A recent study published in the prestigious journal “Cell“ sheds new light on well-known and widely used antidepressants. Researchers have shown that preparations from the serotonin reuptake inhibitor (SSRI) group, primarily used to treat depression, can also support the immune system in the fight against cancer. 

A team of researchers has shown that SSRIs increase the effectiveness of T lymphocytes – cells responsible for recognizing and destroying cancer cells. In preclinical studies, it has been observed that treatment with these drugs can reduce the size of tumors by up to more than 50%. 

SSRIs work by increasing levels of serotonin, a neurotransmitter known as the “happy hormone.” Although primarily associated with the nervous system, serotonin also plays an important role in the immune system. Researchers have found that some cancers “turn off” the immune response by breaking down serotonin – a mechanism that can be blocked by the action of SSRIs. 

In particularly promising results, it was shown that combining SSRIs with immunotherapy (e.g., anti-PD-1 antibodies) led not only to inhibition of tumor growth, but in some cases – to complete remission of the disease. This is a potentially groundbreaking discovery that could open a new chapter in cancer treatment. 

Researchers are preparing to start clinical trials with cancer patients to see if similar effects can also be observed in humans.