There is evidence that selective serotonin reuptake inhibitors (SSRIs) which are used as antidepressants can increase the risk of bleeding in the upper gastrointestinal tract. However, more research is needed and a UK study of 11,321 patients has found that SSRIs did increase the risk of gastrointestinal bleeding particularly when people were also using nonsteroidal anti-inflammatory drugs. However, using other acid-suppressing drugs reduced the risk of bleeding.
de Abajo, Franciso J. and Garcia-Rodriguez, Luis A. - Risk of upper gastrointestinal tract bleeding associated with serotonin reuptake inhibitors and venlafaxine therapy: interaction with nonsteroidal anti-inflammatory drugs and effect of acid-suppressing agents Archives of General Psychiatry July 2008, 65(7), 795-803