WASHINGTON (dpa-AFX) - A new study suggests that cancer patients taking common antidepressants may have a lower risk of death after starting immunotherapy.
Researchers studied adults with depression or anxiety and solid tumors who began treatment with immune checkpoint inhibitors between 2015 and 2025. The study compared 1,567 patients taking selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, sertraline and escitalopram, with 1,567 patients taking benzodiazepines, which are commonly prescribed for anxiety and sleep problems.
During two years of follow-up, 23.5% of SSRI users died, compared with 34.4% of benzodiazepine users. After accounting for when deaths occurred, SSRI use was linked to about a 37% lower risk of death. However, this does not mean patients lived 37% longer.
Published in PLOS Medicine, the study explained that serotonin may play a role because cancer-fighting T cells can respond to the chemical messenger.
Another analysis of more than 8,000 tumor samples also found a possible link between serotonin-related activity and immune responses in tumors.
However, the findings do not prove that SSRIs improve cancer survival or change immune activity inside tumors as the samples analyzed came from different patients, and the study was based on medical records.
Meanwhile, thyroid problems were more common among SSRI users, affecting 31.6% compared with 26.7% of benzodiazepine users. Other immune-related side effects showed no significant difference.
Researchers said clinical trials are needed to determine whether SSRIs can directly improve cancer outcomes and to better understand their effects on tumors and the immune system.
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