Researchers’ Corner: Tiina Paunio

“My research aims at a better understanding
of the link between sleep and mental health.”

Sleep in psychiatric disorders

Currently, we search for sleep traits in patients with various types of psychiatric disorders: schizophrenia, anxiety and mood disorders, and chronic fatigue. We want to assay the influence of sleep on the disease trajectories and define sleep microstructure characteristics by using sleep laboratory and neuroimaging studies. Our study is based on a hypothesis that sleep and circadian traits can be used for dissecting patients with psychiatric disorders into etiologically more uniform disease subclasses. Further, we hypothesize that these subclasses differ in their prognosis and response to treatment.

This study was stimulated by our recent finding of robust, sleep-based clusters among patients with psychosis in a large SUPER study in Finland as a part of the international Stanley Global Neuropsychiatric Genomic Initiative. Of note, insomnia symptoms were highly correlated with quality of life, an observation which led us also to conduct a clinical trial to treat insomnia symptoms in schizophrenia.

Sleep in development

In two parallel population-based birth cohorts, Child-Sleep and FinnBrain, we have explored the development of sleep and emotional regulation, as well as the underlying genetic mechanisms. Our findings emphasize the importance of sleep, and the interplay of sleep insufficiency with genetic risk factors, in the early development. Currently, we aim to identify EEG- based biomarkers of early life indicators for vulnerability to psychiatric diseases.

Biomarkers for sleep loss

Finally, in a search for finding biomarkers for sleep insufficiency, we identified a distinctive DNA methylation (DNAm) pattern comprising widespread loss of methylation in peripheral blood cells among those with insufficient sleep. In a longitudinal study of shift workers, we found an analogical pattern of hypomethylation linked to sleep insufficiency and disturbed circadian rhythm.

Currently, we examine data from a sleep laboratory study to define the accumulation of DNAm changes during extended sleep loss and its effect on the diurnal rhythms of DNAm. Finding biomarkers for sleep loss would have the potential for a prognostic measure to identify individuals at-risk for long-term health hazards due to insufficient sleep.

Collaboration is needed

Our research requires intensive collaboration between domestic and international experts. With those efforts, we wish to better understand the role of sleep and circadian rhythms in psychiatric disorders, eventually opening avenues for finding new tools in their treatment.