Stalking is now used to describe a problem behaviour characterized by repeatedly inflicting unwanted intrusions and/or communications on another in a manner which creates fear and/or significant distress.⁽¹⁾ The intrusions can involve, following, loitering nearby, maintaining surveillance, and making approaches. The communication can be via telephone (including SMS), letter, electronic mail, graffiti and notes attached, for example, to the victims’ car. Stalking can be associated with a range of harassments which though not part of the core behaviours are all too frequent. These include, ordering goods and services on the victim’s behalf (late night pizza’s being a favourite) damaging property, spreading malicious rumours, vexatious complaints, threats, ‘cyber terrorism’, and assault.

There are two basic patterns to stalking.⁽²⁾ The first involves repeated incursions predominantly in the form of approaches and following perpetrated most often by a stranger and lasting only a day or so. The second is characterized by a range of both communications and intrusions, is usually perpetrated by an ex-intimate or acquaintance, and lasts for weeks, months, or even years. The first type can be intense and distressing at the time but uncommonly culminates in a physical attack and though upsetting, rarely inflicts long-term psychological or social damage. The second type is associated not infrequently with psychological and social damage to the victim and will involve physical assaults in up to a third of victims.

Estimates of the prevalence of stalking, as with any other phenomenon, will vary according to definition, sampling, method of enquiry, and the willingness of subjects to respond and respond frankly.^{(2,3,4,5,6,7)} Reported lifetime rates of victimization for women are between 8 per cent and 22 per cent and for men between 2 per cent and 8 per cent. Most victims are female (70-80 per cent), most stalkers are male (80-85 per cent), with 20-25 per cent involving same gender stalking, typically male on male.

Cyberstalking has attracted considerable interest but few systematic studies. Even the definitions employed of cyberstalking vary widely.^(8,9,10) As befits an online phenomenon much of the information about it is to be found on the Internet rather than in the more traditional sources of academic knowledge.

Sheridan and colleagues⁽¹¹⁾ in an important study concluded that cyberstalking was usually one more invasive technique for pursuing stalking rather than a distinct type of activity.

Cyberstalking can include the use of the Internet and SMS facilities to:

1 Send repeated unwanted messages.

2 Order goods and services on the victim’s behalf.

3 Publicizing private information of a potentially damaging or embarrassing nature. Including circulating e-mails, placing information on the web containing personal details, and occasionally explicit sexual images.

4 Spreading false information. A wide range of misinformation can be spread via the Internet with the authors of these calumnies able, should they wish and have the necessary skills, to hide their identity.

5 Information gathering online about a victim can cover a wide range of material from addresses, employment histories, to financial details. There are even services for tracing people available online which can be utilized by stalkers whose victim has eluded them.

6 Identity theft goes beyond simply pretending to be the victim for the purposes of ordering goods or initiating contacts to an attempt to assume not just the name but the actual property and attributes of the victim.

7 Encouraging others to harass the victim. This can cover activities such as placing communication purporting to be from the victim on web likely to attract unwanted communications or attentions. The most egregious example involved a rejected stalker who posted personal advertisements in his ex-partner’s name and giving her address which suggested she enjoyed being raped and solicited such attentions. Apparently six men actually came to her house in response to these provocations.⁽¹²⁾

Stalking is both an act of violence in itself which causes psychological distress and social disruption, and is a harbinger of assault. Being stalked can produce a corrosive state of fear, arousal, and
helplessness. As with domestic violence for most victims it is not the blows which are the most destructive but living in a chronic state of intimidation and the expectation of imminent intrusion. In the study of Pathé and Mullen⁽¹³⁾ the majority reported disruptive levels of anxiety with intrusive recollections of the stalking, sleep disturbance, lowered mood, with 25 per cent admitting considering suicide to escape the situation. A community study found increased rates of psychiatric morbidity and post-traumatic symptomatology amongst those stalked for more than 2 weeks but not amongst those who had experienced the briefer periods of harassment.⁽¹⁴⁾ Dressing and colleagues^(7,15) also document significant psychological and social disruption in response to being stalked with 56 per cent reporting agitation, 44 per cent increased anxiety, 41 per cent sleep problems, and 28 per cent increased depression.

Stalking, like most forms of complex human behaviour, can be the outcome of a wide range of psychological, social, and cultural influences. Some stalk in hope, some in anger, some in lust, some in ignorance, and many in mixtures of the above. In an attempt to advance the understanding of stalkers a range of typologies and classifications have been advanced.⁽¹⁶⁾

Classifying stalkers by the nature of their prior relationship with the victim has the advantages of simplicity and utility. The classification advanced by Mohandie and colleagues⁽¹⁷⁾ represent the best supported by empirical evidence of such approaches to date. They divide stalkers into those with and without a prior relationship. Those with a prior relationship are subdivided into ex-intimates (ex-partners both long term and more casual) and acquaintances (including friends, colleagues, and professional contacts). Those without a prior relationship are subdivided into firstly ‘public strangers’ who were encountered through the media or in their public roles, and secondly into ‘private strangers’ encountered by chance in the interactions of everyday life. This classification’s greatest utility is in predicting the risks of assault, with those with a prior intimate relationship constituting the highest risk group and those targeting public strangers the lowest. In their view the pursuers of public strangers are the most likely to be psychotic with those pursuing ex-intimates being relatively impervious to therapy but responsive to criminal sanctions.

The typology first developed by Mullen and colleagues^(1,18) depends primarily of the context in which the stalking emerges and the motivations which initiated and sustained the behaviour. Its appeal has been primarily to clinicians managing stalkers and their victims.⁽¹⁹⁾ There are five main types:

1 The rejected whose stalking begins in the context of the breakdown of a close relationship. The stalking is initially motivated either by the desire for reconciliation or to express the rage at rejection, with a mixture of both being quite common. The stalking is often sustained by the pursuit of the ex-partner becoming a substitute for the lost relationship with the satisfactions from intrusion and control replacing those of intimacy.

2 The intimacy-seeker who is pursuing love. The stalking begins in the context of a life bereft of intimacy and is motivated by the hope, or firm expectation, of obtaining a loving relationship with a stranger or casual acquaintance on whom they have fixed their amorous attentions. The pursuit is sustained in the face of indifference or outright rejection because better a love based on fantasy or delusion than no love at all.

3 The incompetent suitor who is pursuing a sexual encounter or friendship. This usually begins in the context of loneliness and is motivated by a desire to start some form of relationship with someone who has attracted their interest. This group often pursues intensely with multiple intrusions but rarely persists for more than a day or so, presumably because multiple rebuffs bring few rewards.

4 The resentful, whose stalking starts in the context of a grievance at being unjustly treated or humiliated. The initial motivation is revenge but this gives way to the satisfactions obtained from the sense of power over someone who has previously been experienced as an oppressor, or the representative of oppressors.

5 The predatory, which begins in the context of the desire to act out violent or sexual fantasies often of a sadistic or paedophilic nature. The initial motivation is to gain information about the movements of a potential victim (usually a stranger but occasionally an acquaintance). The stalking continues because of the satisfactions accruing not just from voyeurism but from the excitement and sense of power which comes from rehearsing the planned attack in fantasy whilst watching the future victim.

Each of the stalker types, hopefully with the exception of the predatory, has correlates in normal behaviour. When relationships break down one partner is often confused or distressed by the separation and seeks to understand, to reconcile, or to express anger. The incompetent suitor is kin to the awkward adolescent male and the socially inept adult who fails to traverse effectively the social minefields of courting or simply making acquaintance. The intimacy seeker is the adolescent crush and the enthusiastic fan writ large. Even the resentful is not far removed from some seekers after justice and those asserting their rights. In theory the boundary between persistent approaches as part of socially acceptable behaviour and the crime of stalking are difficult to pin down. In practice the distinction is rarely a problem. Stalkers are those who repeatedly force themselves on another person in a manner which creates obvious distress. It is the total disregard, or blindness to, the disturbance and often fear that their behaviour creates which distinguishes the stalker from their more normal counterparts. Sometimes the stalkers are so caught up in their own world they are oblivious to their effect on others. Sometimes they are blinded by delusion. Sometimes self-righteousness makes them indifferent. But sometimes they delight in the effect they produce in their victim.

Stalkers are rarely, if ever, drawn from the psychologically adequate or socially able of the world. The estimates of the proportion of stalkers whose behaviour is directly related to mental disorders varies according to where the researchers derived their sample. For example, Zona and his group⁽²⁰⁾ whose sample contained many who pursued Hollywood celebrities had a significant number with erotomanias and morbid infatuations.

In broad terms psychotic disorders are relatively frequent in the intimacy seeking group. In the resentful type it is the paranoid
disorders which unsurprisingly predominate, though most are not associated with frank delusion. The rejected often have problems around dependency, rigidity, control, and self-esteem with substance abuse and depressive states on occasion complicating the picture, but psychotic states are uncommon. The incompetent suitors are socially disabled sometimes by shyness, sometimes by narcissism, sometimes by intellectual limitations, sometimes by culture, sometimes by disorders such as Asperger’s syndrome, rarely by psychosis, but always by interpersonal insensitivity or indifference. The predatory are sexually perverse and not infrequently have marked psychopathic traits, but again are rarely psychotic.

Attempts have been made to conceptualize stalking as a manifestation of obsessive-compulsive disorder. Stalkers are certainly often obsessive in the everyday sense of that word in their pursuit of the victim. They rarely however regard their behaviour as unjustified let alone irrational, and few see their persistence as senseless. They may resist the urges to stalk on occasion but for the most part devote themselves wholeheartedly to the pursuit. Anxiety is more likely to be generated by the fear of failure, or of consequences, than by not acting on their impulses to stalk. They may well spend many hours thinking about the object of their unwanted attentions, and in the resentful reliving the experiences of actual or supposed injustice, so in that sense they are ruminators. Personality traits of rigidity, rumination, and the overvaluing of order are not infrequently so marked in rejected and resentful stalkers as to justify a label of an obsessional personality. In short, the behaviour often has an obsessive quality but the state of mind rarely conforms to that found in obsessive-compulsive disorders.

Attachment theory has unsurprisingly been evoked to explain stalking. That stalkers as a group don’t do interpersonal relationships very well is obvious. Evidence exists that insecure attachment styles predominate amongst rejected stalkers, the intimacy seekers may have the type of secure attachment style only sustainable by delusion, and the incompetent and resentful favour the dismissive style. This is useful in assessment and management but what connection it may have with any theory of early development is speculative and here as elsewhere more likely to be productive of mythologizing than good clinical practice.

Health care professionals have a heightened vulnerability to being stalked by their patients and clients.^{(21,22,23,24)} The risk stems largely from resentful and disappointed patients but in part from lonely and disordered people who misconstrue sympathy and attention for romantic interest. While some stalking behaviours constitute little more than minor irritations, they may also ruin a clinician’s career.

Sandberg et al.⁽²⁵⁾ studied an inpatient psychiatric service reporting 53 per cent of clinical staff had been stalked by patients. Galeazzi and colleagues⁽²⁶⁾ found 11 per cent of the mental health professionals in an Italian service had been stalked for lengthy periods by patients. Purcell and colleagues⁽¹⁴⁾ surveyed a randomly selected sample of 1750 psychologists (73 per cent female). The lifetime prevalence of stalking by clients was 19.5 per cent with 8 per cent being stalked in the preceding 12 months. Most victims were working in direct client care (95 per cent) and experienced rather than new entrants to the profession. Stalkers fell predominantly into either the intimacy seeking (19 per cent) or resentful (42 per cent) types. Over 30 per cent of psychologists in this study were subjected to vexatious complaints by their stalker. The impact of complaints to professional boards, health ombudsmen, and other agencies of accountability can be devastating.