3.8 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Biology of romantic love | 10/14 | https://en.wikipedia.org/wiki/Biology_of_romantic_love | reference | science, encyclopedia | 2026-05-05T15:53:39.742070+00:00 | kb-cron |
Obsessive thinking about a loved one has been called a hallmark or a cardinal trait of romantic love, ensuring that the loved one is not forgotten. Some reports have been made that people can even spend as much as 85 to 100% of their days and nights thinking about a love object. One study found that on average people in love spent 65% of their waking hours thinking about their beloved. Another study used cluster analysis to find several different groups of lovers, with the least intense group spending 35% of their time on average and the most intense at 72%. Since the late 1990s, these obsessional features have been compared to obsessive–compulsive disorder (OCD). This is also sometimes paired with a theory that obsessive (or intrusive) thinking is related to serotonin levels being lowered while in love, although study results have been inconsistent or negative. Another theory relates obsessive thinking to addiction, because drug users exhibit obsessive thoughts about drug use as well as compulsions. In 1999, James Leckman and Linda Mayes published a theoretical comparison between early-stage romantic love, early parental love, and OCD. This paper was intended as an investigation into the origin of OCD, but it also relates to the evolutionary theory of romantic love. Both early-stage romantic love and OCD share features of preoccupation, intrusive thoughts, a heightened sense of responsibility, a need for things to be "just right", and some proximity-seeking behaviors. In some cases, obsessions experienced by OCD patients relate to what harms might happen to a family member, which resembles some behavioral patterns involved with romantic and parental love. The authors also speculate that psychasthenia (feelings of incompleteness, insufficiency, or imperfection) resembles the "longing for reciprocity" and idealization which are features of romantic love. Two experiments have investigated whether there is a relationship between romantic love and serotonin levels, by taking different measures using blood samples. Although serotonin levels in the central nervous system would actually be the measure of interest, it has been assumed that measures of peripheral serotonin can be used as a marker for this. A 1999 experiment led by Donatella Marazziti found that people in love had platelet serotonin transporter (SERT) density which was lower than controls, and similar to the density of a group of unmedicated OCD patients. Six of the 20 in-love participants were also retested after a period of 12 to 18 months, and SERT density had returned to normal. However, because Marazziti's experiment looked at SERT (rather than serotonin directly), this makes it ambiguous whether serotonin levels were actually higher or lower. SERT transports serotonin from blood plasma back into the platelets, so that a reduction in SERT could correspond to an increased plasma level. Another experiment in 2012 led by Sandra Langeslag which looked at blood serotonin levels found a contradictory result, with men and women being affected differently. Men had lower serotonin levels than controls, but women had higher serotonin levels. In women, obsessive thinking was also actually associated with increased serotonin. A 2025 study led by Adam Bode also found no association between SSRI use and obsessive thinking about a loved one, or the intensity of romantic love. Therefore, although the earlier experiments do suggest romantic love and serotonin are probably associated, the authors suggest that the idea of obsessive thinking being attributed to lowered serotonin levels seems inaccurate.