Summary: New research reports increased levels of Alzheimer’s-related tau protein in children and adolescents with early onset psychosis.

Source: IEPA

Higher Levels of Alzheimer’s-Related Tau Found in Young People With Early Onset Psychosis

New findings presented at the International Early Psychosis Association (IEPA) meeting in Milan, Italy (October 20–22) indicate that a specific form of the tau protein associated with Alzheimer’s disease is elevated in patients aged 18 and under who have early onset psychosis (EOP). The study was conducted by Dr. Mathias Lundberg, Dr. Neil Cleland and colleagues at Karolinska Institutet, Stockholm, Sweden.

Early onset psychosis (EOP), which includes early-onset schizophrenia (EOS) and other affective psychotic disorders beginning before age 18, is a group of severe psychiatric conditions whose causes remain largely unknown. Young people afflicted by these disorders frequently experience substantial declines in cognitive abilities—such as attention, executive function, coordination of thought, and working memory—soon after illness onset. This pattern has led researchers to consider whether neurodegenerative processes may contribute to EOP.

In many neurodegenerative diseases, including Alzheimer’s disease, changes in the brain are reflected by measurable increases in specific proteins in blood or cerebrospinal fluid. Tau proteins, and particular fragments or cleaved forms of tau, have been widely studied as biomarkers of neuronal injury and degeneration. The present study aimed to assess whether markers of tau metabolism are altered in adolescents with EOP by measuring two tau-related biomarkers in blood plasma: total tau (t-tau) and caspase-cleaved tau (c-tau). Both markers have been previously associated with neurodegenerative conditions and with brain injury.

The research team compared plasma concentrations of t-tau and c-tau between adolescents diagnosed with EOP (n = 20) and age-matched healthy controls (n = 20). The main result was an increase in caspase-cleaved tau (c-tau) levels among the EOP group. Mean c-tau values were reported as approximately 2,150 pg/ml in the EOP patients versus about 1,100 pg/ml in the control group. Levels of total tau (t-tau) did not show a statistically significant difference between patients and controls in this sample.

These findings suggest that alterations in tau protein metabolism—particularly an increase in caspase-cleaved tau—may be present in early onset psychosis. Because caspase-mediated cleavage of tau is associated with processes of neuronal injury and cell death in neurodegenerative conditions, elevated c-tau in young people with psychosis could reflect underlying neurobiological changes beyond purely functional or developmental explanations.

While the study sample is modest in size, the observed elevation of c-tau warrants further investigation. Replication in larger cohorts, longitudinal follow-up of tau measures over time, and correlation with clinical outcomes and neuroimaging biomarkers would help clarify whether increased c-tau reflects progressive neurodegeneration, transient neuronal stress related to acute illness, or another pathophysiological mechanism specific to early-onset psychosis.

Implications for research and treatment: If further studies confirm that tau metabolism is altered in EOP, this could open new directions for understanding disease mechanisms and for developing targeted interventions. Biomarkers such as c-tau might ultimately contribute to improved diagnosis, monitoring of disease progression, and the evaluation of therapies aimed at protecting neuronal integrity in affected young people.

Funding: The study received support from the Craig H. Neilsen Foundation, the Ray W. Poppleton Endowment, and the National Institutes of Health.

Source: Matthias Lundberg – IEPA
Image source: NeuroscienceNews.com image used for illustrative purposes and noted as public domain in the original report.
Original research presentation: The study was presented at the 10th International Conference on Early Intervention in Mental Health held in Milan, Italy, October 19–22, 2016.

This summary reports results as presented by the investigators. The study found higher mean plasma c-tau in adolescents with early onset psychosis compared with controls and did not find a significant difference in total tau. Further research is needed to determine the clinical significance and potential utility of tau biomarkers in diagnosing or guiding treatment for EOP.