Cognitive Behavioural Psychotherapist.
STALKERS are wreaking havoc in the lives of millions.
What is the psychological makeup of a person that perpetrates such heinous behavior on another?
Stalking, rather than being a condition in and of itself, is a behavior that fits under the umbrella of symptoms for a variety of disorders.
In this article I will examine Stalking. What is the Psychology behind the stalker?
Stalking is a pattern of repeated, unwanted behaviour directed at a specific person that causes them to experience fear, distress, or anxiety. It is not a single act but a course of conduct — phone calls, surveillance, unwanted gifts, threats, or online harassment — that cumulatively creates a climate of fear. In clinical practice, stalking is not a standalone diagnosis; rather, it is a behaviour that emerges from a range of underlying psychological disorders, most commonly personality disorders.
In this article, Dr. John Crimmins — Cognitive Behavioural Psychotherapist and founder of The Behaviour Institute — examines the psychology, typology, and theories that explain why stalkers stalk, and what victims can do to protect themselves.
Stalking is far more widespread than most people realise. The US National Crime Victimization Survey recorded over 5.8 million Americans stalked or harassed in a single year (Baum, Catalano, Rand & Rose, 2009). Across Europe, the EU Agency for Fundamental Rights estimates that one in five women has experienced stalking since the age of 15. Research consistently shows that:
The psychological toll is severe. Research by Pathé and Mullen (1997) found that 83% of stalking victims developed high anxiety, 74% experienced sleep disturbance, and 24% reported suicidal ideation.
Clinical Insight — Dr. John Crimmins, Cognitive Behavioural Psychotherapist
“In my clinical practice, I have worked with many survivors of prolonged stalking, and the physical presentation of trauma never ceases to be striking. One client who came to me after years of sustained stalking was so visibly emaciated from the chronic stress and hypervigilance she had been living under that my initial clinical concern was that I was looking at a presentation of anorexia — it was only through careful assessment that it became clear her physical deterioration was entirely trauma-driven. This case reinforced for me that the body keeps the score in stalking survivorship just as profoundly as in any other form of sustained abuse.”
For behaviour to legally constitute stalking, three conditions must be present simultaneously:
Additionally, the behaviour must occur more than once. A single incident, however frightening, does not legally constitute stalking. Common stalking tactics include:
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The most widely cited classification system for stalkers is Mullen et al.’s (1999) five-type typology, developed through clinical work with over 100 stalkers. Understanding which type is involved has direct implications for risk assessment and safety planning:
The Rejected Stalker
The most common type. Typically a former intimate partner who cannot accept the end of the relationship. Behaviour oscillates between attempts at reconciliation and outright revenge. This type poses the highest risk of physical violence.
The Intimacy Seeker
Pursues a target — often a public figure or someone they barely know — believing a deep romantic relationship either already exists or is destined to develop. Often presents with erotomania: a delusional belief that the target is in love with them.
The Incompetent Suitor
Lacks normal social skills and pursues their target despite clear signals of disinterest. Usually not dangerous, but deeply distressing. Often moves on to new victims if the initial behaviour fails.
The Resentful Stalker
Motivated by a perceived injustice — a grudge against an employer, neighbour, or institution. Stalking is used as a form of retaliation or control. Can be persistent and threatening.
The Predatory Stalker
The most dangerous type. Engages in covert surveillance as preparation for a planned attack, often sexual in nature. The victim is frequently unaware they are being stalked until escalation occurs.
Stalking is not a diagnosis — it is a behaviour. The psychological disorders most commonly found in stalkers include:
Narcissistic Personality Disorder (NPD)
The most prevalent disorder among stalkers. Individuals with NPD have an inflated sense of self-worth and an intense need for admiration. When rejected, they experience a ‘narcissistic injury’ — a profound threat to their self-esteem. Stalking becomes a means of restoring that esteem, either through reconnection or revenge (Meloy, 1999).
Borderline Personality Disorder (BPD)
Characterised by intense emotional instability and an extreme fear of abandonment. Individuals with BPD may engage in stalking behaviour to prevent a real or imagined separation, often oscillating between idealisation and rage toward the victim.
Erotomania (De Clérambault’s Syndrome)
A delusional disorder in which the individual believes — despite all evidence — that another person is in love with them. This disorder underlies many celebrity stalking cases and is notoriously treatment-resistant.
Antisocial Personality Disorder
Associated with the predatory stalker type. A lack of empathy, disregard for others’ rights, and manipulative behaviour are core features. This presentation carries the highest risk of physical harm to the victim.
Substance Use Disorders
Alcohol and drugs lower inhibitions and can trigger psychotic-like episodes, significantly escalating the likelihood of stalking behaviour and violence.
Attachment theory — originating with John Bowlby (1969) and extended by Ainsworth et al. (1978) — provides a powerful explanatory framework for stalking behaviour. The theory holds that early attachment patterns formed with caregivers shape how we relate to others throughout life.
Ainsworth identified three primary attachment styles in childhood:
Bartholomew and Horowitz (1991) extended this into a four-category adult model, adding a ‘preoccupied’ attachment style — characterised by compulsive relationship intrusion — which research has directly linked to stalking behaviour (Dutton & Winstead, 2006).
Cupach & Spitzberg (2004) identified eight distinct clusters of stalking behaviour, ranging from the mildly intrusive to the overtly violent:
Technology has transformed stalking. Where stalkers once had limited means — letters, phone calls, physical presence — the digital age has multiplied their toolkit enormously. Cyberstalking is defined as a pattern of repeated threats, harassment, or unwanted contact via electronic or internet-based technology (Miller, 2012). Modern methods include:
Cyberstalking is particularly prevalent among ex-intimate stalkers, who typically have prior knowledge of passwords and accounts. Research indicates cyberstalkers are less likely to engage in physical approach behaviour — but the psychological harm to victims is equivalent to physical stalking.
Stalking inflicts a wide range of psychological and practical harms:
Effective therapy for stalking survivors requires a careful, trauma-informed approach. The clinician must first establish safety — both practically and psychologically — before any therapeutic processing can begin.
Clinical Insight — Dr. John Crimmins, Cognitive Behavioural Psychotherapist
“As a male therapist working with predominantly female survivors of stalking, one of the most significant clinical challenges I encounter is the establishment of trust. Many of my clients have been so profoundly betrayed and controlled by a man that the therapeutic relationship itself can initially feel threatening — the very gender of the therapist may trigger hypervigilance. I have found that proceeding with patience, radical transparency about the therapeutic process, and a consistently non-directive stance in early sessions is essential to creating the conditions in which meaningful work can begin.”
Clinical Insight — Dr. John Crimmins, Cognitive Behavioural Psychotherapist
“In my practice, I have found that a combined Humanistic and CBT-oriented approach is the most effective framework for working with survivors of stalking. The Humanistic element — rooted in unconditional positive regard, empathy, and the primacy of the client’s own experience — is essential in the early stages of therapy, when the survivor needs to feel genuinely heard and believed before anything else. CBT then provides the structured tools to address the cognitive distortions, hypervigilance, and avoidance behaviours that stalking trauma produces: thought records, behavioural experiments, and gradual exposure work to rebuild a sense of safety in the world. Neither approach alone is sufficient — the warmth of the Humanistic relationship creates the container; the structure of CBT provides the map.”
This integrative approach is supported by the broader trauma literature. Fisher et al. (2016) and the ISTSS guidelines both highlight the importance of stabilisation and therapeutic alliance before trauma processing in complex, prolonged trauma presentations — precisely the profile that long-term stalking produces.
Clinical Insight — Dr. John Crimmins, Cognitive Behavioural Psychotherapist
“One of the most important things I tell colleagues new to working with stalking survivors is this: do not underestimate the duration of therapy required. In my experience, cases involving extreme or long-term stalking — where the victim has lived under surveillance or threat for months or years — consistently require extended therapeutic work.
“Clinically, the research supports what I observe in practice. The NICE guidelines for PTSD recommend a minimum of 8–12 sessions of trauma-focused CBT for single-incident trauma; however, the complex PTSD that frequently develops in prolonged stalking cases typically requires between 20 and 40 sessions, spread across 12 to 24 months, with the possibility of further consolidation work beyond that. Herman’s (1997) three-phase recovery model — safety, remembrance and mourning, and reconnection — in my experience rarely moves through all three phases in under a year of consistent therapeutic engagement.”
Immediate Steps
Practical Measures
Legal Options
Manipulation is a core tool of the stalker, particularly in ex-intimate cases. Common tactics include:
Stalking is a serious, complex behaviour rooted in disordered attachment, personality pathology, and frequently fuelled by rejection and the need for control. Understanding the psychology behind it does not excuse it — but it does help victims recognise patterns, anticipate escalation, and take effective protective action.
Frequently Asked Questions
What mental illness causes stalking?
Stalking is most commonly associated with Narcissistic Personality Disorder, Borderline Personality Disorder, and erotomania (a delusional belief that another person is in love with you). Antisocial Personality Disorder is linked to the most dangerous, predatory stalkers. Substance use disorders can also trigger or escalate stalking behaviour.
Can a stalker love their victim?
Stalkers often believe they love their victim — but what they experience is obsession, not healthy love. Their behaviour is about control, possession, and ego-preservation rather than genuine concern for the other person’s wellbeing. Telling a stalker you don’t love them back rarely stops the behaviour, because their motivation is not reciprocal affection — it is the restoration of their own psychological equilibrium.
Why do stalkers not stop when told to?
Most stalkers operate from a place of profound psychological need — to restore damaged self-esteem, avoid abandonment, or maintain a delusional belief. A refusal can trigger narcissistic injury and actually escalate behaviour in the short term. This is why a single clear no-contact statement followed by total disengagement is more effective than repeated rejections.
Is cyberstalking as serious as physical stalking?
Yes. While cyberstalkers are statistically less likely to physically approach their victims, the psychological harm is equivalent. Loss of privacy, constant surveillance, and reputational damage are deeply traumatic. Cyberstalking also frequently escalates into physical stalking, particularly in ex-intimate cases.
How long does therapy take for stalking survivors?
This depends significantly on the duration and severity of the stalking. For complex or prolonged cases, clinical guidelines suggest that meaningful recovery typically requires between 20 and 40 therapy sessions across 12 to 24 months. This is considerably longer than therapy for single-incident trauma, reflecting the complex PTSD profile that sustained stalking frequently produces.
What should I do first if I think I’m being stalked?
Start a detailed log immediately — record every incident with date, time, location, and description. This documentation is essential for police reports and legal proceedings. Report to police early, even if the behaviour feels insufficiently serious. Early reporting builds an official record that is critical if escalation occurs.
What is the difference between obsession and stalking?
Obsessive thoughts alone do not constitute stalking. Stalking is defined by repeated, unwanted conduct directed at a specific individual that causes fear. The behaviour must be external — acted upon — and must occur more than once.
Can stalkers be treated?
With appropriate intervention, some stalkers — particularly incompetent suitor and intimacy seeker types — can be treated with CBT, medication for underlying conditions, and structured psychotherapy. Predatory and highly narcissistic stalkers are considerably harder to treat. Compliance is the central challenge, as most stalkers do not recognise their behaviour as problematic.
References
Ainsworth, M.D.S., Blehar, M., Waters, E., & Wall, S. (1978). Patterns of attachment. Erlbaum.
Bartholomew, K., & Horowitz, L.M. (1991). Attachment styles among young adults. Journal of Personality and Social Psychology, 61(2), 226–244.
Baum, K., Catalano, S., Rand, M., & Rose, K. (2009). Stalking victimization in the United States. Bureau of Justice Statistics.
Bowlby, J. (1969). Attachment and loss, Vol. 1: Attachment. Basic Books.
Cupach, W.R., & Spitzberg, B.H. (2004). The dark side of relationship pursuit. Lawrence Erlbaum.
Dutton, L.B., & Winstead, B.A. (2006). Predicting unwanted pursuit. Violence & Victims, 21(2), 147–163.
Herman, J.L. (1997). Trauma and recovery. Basic Books.
Meloy, J.R. (1999). Stalking: An old behavior, a new crime. Psychiatric Clinics of North America, 22(1), 85–99.
Miller, L. (2012). Stalking: Patterns, motives, and intervention strategies. Aggression and Violent Behavior.
Mullen, P.E., Pathé, M., Purcell, R., & Stuart, G.W. (1999). A study of stalkers. American Journal of Psychiatry, 156(8), 1244–1249.
NICE (2018). Post-traumatic stress disorder: Management in adults and children. National Institute for Health and Care Excellence.
Owens, J.G. (2016). Why definitions matter: Stalking victimization in the United States. Bureau of Justice Statistics.
Pathé, M., & Mullen, P.E. (1997). The impact of stalkers on their victims. British Journal of Psychiatry, 170, 12–17.
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