Evidence map›Paper›PMID 41742091›Full record

ArticleBMC psychiatry2026

Could brain-derived neurotrophic factor, irisin, and peroxisome proliferator-activated receptor-gamma be a pathway in cognitive impairment in schizophrenia?

Hasan Ünver, Evrim Bayrak Oruc, Ezel Yıldırım, Semih Ergisi, Ali Yalçındağ, Aysegül Dağdeviren, Sibel Örsel, Gamze Erzin

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

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

8 authors.

Hasan ÜnverDepartment of Psychiatry, Ankara Etlik City Hospital, Ankara, Türkiye.ORCID 0000-0001-5392-5507
Evrim Bayrak OrucMood Disorders Program, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.ORCID 0000-0002-3406-3443
Ezel YıldırımPsychiatry, Bakırkoy Mental Health Hospital, Istanbul, Türkiye.ORCID 0000-0001-9089-069X
Semih ErgisiMethodology Department, Turkish Statistical Institute, Istanbul, Türkiye.ORCID 0009-0007-1364-1252
Ali YalçındağBiochemistry, Ankara Research and Training Hospital, Ankara, Türkiye.ORCID 0000-0003-1846-9248
Aysegül DağdevirenDepartment of Psychiatry, Ankara Etlik City Hospital, Ankara, Türkiye.ORCID 0009-0002-2884-3838
Sibel ÖrselDepartment of Psychiatry, Ankara Etlik City Hospital, Ankara, Türkiye.ORCID 0000-0003-0184-7038
Gamze ErzinInstitute of Health Sciences, Interdisciplinary Neuroscience Department, Ankara University, Ankara, Türkiye. gamze.erzin@gmail.com.ORCID 0000-0001-8002-5053

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivePrevious research has indicated the brain-derived neurotrophic factor (BDNF) level is lower in schizophrenia and associated with cognitive impairment. Irisin-BDNF axis may strengthen learning and memory functions. This study examined associations between BDNF, peroxisome proliferator-activated receptor-gamma (PPAR gamma) and irisin with cognitive deficits in schizophrenia.

methodsWe enrolled 80 patients with schizophrenia and 80 healthy controls (HCs). The enzyme-linked immunosorbent assay (ELISA) method was used for biochemical analysis. The Stroop Test, Trail Making Test (TMT), and Verbal Fluency Test (VFT) were used for cognitive assessment. Statistical analyses included t-tests, correlations, and analysis of covariance (ANCOVA) controlling key confounders.

resultsIn unadjusted analyses, patients had significantly lower BDNF and PPARγ levels than HCs (ps < 0.001). After controlling for covariates, the difference in BDNF was still significant (F = 11804.71, p < 0.001, partial η² = 0.989), but not for PPARγ (F = 1.32, p = 0.252, partial η² = 0.010). Irisin levels did not differ between groups. Patients performed worse on all cognitive tests. After adjustments, deficits in processing speed (TMT-A, F = 4.30, p = 0.040) and executive function (Stroop-3, F = 5.89, p = 0.016; Stroop-4, F = 6.54, p = 0.012) remained significant. Longer illness duration correlated with lower BDNF (r=-0.318, p < 0.01), while more severe negative symptoms correlated with lower irisin (r=-0.244, p < 0.05). No biomarkers-cognition correlations were found groups separately. Exploratory analyses in the combined sample suggested nominal associations, but these did not survive correction for multiple comparisons and controlling for diagnostic group status.

conclusionBDNF demonstrates the most robust association with schizophrenia and cognitive function. The association of PPARγ with schizophrenia is confounded by demographic and metabolic factors, and irisin showed a limited link only to negative symptoms. CLINICAL TRIAL NUMBER: Not applicable.

Indexed as

Brain-Derived Neurotrophic FactorCognitive DysfunctionFibronectinsPPAR gammaSchizophreniaAdultCase-Control StudiesFemaleHumansMaleMiddle AgedNeuropsychological TestsBDNF protein, humanBrain-Derived Neurotrophic FactorFibronectinsFNDC5 protein, humanPPAR gammaBDNFCognitive functionIrisinPPAR gammaSchizophrenia

Identifiers

PMID41742091
PMCPMC13040862

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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.