There are several definitions of stalking in the literature, and these share a number of features.
Stalking involves:
(1) the perpetuator (stalker), who shows an abnormal pattern of behavior that is repeatedly directed towards a particular person. The stalker may have a mental illness or personality disorder (obsessive-compulsive, narcissism, other).
(2) the target (stalkee)
(3) The behavior is persistent and extends for some period of time (may last months or years). More than 1 episode is needed to establish the diagnosis.
(4) The behavior of the stalker is unwanted by, unwelcomed by and/or threatening to the person being stalked.
(5) The stalking behavior usually has one or more negative effects on the person being stalked, which may be emotional (unease, fear, distress), physical, economical or social.
If the person being stalked is unaware that she or he is being stalked, then:
(1) it may not have a negative impact
(2) it could still be stalking if the person would not want it to be happening if she or he knew about it
Stalking needs to be distinguished from persistent behaviors where the person stops when it is known that the attention is unwanted or not reciprocated.
