Psychiatric patients using serotonin reuptake inhibitors (SRI) — a commonly used type of antidepressant — show significantly decreased ventricle volume after one month, according to new neuroimaging research published in the journal Chronic Stress.
The ventricles are a series of four interconnected cerebrospinal fluid-filled cavities that are located within the brain. Several psychiatry disorders are associated with the enlargement of these ventricles, which appears to be the result of a loss of neurons and/or glia, specialized cells that provide support and protection to the neurons.
“We look for biomarkers of psychiatric disease. Despite mental health being incredibly important (for example, suicide is the second cause of death in America for those between 10 and 44 years old), psychiatry is the only medical field in which we don’t have biomarkers to drive diagnoses,” explained study author Ramiro Salas, an associate professor at Baylor College of Medicine and The Menninger Clinic, and a research scientist at the Michael E. DeBakey VA Medical Center in Houston.
“We try to study on one end, biomarkers that are very specific of a disorder or a symptom, and on the other end, biomarkers that are associated with general mental health. Ventricle volume is one possible broad biomarker. It is known that enlarged ventricles are associated with all kinds of bad outcomes, including Alzheimer’s, Parkinson’s, dementia, high anxiety, and many more.”
The study included 80 participants with no history of mental illness and 81 psychiatric inpatients. About half of the inpatients were prescribed and consistently taking SRIs, while the other half did not take any SRI medication during their participation. The researchers used magnetic resonance imaging to assess brain ventricle volumes.
“We studied ventricle volume in patients at The Menninger Clinic, a psychiatric hospital in Houston where patients tend to stay for longer times than typical in psychiatric care. This allowed us to study ventricle volume twice, close to the beginning of treatment and about a month later,” Salas said.
The researchers observed statistically significant reductions in the brain ventricular volumes among patients taking SRIs. The brain ventricles of these participants became relatively more similar to the brain ventricles of healthy controls. Among patients who were not taking SRIs, in contrast, there was no significant changes in ventricular volume.
“We found that treatment at the clinic significantly decreased ventricle volume, but only on those patients taking SRIs,” Salas told PsyPost. “Importantly, we compared patients taking SRIs or not, but the results were not influenced by depression itself.”
The findings provide evidence that “the volume of the brain ventricles can be seen as a general biomarker of brain health,” he added. “We showed that intensive psychological treatment, coupled with SRIs, made the ventricles smaller. This gives hope that treatments can reverse some of the negative changes that happen to the brain associated with psychiatric illness.”
The researchers were surprised to find a “clear separation” between the patients taking SRIs and patients not taking SRIs. “We now want to study whether it is SRIs that made the trick, or the combination between SRI and treatment,” Salas said. “The Menninger Clinic is know for extended inpatient intensive treatment and this may interact with the medication effects. We would like to perform similar studies in different types of clinics.”
The findings are in line with previous research, which has found that antidepressant use is associated with increased cortical thickness, especially in the prefrontal, parietal, and temporal lobes. But the new study, like all research, also includes some caveats.
“Even if our study sample is relatively large for this kind of study, in brain imaging one must always take results as preliminary until somehow corroborated independently,” Salas explained. “Another caveat is the fact that although all patients improved during treatment according to self-report, we did not find clear significant correlations between ventricle volume decrease and self-reported improvements in depression or anxiety. We believe that perhaps a larger sample, or more unbiased measures of improvement could help this issue.”
“This was done with funding from the McNair Foundation in Houston, Texas,” the researcher added.
The study, “Decreased Brain Ventricular Volume in Psychiatric Inpatients with Serotonin Reuptake Inhibitor Treatment“, was authored by PK Bolin, SN Gosnell, K. Brandel-Ankrapp, N. Srinivasan, A. Castellanos, and R. Salas.