Unlucky in love? Finding romance may be even harder if you take antidepressants. While it is common knowledge that antidepressants such as Zoloft and Prozac can cause sexual dysfunction, new evidence suggests that they can suppress basic emotions of love and romance.

Biological anthropologist Helen Fisher of Rutgers University and UVA psychiatrist James Thomson (Med ’74) theorize that the possibility of love itself is blunted by SSRIs (selective serotonin reuptake inhibitors), the most common type of antidepressant. They say they’ve seen evidence that antidepressants alter brain chemistry in a way that reduces the chance a person can fall in love or feel strong romantic attachment.

Antidepressants lift mood by boosting the brain’s levels of serotonin, a mood-regulating neurotransmitter that also suppresses sexual desire in many people. These drugs also decrease levels of the neurotransmitter dopamine, which plays a role in a range of cognitive and behavioral processes, including desire and arousal.

“There are all sorts of unconscious systems in our brain that we use to negotiate romantic love and romantic attraction,” Thomson tells Wired Science. “If these drugs cause conscious sexual side effects, we’d argue that there are going to be side effects that are not conscious.”

Couples in love show jumps in dopamine-related brain activity at the sight of each other, and that brain activity remains active when the relationship deepens into long-term affection. Still, scientists don’t know how love affects the brain and vice versa.

To date, clinical studies of antidepressants have focused on sexual problems, which are easier to quantify than that ineffable feeling of a romantic spark.