Alteration of the platelet serotonin transporter in romantic love

Psychol Med. 1999 May;29(3):741-5. doi: 10.1017/s0033291798007946.


Background: The evolutionary consequences of love are so important that there must be some long-established biological process regulating it. Recent findings suggest that the serotonin (5-HT) transporter might be linked to both neuroticism and sexual behaviour as well as to obsessive-compulsive disorder (OCD). The similarities between an overvalued idea, such as that typical of subjects in the early phase of a love relationship, and obsession, prompted us to explore the possibility that the two conditions might share alterations at the level of the 5-HT transporter.

Methods: Twenty subjects who had recently (within the previous 6 months) fallen in love, 20 unmedicated OCD patients and 20 normal controls, were included in the study. The 5-HT transporter was evaluated with the specific binding of 3H-paroxetine (3H-Par) to platelet membranes.

Results: The results showed that the density of 3H-Par binding sites was significantly lower in subjects who had recently fallen in love and in OCD patients than in controls.

Discussion: The main finding of the present study is that subjects who were in the early romantic phase of a love relationship were not different from OCD patients in terms of the density of the platelet 5-HT transporter, which proved to be significantly lower than in the normal controls. This would suggest common neurochemical changes involving the 5-HT system, linked to psychological dimensions shared by the two conditions, perhaps at an ideational level.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Binding Sites
  • Biological Transport / physiology
  • Buffers
  • Female
  • Humans
  • Interpersonal Relations
  • Love*
  • Male
  • Obsessive-Compulsive Disorder / metabolism
  • Paroxetine / pharmacokinetics
  • Serotonin / blood*
  • Serotonin Uptake Inhibitors / pharmacokinetics
  • Sexual Behavior / psychology


  • Buffers
  • Serotonin Uptake Inhibitors
  • Serotonin
  • Paroxetine