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

Who stalks?

There has been a lot of media coverage about stalking lately, some of it very sensationalised but more rigorous scientific studies have also confirmed substantial rates of stalking in the UK. The 1998 British Crime Survey found that 12% of respondents of both sexes had suffered persistent and unwanted attention at some time over the age of 16 and the 2001 British Crime Survey found that 8% of women and 6% of men had been stalked during the past year. However, understanding of the nature of stalking behaviours has not kept pace with the increasing awareness of stalking and much of the research into it has looked at victims rather than perpetrators. A study of 362 patients admitted to Broadmoor looked at their case histories to identify incidents of stalking. The researchers found that 33 of them (9.1%) could be classified as stalkers. They were mostly male, yound, unmarried, minimally educated and unemployed. They had inflicted a wide range of unwanted intrusions and communications on their victims and both threats (55%) and assaults (45%) were common. The types of stalkers were more or less equally split between intimacy seeking, rejected suitors, resentful and predatory with only a tiny group being incompetent suitors.

Whyte, Sean ... [et al] - Who stalks? A description of patients at a high security hospital with a history of stalking behaviour Criminal Behaviour and Mental Health 2008, 18, 27-38