While antidepressants are already known to cause libido-inhibiting side effects, a new theory suggests they also fundamentally alter the chemistry of love and romance.

Wired reports that selective serotonin reuptake inhibitors (SSRIs) – the most commonly prescribed antidepressants – are widely known to cause sexual dysfunction, but they may also snuff the first sparks between two people otherwise destined to ride into the sunset on a white horse, and prevent couples from bonding.

Antidepressants may cause gastrointestinal (stomach and intestinal) bleeding, spelling more things to not be cheerful about if you’re on them.

According to a Spanish study published in The Archives of General Psychiatry, people taking the Selective Seratonin Reuptake Inhibitors (SSRIs) or Seratonin and Norepinephrine Reuptake Inhibitors (SNRIs) drugs such as Prozac, Paxil, Celexa, Zoloft or Effexor, showed a heightened risk of erosion of the mucous membrane that lines the upper digestive tract.