Butterflies or Red Flags?

That electric, can't-eat-can't-sleep feeling when you meet someone new? Culture calls it chemistry. Neuroscience calls it hyperarousal.

Early in love, studies have found lower serotonin-transporter density in platelets, resembling findings reported in obsessive-compulsive disorder. That may help explain why thoughts feel sticky and intense. It is not destiny — it is neurochemistry in overdrive. If it feels too intense, that is worth paying attention to.