Steen, V. M., & Kroken,
R. A. (2025). Prednisolone add-on in early phase
schizophrenia: A randomized, double-blind, placebo-controlled pilot
study. Brain, Behavior, and Immunity -
Health, 48, Article 101047. https://doi.org/10.1016/j.bbih.2025.101047
Djordjevic,
M., Gangadin, S. S., de Haan, L.,
Jongsma, H. E., Oomen, P. P., Simons, C. J. P., Marcelis,
M., Nijland, M., Begemann, M. J. H., Sommer, I.
E. C., Kikkert, M. J., & Veling,
W. (2025). Psychological side effects of antipsychotic
medication after remission from first-episode psychosis: a HAMLETT
ecological momentary assessment study.
Psychological Medicine, 55, Article
e325. https://doi.org/10.1017/S003329172510216X
De
Jager, J. E., van der Weijden-Germann, M., van
Dellen, E., de Vries, E. F. J., Sommer, I. E.
C., & Nuninga, J. O. (2025).
Relationship between synaptic density and cortical
(micro)structure in healthy subjects, patients with schizophrenia
spectrum disorder and unaffected siblings: a multimodal [11C]UCB-J
PET and MRI study. Biological psychiatry.
Cognitive neuroscience and neuroimaging. Advance online
publication. https://doi.org/10.1016/j.bpsc.2025.11.008
HAMLETT
OPHELIA Consortium, Gangadin, S. S., de Beer,
F., Wijnen, B., Begemann, M., van
Beveren, N., Boonstra, N., de Haan, L., Kikkert,
M., Koops, S., van Os, J., Veling,
W., Wiersma, S., & Sommer, I. E. C. (2025).
Risk of relapse during tapering of antipsychotic medication
after a first psychotic episode: association with D2 receptor
affinity but not with tapering speed. World
psychiatry, 24(2), 240-249. https://doi.org/10.1002/wps.21315
Sommer,
I. E., Koops, S., & van den Heuvel, M.
(2025). rTMS treatment for refractory hallucinations: new
insights from classic targets. The Lancet
Psychiatry, 12(9), 621-623. https://doi.org/10.1016/S2215-0366(25)00218-4
Alsema,
A. M., Puvogel, S., Kracht, L.,
Webster, M. J., Weickert, C. S., Eggen, B. J.
L., & Sommer, I. E. C. (2025).
Schizophrenia-associated changes in neuronal subpopulations
in the human midbrain. Brain,
148(4), 1374-1388. https://doi.org/10.1093/brain/awae321
Ciampelli,
S., de Boer, J. N., Voppel, A.
E., Corona-Hernández, H., Koops,
S., Mota, N. B., & Sommer, I. E. C. (2025).
Syntactic network analysis in first-episode psychosis: toward
generalizability. Schizophrenia,
11(1), Article 147. https://doi.org/10.1038/s41537-025-00693-z
HAMLETT
and OPHELIA Consortium, Liu, Y., Sommer, I. E.,
Begemann, M. J. H., Gangadin, S. S., Perry, B.
I., Scheurink, T. A. W., van Beveren, N. J. M.,
Bakker, P. R., & Koops, S. (2025).
The Effects of Antipsychotic Dose Reduction on Movement
Disorders and Cardiometabolic Indices in Patients Remitted from a
First Episode of Psychosis. Schizophrenia
Bulletin, Article sbaf116. Advance online publication.
https://doi.org/10.1093/schbul/sbaf116
Bosch,
E. L., Sommer, I. E. C., & Touw, D.
J. (2025). The influence of female sex and estrogens
on drug pharmacokinetics: what is the evidence?
Expert Opinion on Drug Metabolism &
Toxicology, 21(6), 637-647. https://doi.org/10.1080/17425255.2025.2481891
Verdoux,
H., Bittner, R. A., Hasan, A., Qubad, M., Wagner, E., Lepetit, A.,
Arrojo-Romero, M., Bachmann, C., Beex-Oosterhuis, M., Bogers, J.,
Celofiga, A., Cohen, D., De Berardis, D., De Hert, M., De Las
Cuevas, C., Ebdrup, B. H., Fountoulakis, K. N., Guinart, D.,
Keating, D., ... Schulte, P. (2025). The time has come for
revising the rules of clozapine blood monitoring in Europe: A joint
expert statement from the European Clozapine Task Force.
European Psychiatry, 68(1), Article
e17. https://doi.org/10.1192/j.eurpsy.2024.1816
Leucht,
S., Yurtseven, D. S., Priller, J., Davis, J. M., van Os, J.,
& Sommer, I. E. C. (2025). Towards a name change
of schizophrenia: Positive and Negative Symptoms Disorder
(PND). European Archives of Psychiatry and
Clinical Neuroscience, 275(4), 963-971. https://doi.org/10.1007/s00406-025-02018-8
2024
EANM
Neuroimaging Committee, Rogeau, A., Boer, A. J.,
Guedj, E., Sala, A., Sommer, I. E., Veronese, M.,
& van der Weijden-Germann, M. (2025). EANM perspective on
clinical PET and SPECT imaging in schizophrenia-spectrum disorders:
a systematic review of longitudinal studies.
European Journal of Nuclear Medicine and Molecular
Imaging, 52, 876–899. https://doi.org/10.1007/s00259-024-06987-1
Borkent,
J., Ioannou, M., Neijzen,
D., Haarman, B. C. M., & Sommer, I.
E. C. (2025). Probiotic Formulation for Patients With
Bipolar or Schizophrenia Spectrum Disorder: A Double-Blind,
Randomized Placebo-Controlled Trial. Schizophrenia
Bulletin, 51(6), 1568-1580. Article sbae188.
https://doi.org/10.1093/schbul/sbae188
van
Opstal, D. P. J., Kia, S. M., Jakob, L., Somers, M., Sommer,
I. E. C., Winter-van Rossum, I., Kahn, R. S., Cahn, W.,
& Schnack, H. G. (2025). Psychosis Prognosis Predictor: A
continuous and uncertainty-aware prediction of treatment outcome in
first-episode psychosis. Acta Psychiatrica
Scandinavica, 151(3), 280-292. https://doi.org/10.1111/acps.13754
Smith,
K. A., Boyce, N., Chevance, A., Chiocchia, V., Correll, C. U.,
Donoghue, K., Ghodke, N., Kambeu, T., Malhi, G. S., Macleod, M.,
Milligan, L., Morgan, J., Potts, J., Robinson, E. S. J., Siafis,
S., Sommer, I. E. C., Voelkl, B., Salanti, G.,
Cipriani, A., & Higgins, J. P. T. (2025). Triangulating
evidence from the GALENOS living systematic review on trace
amine-associated receptor 1 (TAAR1) agonists in psychosis.
British Journal of Psychiatry, 226,
162-170. https://doi.org/10.1192/bjp.2024.237
TAPER
international research consortium, Koops, S., Allott,
K., De Haan, L., Chen, E., Hui, C., Killackey, E., Long, M.,
Moncrieff, J., Sommer, I., Stürup, A. E.,
Wunderink, L., & Begemann, M. (2024).
Addressing the Evidence to Practice Gap: What to Expect from
International Antipsychotic Dose Reduction Studies in the Tapering
Anti-Psychotics and Evaluating Recovery Consortium.
Schizophrenia Bulletin, 50(1), 5-8.
https://doi.org/10.1093/schbul/sbad112
King,
B., Kempton, M. J., Broberg, B. V., Merritt, K., Barker, G. J.,
Lythgoe, D. J., Perez-Iglesias, R., Baandrup, L., Düring, S.
W., Stone, J. M., Rostrup, E., Sommer, I. E.,
Glenthøj, B., Kahn, R. S., Dazzan, P., McGuire, P. K., &
Egerton, A. (2024). A letter to the editor: The effects of
alcohol use on brain glutamate in first episode psychosis.
Schizophrenia Research, 266,
234-236. https://doi.org/10.1016/j.schres.2024.02.013
van
Zonneveld, S. M., van den Oever, E. J.,
Haarman, B. C. M., Grandjean, E. L., Nuninga, J.
O., van de Rest, O., & Sommer, I. E. C.
(2024). An Anti-Inflammatory Diet and Its Potential Benefit
for Individuals with Mental Disorders and Neurodegenerative
Diseases—A Narrative Review.
Nutrients, 16(16), Article 2646. https://doi.org/10.3390/nu16162646
de
Haan, L., Gangadin, S. S., de Beer,
F., Djordjevic, M., Begemann, M. J.
H., & Sommer, I. E. C. (2024).
Antipsychotica na een eerste psychose.
Nederlands Tijdschrift voor Geneeskunde,
168, Article D7594. https://www.ntvg.nl/artikelen/antipsychotica-na-een-eerste-psychose
HAMLETT
OPHELIA Consortium, de Beer, F., Wijnen,
B., Wouda, L., Koops, S., Gangadin,
S., Veling, W., van Beveren, N., de Haan,
L., Begemann, M. J. H., Sommer, I. E.
C., & Djordjevic, M. (2024).
Antipsychotic dopamine D2 affinity and negative
symptoms in remitted first episode psychosis patients.
Schizophrenia Research, 274,
299-306. https://doi.org/10.1016/j.schres.2024.09.030
Brand,
B. A., de Boer, J. N., Willemse, E. J.
M., Weickert, C. S., Sommer, I. E., &
Weickert, T. W. (2024). Antipsychotic-induced prolactin
elevation in premenopausal women with schizophrenia: associations
with estrogen, disease severity and cognition.
Archives of Women's Mental Health,
27, 931-941. https://doi.org/10.1007/s00737-024-01491-9
Palominos,
C., He, R., Fröhlich, K., Mülfarth, R. R., Seuffert,
S., Sommer, I. E., Homan, P., Kircher, T., Stein,
F., & Hinzen, W. (2024). Approximating the
semantic space: word embedding techniques in psychiatric speech
analysis. Schizophrenia, 10,
Article 114. https://doi.org/10.1038/s41537-024-00524-7
Zimmermann,
S., Sakreida, K., Bludau, S., Camilleri, J. A., Hoffstaedter, F.,
Pelzer, D. I., Aleman, A., Brückner, T., Derntl,
B., Frank, E., Frodl, T., Fuentes-Claramonte, P.,
García-León, M. Á., Gruber, O., Hajak, G., Heim, S.,
Jardri, R., Kogler, L., Kreuzer, P. M., ... Poeppl, T. B. (2024).
Asymmetry, cytoarchitectonic morphology and genetics
associated with Broca’s area in schizophrenia.
Nature Mental Health, 2(3), 310-319.
https://doi.org/10.1038/s44220-023-00200-2
d'Angremont,
E., van der Zee, S., Slingerland,
S., Slomp, A. C., de Vries, E. F.
J., van Laar, T., & Sommer, I.
E. (2024). Cholinergic deficiency in Parkinson's
disease patients with visual hallucinations. Brain
: a Journal of Neurology, 147(10),
3370–3378. https://doi.org/10.1093/brain/awae186
Marschall,
T. M., Brederoo, S. G., Koops,
S., Ćurčić-Blake, B.,
& Sommer, I. E. C. (2024). Content-based
clustering of hallucinations across sensory modalities in a large
online survey. Scientific Reports,
14, Article 23108. https://doi.org/10.1038/s41598-024-69798-2
Brand,
B. A., Willemse, E. J. M., Hamers, I. M.
H., & Sommer, I. E. (2024).
Correction to: Evidence-Based Recommendations for the
Pharmacological Treatment of Women with Schizophrenia Spectrum
Disorders (Current Psychiatry Reports, (2023), 25, 11, (723-733),
10.1007/s11920-023-01460-6). Current Psychiatry
Reports, 26(10), 550-551. https://doi.org/10.1007/s11920-024-01520-5
Zaki,
J. K., Lago, S. G., Spadaro, B., Rustogi, N., Gangadin, S.
S., Benacek, J., Drexhage, H. A., de Witte, L. D., Kahn, R.
S., Sommer, I. E. C., Bahn, S., & Tomasik, J.
(2024). Exploring peripheral biomarkers of response to
simvastatin supplementation in schizophrenia.
Schizophrenia Research, 266, 66-74.
https://doi.org/10.1016/j.schres.2024.02.011
Solmi,
M., Thompson, T., Estradé, A., Agorastos, A., Radua, J.,
Cortese, S., Dragioti, E., Vancampfort, D., Thygesen, L. C.,
Aschauer, H., Schlögelhofer, M., Aschauer, E., Schneeberger,
A., Huber, C. G., Hasler, G., Conus, P., Cuénod, K. Q. D., von
Känel, R., Arrondo, G., ... Correll, C. U. (2024).
Global and risk-group stratified well-being and mental health
during the COVID-19 pandemic in adults: Results from the
international COH-FIT Study. Psychiatry
Research, 342, Article 115972. https://doi.org/10.1016/j.psychres.2024.115972
Gangadin,
S. S., Enthoven, A. D., van Beveren, N. J.
M., Laman, J. D., & Sommer, I. E. C.
(2024). Immune Dysfunction in Schizophrenia Spectrum
Disorders. Annual Review of Clinical
Psychology, 20(1), 229-257. https://doi.org/10.1146/annurev-clinpsy-081122-013201
Li,
Y., Yolland, C. O. B., Rossell, S. L., Sommer, I. E.
C., & Toh, W. L. (2024). Multisensory
hallucinations and other unusual sensory experiences in the context
of migraine: a systematic review. Journal of
Neurology, 271, 1717–1746. https://doi.org/10.1007/s00415-023-12144-9
Ge,
R., Yu, Y., Qi, Y. X., Fan, Y. N., Chen, S., Gao, C., Haas, S. S.,
New, F., Boomsma, D. I., Brodaty, H., Brouwer, R. M., Buckner, R.,
Caseras, X., Crivello, F., Crone, E. A., Erk, S., Fisher, S. E.,
Franke, B., Glahn, D. C., ... ENIGMA Lifespan Working Group (2024).
Normative modelling of brain morphometry across the lifespan
with CentileBrain: algorithm benchmarking and model
optimisation. The Lancet Digital
Health, 6(3), e211-e221. https://doi.org/10.1016/S2589-7500(23)00250-9
HAMLETT
OPHELIA Consortium, de Beer, F., Koops,
S., Schoevers, R. A., Veling, W.,
van Beveren, N., de Haan, L., & Boonstra, N.
(2024). Psychiatrists effect on positive symptom severity and
daily functioning during pharmacotherapy for first-episode
psychosis patients. Scientific
Reports, 14(1), Article 22871. https://doi.org/10.1038/s41598-024-72678-4
Brand,
B. A., Sommer, I. E., Gangadin, S.
S., Tanskanen, A., Tiihonen, J., & Taipale, H. (2024).
Real-World Effectiveness of Menopausal Hormone Therapy in
Preventing Relapse in Women With Schizophrenia or Schizoaffective
Disorder. The American Journal of
Psychiatry, 181(10), 893-900. https://doi.org/10.1176/appi.ajp.20230850
Ioannou,
M., Borkent, J., Andreu-Sánchez,
S., Wu, J., Fu, J., Sommer,
I. E. C., & Haarman, B. C. M. (2024).
Reproducible gut microbial signatures in bipolar and
schizophrenia spectrum disorders: A metagenome-wide study.
Brain, Behavior, and Immunity, 121,
165-175. https://doi.org/10.1016/j.bbi.2024.07.009
Sommer,
I. E., Brand, B. A., Stuijt, C. C.
M., & Touw, D. J. (2024). Sex
differences need to be considered when treating women with
psychotropic drugs. World psychiatry,
23(1), 151-152. https://doi.org/10.1002/wps.21155
De
jager, J. E., Boesjes, R., Roelandt, G.
H. J., Koliaki, I., Sommer, I. E.
C., Schoevers, R. A., & Nuninga, J.
O. (2024). Shared effects of electroconvulsive shocks
and ketamine on neuroplasticity: A Systematic Review of Animal
Models of Depression. Neuroscience &
Biobehavioral Reviews, 164, Article 105796. https://doi.org/10.1016/j.neubiorev.2024.105796
d'Angremont,
E., Sommer, I. E. C., van der Zee,
S., van Laar, T., de Vries, E. F.
J., & Zijdewind, I. (2024).
Short-latency afferent inhibition as a biomarker of
cholinergic degeneration compared to PET imaging in Parkinson's
disease. Parkinsonism & Related
Disorders, 121, Article 106032. https://doi.org/10.1016/j.parkreldis.2024.106032
Hamers,
I. M. H., Brand, B. A., Begemann, M. J.
H., Weickert, C. S., Weickert, T. W., & Sommer, I.
E. C. (2024). The association of prolactin and gonadal
hormones with cognition and symptoms in men with schizophrenia
spectrum disorder: Divergent effects of testosterone and
estrogen. Schizophrenia Research,
270, 273-280. https://doi.org/10.1016/j.schres.2024.06.022
Brederoo,
S. G., Alderson-Day, B., de Boer, J. N.,
Linszen, M. M. J., & Sommer, I. E. C.
(2024). The experience of felt presence in a general
population sample. British Journal of
Psychiatry, 224(4), 119-121. https://doi.org/10.1192/bjp.2024.7
Khaled,
S. M., Brederoo, S. G., Alabdulla, M., Sommer,
I. E. C., & Woodruff, P. W. (2024). The role of
religiosity types in the phenomenology of hallucinations: A large
cross-sectional community-based study in a predominantly Muslim
society. Schizophrenia Research,
265, 30-38. https://doi.org/10.1016/j.schres.2022.11.003
2023
Toh,
W. L., Yolland, C. O., Li, Y., Sommer, I. E., &
Rossell, S. (2024). Multisensory Hallucinatory Experiences in
Migraine: A Preliminary Basis for Olfactory, Somatic-Tactile, and
Gustatory Auras. Neurology: Clinical
Practice, 14(1), Article e200217. https://doi.org/10.1212/CPJ.0000000000200217
van
der Heijden-Hobus, I. M. W., Rosema, B. S., Vorstman, J. A.
S., Kas, M. J. H., Franke, S. K., Boonstra,
N., & Sommer, I. E. C. (2024).
Personal preferences for treatment and care during and after
a First Episode Psychosis: A qualitative study.
Early intervention in psychiatry,
18(6), 415-424. https://doi.org/10.1111/eip.13477
Fond,
G., Mallet, J., Urbach, M., Benros, M. E., Berk, M., Billeci, M.,
Boyer, L., Correll, C. U., Fornaro, M., Kulkarni, J., Leboyer, M.,
Llorca, P. M., Misdrahi, D., Rey, R., Schürhoff, F., Solmi,
M., Sommer, I. E. C., Stahl, S. M., Pignon, B., &
Berna, F. (2023). Adjunctive agents to antipsychotics in
schizophrenia: A systematic umbrella review and recommendations for
amino acids, hormonal therapies and anti-inflammatory drugs.
BMJ mental health, 26(1), Article
e300771. https://doi.org/10.1136/bmjment-2023-300771
Aleman,
A., & Sommer, I. E. C. (2023).
Advances in Hallucination Research.
Schizophrenia Bulletin, 49(1),
S1-S2. https://doi.org/10.1093/schbul/sbac210
Luykx,
J. J., Gonzalez-Diaz, J. M., Guu, T. W., van der Horst, M. Z., van
Dellen, E., Boks, M. P., Guloksuz, S., DeLisi, L. E., Sommer,
I. E., Cummins, R., Shiers, D., Lee, J., Every-Palmer, S.,
Mhalla, A., Chadly, Z., Chan, S. K. W., Cotes, R. O., Takahashi,
S., Benros, M. E., ... Tiihonen, J. (2023). An international
research agenda for clozapine-resistant schizophrenia.
The Lancet Psychiatry, 10(8),
644-652. https://doi.org/10.1016/S2215-0366(23)00109-8
de
Boer, J. N., Brand, B. A., & Sommer, I. E.
C. (2023). Antipsychotica voor vrouwen: overzicht van
de literatuur en praktijkadviezen. Tijdschrift
voor Psychiatrie, 65(2), 87-94.
Brand,
B. A., Haveman, Y. R. A., de Beer, F., de
Boer, J. N., Dazzan, P., & Sommer, I. E. C.
(2023). Antipsychotic medication for women with schizophrenia
spectrum disorders: CORRIGENDUM. Psychological
Medicine, 53(10), 4832. https://doi.org/10.1017/S0033291723001344
Scheurink,
T. A. W., Borkent, J., Gangadin, S.
S., El Aidy, S., Mandl, R., & Sommer,
I. E. C. (2023). Association between gut permeability,
brain volume, and cognition in healthy participants and patients
with schizophrenia spectrum disorder. Brain and
Behavior, 13(6), Article e3011. https://doi.org/10.1002/brb3.3011
Van
der A, J., De Jager, J. E., van Dellen, E., Mandl, R.
C. W., Somers, M., Boks, M. P. M., Sommer, I. E.
C., & Nuninga, J. O. (2023). Changes
in perfusion, and structure of hippocampal subfields related to
cognitive impairment after ECT: A pilot study using ultra high
field MRI. Journal of Affective
Disorders, 325, 321-328. https://doi.org/10.1016/j.jad.2023.01.016
D'Angremont,
E., Begemann, M. J. H., Van Laar,
T., & Sommer, I. E. C. (2023).
Cholinesterase Inhibitors for Treatment of Psychotic Symptoms
in Alzheimer Disease and Parkinson Disease: A Meta-analysis.
Jama neurology, 80(8), 813-823. https://doi.org/10.1001/jamaneurol.2023.1835
Kruiper,
C., Sommer, I. E. C., Koster, M., Bakker, P. R.,
Durston, S., & Oranje, B. (2023). Clonidine augmentation
in patients with schizophrenia: A double-blind, randomized
placebo-controlled trial. Schizophrenia
Research, 255, 148-154. https://doi.org/10.1016/j.schres.2023.03.039
Ciampelli,
S., Voppel, A. E., de Boer, J.
N., Koops, S., & Sommer, I. E.
C. (2023). Combining automatic speech recognition with
semantic natural language processing in schizophrenia.
Psychiatry Research, 325, Article
115252. https://doi.org/10.1016/j.psychres.2023.115252
Gangadin,
S. S., Germann, M., de Witte, L. D., Gelderman,
K. A., Mandl, R. C. W., & Sommer, I. E. C. (2023).
Complement component 4A protein levels are negatively related
to frontal volumes in patients with schizophrenia spectrum
disorders. Schizophrenia Research,
261, 6-14. https://doi.org/10.1016/j.schres.2023.08.031
Khaled,
S. M., Brederoo, S. G., Yehya, A., Alabdulla, M.,
Woodruff, P. W., & Sommer, I. E. C. (2023).
Cross-cultural Differences in Hallucinations: A Comparison
Between Middle Eastern and European Community-Based Samples.
Schizophrenia Bulletin, 49(1),
S13-S24. https://doi.org/10.1093/schbul/sbac086
Brand,
B. A., Willemse, E. J. M., Hamers, I. M.
H., & Sommer, I. E. (2023).
Evidence-Based Recommendations for the Pharmacological
Treatment of Women with Schizophrenia Spectrum Disorders.
Current Psychiatry Reports, 25(11),
723-733. https://doi.org/10.1007/s11920-023-01460-6
Krudop,
W. A., Voppel, A. E., de Boer, J. N., van Schothorst,
H., Sommer, I. E. C., & Pijnenburg, Y. A. L.
(2023). Geautomatiseerde spraakanalyse bij onderscheiden van
frontotemporale dementie en depressie. Tijdschrift
voor Psychiatrie, 65(3), 193-197.
Kübler,
R., Ormel, P. R., Sommer, I. E. C., Kahn, R. S., &
de Witte, L. D. (2023). Gene expression profiling of
monocytes in recent-onset schizophrenia. Brain,
Behavior, and Immunity, 111, 334-342. https://doi.org/10.1016/j.bbi.2023.04.019
Marschall,
T. M., van Dijk, P., Kluk, K., Koops,
S., Linszen, M. M. J., Griffiths, T. D., Toh,
W. L., Malicka, A. N., Kovačić, D., Mulert, C.,
Sommer, I. E. C., & Ćurčić-Blake,
B. (2023). Hallucinations in Hearing Impairment: How
Informed Are Clinicians? Schizophrenia
Bulletin, 49(S1), S33–S40. https://doi.org/10.1093/schbul/sbac034
Koops,
S., Brederoo, S. G., Voppel, A.
E., & Sommer, I. E. C. (2023).
Herkennen van depressie met computationele
taalanalyse. Tijdschrift voor
Psychiatrie, 65(3), 198-201. https://www.tijdschriftvoorpsychiatrie.nl/nl/artikelen/article/50-13129_Herkennen-van-depressie-met-computationele-taalanalyse
van
den Heuvel, M. P., Ardesch, D. J., Scholtens, L. H., de Lange, S.
C., van Haren, N. E. M., Sommer, I. E. C., Dannlowski,
U., Repple, J., Preuss, T. M., Hopkins, W. D., & Rilling, J. K.
(2023). Human and chimpanzee shared and divergent
neurobiological systems for general and specific cognitive brain
functions. Proceedings of the National Academy of
Sciences of the United States of America,
120(22), Article e2218565120. https://doi.org/10.1073/pnas.2218565120
Tan,
E. J., Sommer, I. E. C., & Palaniyappan, L.
(2023). Language and Psychosis: Tightening the
Association. Schizophrenia Bulletin,
49(2), S83-S85. https://doi.org/10.1093/schbul/sbac211
So,
S. H. W., Chau, A. K. C., Chung, L. K. H., Leung, C. M., Chong, G.
H. C., Chang, W. C., Mak, A. D. P., Chan, S. S. M., Lee, S.,
& Sommer, I. E. (2023). Moment-To-moment affective
dynamics in schizophrenia and bipolar disorder.
European Psychiatry, 66(1), Article
e67. https://doi.org/10.1192/j.eurpsy.2023.2438
Corona
Hernández, H., Corcoran, C., Achim, A. M., de
Boer, J. N., Boerma, T., Brederoo, S. G.,
Cecchi, G. A., Ciampelli, S., Elvevåg, B.,
Fusaroli, R., Giordano, S., Hauglid, M., van Hessen, A., Hinzen,
W., Homan, P., de Kloet, S. F., Koops, S., Kuperberg,
G. R., Maheshwari, K., ... Palaniyappan, L. (2023).
Natural Language Processing Markers for Psychosis and Other
Psychiatric Disorders: Emerging Themes and Research Agenda From a
Cross-Linguistic Workshop. Schizophrenia
Bulletin, 49(2), S86-S92. https://doi.org/10.1093/schbul/sbac215
Jairaj,
C., Seneviratne, G., Bergink, V., Sommer, I. E., &
Dazzan, P. (2023). Postpartum psychosis: A proposed treatment
algorithm. Journal of
Psychopharmacology, 37(10), 960-970. https://doi.org/10.1177/02698811231181573
van
der Weijden-Germann, M., Brederoo, S. G.,
Linszen, M. M. J., & Sommer, I. E. C.
(2023). Recreational Drug Use and Distress From
Hallucinations in the General Dutch Population.
Schizophrenia Bulletin, 49(1),
S41-S47. https://doi.org/10.1093/schbul/sbac190
Borkent,
J., Ioannou, M., Folkertsma,
T., Wardenaar, K. J., Haarman, B. C.
M., van Goor, H., Sommer, I. E.
C., & Bourgonje, A. R. (2023). Serum
free thiols in recently diagnosed patients with schizophrenia
spectrum disorder: a potentially useful biomarker of oxidative
stress. Psychiatry Research,
321, Article 115075. https://doi.org/10.1016/j.psychres.2023.115075
Brederoo,
S. G., de Boer, J. N., Linszen, M. M.
J., Blom, R. E., Begemann, M. J. H.,
& Sommer, I. E. C. (2023). Social Deafferentation
and the Relation Between Loneliness and Hallucinations.
Schizophrenia Bulletin, 49(1),
S25-S32. https://doi.org/10.1093/schbul/sbac064
Ciampelli,
S., de Boer, J. N., Voppel, A.
E., Corona Hernandez, H., Brederoo, S.
G., van Dellen, E., Mota, N. B., & Sommer, I. E.
C. (2023). Syntactic Network Analysis in
Schizophrenia-Spectrum Disorders. Schizophrenia
Bulletin, 49(2), S172-S182. https://doi.org/10.1093/schbul/sbac194
Yehya,
A., Khaled, S. M., Sommer, I. E. C., Elhag, S. F.,
Hassan, M. H. M. O., Woodruff, P., & Alabdalla, M. (2023).
The Arabic Questionnaire for Psychotic Experiences in
patients with psychotic disorders: a clinical validation.
BMC Psychiatry, 23(1), Article 141.
https://doi.org/10.1186/s12888-023-04649-4
2022
Gangadin,
S. S., Mandl, R. C. W., de Witte, L. D., van Haren, N. E.
M., Schutte, M. J. L., Begemann, M. J.
H., Kahn, R. S., & Sommer, I. E. C. (2024).
Lower fractional anisotropy without evidence for
neuro-inflammation in patients with early-phase schizophrenia
spectrum disorders. Schizophrenia
Research, 264, 557-566. https://doi.org/10.1016/j.schres.2022.12.009
Corona
Hernández, H., de Boer, J.,
Brederoo, S., Voppel, A., & Sommer,
I. E. C. (2023). Assessing coherence through
linguistic connectives: Analysis of speech in patients with
schizophrenia-spectrum disorders. Schizophrenia
Research, 259, 48-58. https://doi.org/10.1016/j.schres.2022.06.013
Hugdahl,
K., Craven, A. R., Johnsen, E., Ersland, L., Stoyanov, D.,
Kandilarova, S., Sandoy, L. B., Kroken, R. A., Loberg, E.-M.,
& Sommer, I. E. (2023). Neural Activation in the
Ventromedial Prefrontal Cortex Precedes Conscious Experience of
Being in or Out of a Transient Hallucinatory State.
Schizophrenia Bulletin, 49(1),
S58–S67. https://doi.org/10.1093/schbul/sbac028
Voppel,
A. E., de Boer, J. N., Brederoo, S.
G., Schnack, H. G., & Sommer, I. E. C.
(2023). Semantic and Acoustic Markers in
Schizophrenia-Spectrum Disorders: A Combinatory Machine Learning
Approach. Schizophrenia Bulletin,
49(2), S163-S171. https://doi.org/10.1093/schbul/sbac142
2021
de
Boer, J. N., Voppel, A. E., Brederoo, S.
G., Schnack, H. G., Truong, K. P., Wijnen, F. N. K.,
& Sommer, I. E. C. (2023). Acoustic speech markers
for schizophrenia-spectrum disorders: a diagnostic and
symptom-recognition tool. Psychological
Medicine, 53(4), 1302–1312. https://doi.org/10.1017/S0033291721002804
Begemann,
M. J. H., Schutte, M. J. L., Van Dellen, E.,
Abramovic, L., Boks, M. P., Van Haren, N. E. M., Mandl, R. C. W.,
Vinkers, C. H., Bohlken, M. M., & Sommer, I. E. C.
(2023). Childhood trauma is associated with reduced frontal
gray matter volume: A large transdiagnostic structural MRI
study. Psychological Medicine,
53(3), 741-749. https://doi.org/10.1017/S0033291721002087
Oomen,
P. P., Begemann, M. J. H., Brand, B.
A., de Haan, L., Veling, W., Koops,
S., van Os, J., Smit, F., Bakker, P. R., van Beveren,
N., Boonstra, N., Gülöksüz, S.,
Kikkert, M., Lokkerbol, J., Marcelis, M.,
Rosema, B.-S., de Beer, F., Gangadin, S.
S., Geraets, C. N. W., ... Sommer, I. E.
C. (2023). Longitudinal clinical and functional
outcome in distinct cognitive subgroups of first-episode psychosis:
a cluster analysis. Psychological
Medicine, 53(6), 2317 - 2327. https://doi.org/10.1017/S0033291721004153
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