Psychotherapy leaves measurable molecular signature in blood, Spanish study finds

Psychotherapy produces measurable biological changes that can be detected in blood, according to a preliminary Spanish study that researchers say could eventually help personalize non-drug treatments for people with major depression.

"What this study demonstrates is that psychological therapies act as specific biological stimuli, producing distinct molecular changes in the blood," co-lead researcher Analia Bortolozzi said in a statement published Thursday by the Spanish National Research Council (CSIC).

The preliminary study, published in Scientific Reports, found that different forms of psychological therapy triggered distinct changes in microRNAs – small molecules that regulate gene activity – which could be detected in blood samples.

Researchers from CSIC and the Sant Pau Research Institute analyzed blood samples from 22 patients with major depressive disorder before and after 12 weeks of psychotherapy at Barcelona's Hospital de la Santa Creu i Sant Pau. ​​​​​​​

The team compared two common non-drug treatments: integral cognitive remediation (INCREM), which aims to improve functions such as attention and memory, and psychoeducation, which helps patients better understand and manage their condition.

Patients who received cognitive remediation developed a distinct pattern involving seven microRNAs linked to neuroplasticity, brain signaling and cognition. Those molecular changes were accompanied by measurable improvements in cognitive performance.

By contrast, psychoeducation produced a different molecular signature involving two microRNAs associated with cellular resilience to stress, although researchers did not observe the same direct cognitive improvements.

"The findings lay a promising foundation for the development of blood biomarkers that could track cognitive recovery," co-lead researcher Maria Portella said.

The researchers said the approach could eventually support more personalized treatment for major depressive disorder by helping doctors tailor psychological therapies based on a patient's biological profile rather than relying largely on trial and error.

The authors cautioned that the findings are preliminary and need to be validated in larger studies before they can be applied in clinical practice.

The findings add to growing research into the role of microRNAs in psychiatric and neurological disorders.

Last year, a study published in Nature Aging identified, for the first time, specific microRNAs likely involved in the development of bipolar disorder, depression, schizophrenia, post-traumatic stress disorder (PTSD) and Parkinson's disease.