Some antidepressants may worsen the symptoms of the disease in the initial phase of treatment, because they do not take into account the double signal sent by serotonin cells, informs the Trends in Cognitive Sciences magazine.
It is not uncommon that selective serotonin reuptake inhibitors (SSRIs) – agents commonly used in the pharmacological treatment of depression – exacerbate the course of the disease during the first few days of use (in some patients they increase the risk of suicide), and only after about 2 weeks provide relief from suffering.
Scientists from the University of Otto von Guericke (Germany) found that SSRIs can have this effect because they do not take into account the dual role of serotonin cells, which send a signal that leads on the one hand to the release of serotonin (the neurotransmitter controlling motivation), and on the other hand to the release of glutamate (a neurotransmitter associated with pleasure and learning).
While the serotonergic component is immediately enhanced after the administration of the SSRI, the glutamatergic component is suppressed and only normalizes after a few days of treatment. These different timing mechanisms could help explain the short-term and long-term paradox of SSRIs, says researcher Adrian Fischer.
The dual signaling of serotonin cells may also help to explain another issue, namely why a delay in the therapeutic effects of antidepressants does not occur when patients are administered drugs that target glutamate receptors.
A thorough understanding of these problems can eliminate the side effects of SSRI use and even lead to the development of entirely new drugs. (PAP)