BRAIN histamine may play a far greater role in cognition and psychiatric illness than previously recognised, after researchers created the first multiscale map linking brain histamine genes with brain function, development, and mental health disorders across the human lifespan patterns.
Mapping the Brain Histamine System Across Development
Although histamine is best known for its role in allergic reactions, it also acts as a neuromodulator involved in emotion, sleep, memory, and behavioural flexibility. Researchers from King’s College London and the University of Porto investigated how the brain histamine system is organised across cell types, brain regions, developmental stages, and psychiatric disorders. The work aimed to clarify histamine’s contribution to cognition and mental health vulnerability.
Analysis with Genetic and Imaging Data
This multimodal analysis combined transcriptomic, neuroimaging, developmental, and functional datasets. Investigators analysed single-nucleus RNA sequencing data from 49,495 nuclei across multiple cortical regions from the Allen Human Brain Cell Atlas, microarray expression data from six adult postmortem brains aged 24–57 years, and developmental data from 42 neurotypical postmortem brains spanning 8 weeks post-conception to 40 years of age. Positron emission tomography templates were also integrated to compare histaminergic gene expression with neurotransmitter receptor density maps.
Distinct Brain Histamine Patterns Linked to Disorders
Researchers found that histamine receptor H1 and H2 expression was enriched in excitatory neurons, while H3 expression was preferentially identified in inhibitory neuronal populations. A single latent component accounted for 41.1% of variance in core histaminergic gene expression, with higher expression observed in frontal and limbic regions and lower expression in the occipital cortex. This spatial brain histamine signature predicted in vivo H3 receptor binding across independent imaging datasets. Developmentally, histidine decarboxylase expression peaked early, whereas H3 receptor expression increased into adulthood. Histaminergic expression also correlated with structural alteration patterns observed in ADHD, major depressive disorder, schizophrenia, and anorexia nervosa.
Future Therapeutic Directions for Mental Health Research
The findings provide a new framework for investigating how brain histamine signalling may influence psychiatric disease risk and cognitive function. The atlas could support future studies exploring targeted therapies for depression, ADHD, schizophrenia, and other neurodevelopmental or neuropsychiatric conditions.
Reference
Mapping histamine pathway networks in the human brain across cognition and psychiatric disorders. Nature Mental Health. 2026;DOI:10.1038/s44220-026-00637-1.
Featured image: Olga Ко on Adobe Stock
