“Erotomania” is a type of delusion where the affected person believes another individual is in love with him or her.

Erotomania is a type of delusion in which the affected person believes that another person, usually a stranger, high-status or famous person, is in love with him or her.erotomanic patient believes that a “secret admirer” is declaring his or her affection to the patient, often by special glances, signals, telepathy, or messages through the media. Usually the patient then returns the perceived affection by means of letters, phone calls, gifts, and visits to the unwitting recipient. Even though these advances are unexpected and unwanted, any denial of affection by the object of this delusional love is dismissed by the patient as a ploy to conceal the forbidden love from the rest of the world.

Erotomania Symptoms

• Delusions – this is the main symptom of this psychological condition
• Harassing behavior – due to the fact that the afflicted wants to pursue the person they desire because they cannot accept that there is no romantic relationship that exists between the both of them, the afflicted resort to stalk their victim and might eventually harass them. 
• Stalking – this symptom of erotomania can be expressed through special glances, signals, or mental telepathy.

Erotomania Causes
There is not solid cause has been verified by psychologist but the most widely accepted theories that they have formulated is that erotomania rooted since childhood. The lack of affection during childhood is the most plausible hypothesis.however some doctors said this is most common with females.

Erotomania Treatment
Pharmacological therapy
The use of antipsychotic drugs may help manage the symptoms of delusion.
Erotomania is something that should not be taken for granted because the afflicted individual would surely pose harm to people who are the object of their emotions. In addition, people who are erotomanic thinks that what they are thinking is true, so it is quite difficult to make them understand that what they have in mind is exactly right.
[Source,wiki]