What makes stalkers keep on stalking?

One of the most important factors in dealing with stalkers and protecting their victims is the likelihood of stalkers persisting in their behaviour. A team of researchers led by David V. James from the North London Forensic Service studied 275 people who had come to the police's attention for stalking members of the royal family and 211 people who had been referred to a community forensic mental health clinic as a result of their stalking. They found that the most important factors associated with persistence were psychotic illness, intimacy-seeking motivation and using multiple or intrusive forms of communication.

James, David V. ... [et al] - Persistence in stalking: a comparison of association in general forensic and public figure samples Journal of Forensic Psychiatry and Psychology April 2010, 21(2), 283-305