Evidence map›Paper›PMID 41142050›Full record

ArticleSchizophrenia research. Cognition2026

Early versus adult onset of schizophrenia: an examination of premorbid and current IQ.

Tereza Calkova, Anja Vaskinn, Lynn Mørch-Johnsen, Runar Elle Smelror, Kjetil Nordbø Jørgensen, Laura A Wortinger, Simon Cervenka, Karin Collste, Beathe Haatveit, Christine Mohn and 8 more

Abstract read
In one paragraph

Article in Schizophrenia research. Cognition, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

18 authors.

Tereza CalkovaCentre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
Anja VaskinnCentre for Precision Psychiatry, Institute of Clinical Medicine, University of Oslo, Norway.
Lynn Mørch-JohnsenNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Runar Elle SmelrorNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Kjetil Nordbø JørgensenNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Laura A WortingerNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Simon CervenkaCentre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
Karin CollsteCentre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
Beathe HaatveitSection for Clinical Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway.
Christine MohnSection for Clinical Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway.
Anne Margrethe MyhreDepartement of Research and innovation, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway.
Erik G JönssonCentre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
Nils Eiel SteenNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Ole A AndreassenNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Ingrid MelleNorwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Ingrid AgartzCentre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
Torill UelandSection for Clinical Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway.
Dimitrios AndreouCentre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: Cognitive deficits are core findings in schizophrenia, but whether the severity of impairments is related to the age of onset remains unclear. We hypothesized that early onset schizophrenia (EOS; onset before age 19) is associated with lower IQ compared to adult-onset schizophrenia (AOS; onset from age 19). Methods: We included 99 adult patients with EOS (age of onset: 15.3 ± 2.8 years), 282 adult patients with AOS (age of onset: 26.5 ± 7.4 years), and 863 adult healthy controls (HC). We assessed current IQ with Wechsler Abbreviated Scale of Intelligence (WASI) and estimated premorbid IQ with National Adult Reading Test (NART). Results: Both patient groups had lower current IQ than HC ( Conclusion: EOS had lower current IQ than AOS, but did not differ in premorbid IQ, suggesting a larger decline from premorbid IQ levels. This could imply different neurodevelopmental processes underlying cognitive dysfunction related to age of onset in schizophrenia, underscoring the necessity for further inquiry into the mechanisms driving this decline and strategies for its prevention.

Indexed as

Adult onset schizophreniaCognitionEarly onset schizophreniaIQ

Identifiers

PMID41142050
PMCPMC12549396

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.