First Relationship Syndrome, also known as FRS, is the condition of being chronically attracted to the first person you enter a relationship with. Being inflicted with said syndrome makes the process of getting over this person when you break up all the more difficult. Common symptoms include constant distraction, sadness, and in more extreme cases, stalking.

First Relationship Syndrome (FRS): the first 'serious' and/or long-term relationship for at least one of the parties in a relationship, leading to constant preoccupation. In many instances this will be the sufferer's first sexual relationship, though this is not always the case.

Symptoms of FRS include:
- constantly discussing partner, or bringing up their name in conversations;
- insisting that they 'cannot be apart' or 'will be together forever';
- fears/paranoia/distrust/jealousy about partner's feelings/actions (though on the other hand sufferer may be totally oblivious to signs of deceit);
- insistence that any actions of the partner are without fault. Includes fierce justification or defensiveness;
- couples or sufferers distancing themselves negatively from social circles or activities. For example, opting to stay in rather than go out "like an old married couple";
- sufferers engaging in the activities/behaviors of their partner, despite never having expressed interest in these activities before;

Long-term FRS-based relationships may deteriorate with time, however both may feel as though they are under pressure to stay committed to the relationship. Either party may be directly responsible for this pressure, but it more commonly stems from a feeling of anxiety about being alone (since they have been together so long). This most commonly occurs in couples where both parties suffered from FRS simultaneously.