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The Singapore Law Gazette

Fifty Shades of Sexual Offending – Part II: Frotteuristic Disorder

From a Frotteur who was convicted and incarcerated for rubbing behaviour:

The sexual arousal that arose in me seemed to have come from some chemical imbalances within me, coupled with some random arousing experiences while growing up. When I was in my teens, I sensed something was wrong but did not understand it. In crowded places like buses and the MRT, there was a mounting sense of arousal that was palpable.

The compulsion to rub or press against someone did indeed bring distress. Even at a young age, I had to fight against the inclination to enter the MRT train or other crowded areas. My mind could also be severely distracted when I was near places which presented “opportunities” for acting out. For instance, I could be in a meeting but my mind would be thinking about a potentially crowded bus-stop when peak hours came along. Socially, it also brought a secret sense of shame, as it was a shameful and undignified thing to admit to. I was immediately ridiculed and disdainfully rejected by a girlfriend when I let slip about my rubbing behaviour on public transport.

What are the things that make frotteuristic behaviour even more potent and debilitating? Top of the list has to be the sense of secrecy that surrounds it. How do I tell my friends, family members or relatives about it without their labelling me as a “pervert“? Confiding in a professional like a psychiatrist is tricky, as I would be admitting to the authorities that I am engaging in behaviours that are deemed illegal. It is not difficult to understand where the fears and hesitation surrounding this condition come from.

If one is susceptible to being visually aroused like me, but does not control the urge to stare at sexually-arousing stimulus, it will only make the compulsive behaviour worse. Over the years, I have come to realise this and in order to not arouse myself, I set a “one-look” rule when I come across ladies with curvy features or those who dressed provocatively. I think what I call this rule should be fairly self-explanatory.

From my experience, other lifestyle alterations can also alleviate the arousal and the chances of “acting out”: it is a must to avoid trains and buses during peak hours as much as possible; distracting myself with other activities like eating, shopping, exercising, social media, etc. also helps to some extent. The adage “out of sight, out of mind” is largely true for me when it comes to grappling with my rubbing impulses.

It boils down to whether I have the presence of mind to remind myself of the legal consequences of acting out and getting caught. As time passes, the mind might go into a “denial” mode and lose its discipline. I believe that regular “probation-style reminders” would help keep up my vigilance.

It’s very easy to be judgmental about people like me who suffer from Frotteuristic Disorder. But the scorn is understandable, considering the emotional distress my behaviour has caused to the victims. I will redouble my efforts to correct myself through professional help. “No More Victims” is my mantra.

* Based on a true story with informed consent given by the Frotteur.

Fifty Shades of Sexual Offending – Part II

Frotteuristic Disorder

It was peak hour. Oblivious to his surroundings, he pressed and rubbed his groin against a woman’s buttocks in the overcrowded MRT train. Nobody seemed to notice as the train was so packed that it was impossible to not have contact with another person. Although he knew what he was doing was not right, he could not control his urge to touch and rub himself against another person. He had tried different methods to stop or distract himself, but the urges were so overpowering that he felt helpless to restrain himself… . He suffers from a condition called Frotteuristic Disorder.

What is Frotteuristic Disorder?

Frotteuristic Disorder is a paraphilic disorder in which an individual derives sexual pleasure and gratification from touching or rubbing himself against a non-consenting person. There is a persistent and intense atypical sexual arousal pattern that is accompanied by clinically significant distress (eg guilt, shame, intense sexual frustration, loneliness) and impairment in functioning (eg social, occupational, and interpersonal). The act of touching or rubbing is undertaken for the purpose of achieving sexual excitement, sometimes followed by orgasm. The act in itself is not deviant or illegal, but the involvement of a non-consenting victim which transgresses interpersonal boundaries makes it so.

Frotteuristic Disorder is often confused with frotteurism or frotteuristic sexual interest. The word Frotteurism is derived from the French verb frotter; it does not have a sexual connotation per se but means the act of rubbing, and was only added to Diagnostic and Statistical Manual of Mental Disorders’ (“DSM”) Paraphilias in 1984 (DSM-IIIR) and subsequent DSM editions. Individuals with frotteuristic sexual interest, however, may not act on their impulses, nor experience any clinically significant distress or psychosocial impairment due to their sexual preferences. For those who like the uninvited touch from strangers, they are considered as having “Frottophilia”.

It is estimated frotteuristic acts may occur in up to 30% of adult males in the general population, with 10-14% of adult males seen in outpatient settings for paraphilic disorders and hypersexuality have a presentation that meets the diagnostic criteria for Frotteuristic Disorder (DSM-5, APA, 2013). Late adolescence and emerging adulthood are the periods where frotteurs often report first becoming aware of their sexual interest in rubbing. Learning theory suggests an initially random or accidental physical contact of a non-consenting person may lead to sexual arousal and excitement; with each successive repetition of the rubbing act reinforcing and perpetuating the frotteuristic behaviour.

Assessment and Diagnosis

Assessment of Frotteuristic Disorder is done by taking a detailed history of one’s psychosexual development which covers compulsive masturbation, compulsive use of pornography, illegal or atypical sexual behaviour and fantasy, urges and propensity to act out sexually, hypersexuality, sexual impulsivity; psychiatric comorbidities, psychosocial impairment and subjective distress. Forensic history of molest, insult or outrage of modesty should be explored in detail. Neuropsychiatric conditions like history of head trauma, medications, substances and neurological conditions relating to sexually aggressive behaviour should be ruled out. Psychometric testing looking at personality attributes and psychopathology, as well as psychophysiological measures like penile plethysmography are employed occasionally.

Diagnostic Criteria of Frotteuristic Disorder (302.89; DSM-5)

  1. Over a period of at least six months, recurrent and intense sexual arousal from touching or rubbing against a non-consenting person, as manifested by fantasies, urges, or behaviours.
  2. The individual has acted on these sexual urges with a non-consenting person, or the sexual urges or fantasies cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

A diagnosis of Frotteuristic Disorder can be made regardless of whether an individual discloses, admit or denies his or her behaviour if there are recurrent frotteuristic behaviour which fulfils the criteria listed above. Multiple arrests and convictions for frotteuristic acts over a considerable period would support the diagnosis.

Frotteuristic Disorder whilst a Paraphilic Disorder, also shares features of Impulse Control Disorders, notably Sexual Compulsivity, and Obsessive-Compulsive Spectrum Disorders. Individuals diagnosed with Frotteuristic Disorder often score very high on scales that measure impulsivity, and reported preoccupation with sexual fantasies of rubbing. Their frotteuristic activities may increase when there are life stressors, and acting out becomes a maladaptive coping strategy. Some frotteurs may become depressed with their out-of-control behaviour, experiencing guilt and shame. Their low mood may cloud their judgment and reduce their impulse control further, which often puts them in potentially hazardous situations of being apprehended.

Psychiatric comorbidities include hypersexuality and other paraphilic disorders, particularly exhibitionistic disorder, voyeuristic disorder and fetishistic disorder / partialism (a paraphilia of sexual interest with an exclusive focus on a specific part of the body other than the genitals). They also may have co-existing social anxiety disorder, are socially inept and experience difficulties dating females (i.e. Courtship Disorder). Conduct disorder, antisocial personality disorder, mood disorders, anxiety disorders and substance use disorders are also common.

A number of risk factors were found to be associated with behavioural manifestation of frotteurism: sexual and physical abuse, deviant sexual fantasy and arousal, brain injury, and anti-sociality (Lussier & Piche, 2008).

Frotteuristic Disorder and Offending

Frotteuristic acts against non-consenting individuals are law-breaking sexual behaviours in most jurisdictions. In Singapore, there is no specific law directed towards frotteurism. Hands-on sexual offences which involve touching, grabbing, kissing or fondling are governed by s 354 of the Penal Code; and are crimes of “assault or use of criminal force to any person, intending to outrage modesty,” equivalent to molestation. The actual act of “outraging someone’s modesty”, however, is not defined by statute. Although a frotteur can be male or female, men are commonly the perpetrators in the touching or rubbing acts, with women being the victims.

Chan, Lim & Ong (1997) in a five-year retrospective study looking into the profile of 157 outrage of modesty (“OM”) offenders remanded to Woodbridge Hospital, found that “touching, stroking or fondling were the most frequently reported type of molestation (60.5%)” in Singapore. No other known studies with local figures could be traced after this 1997 study.

Rubbing / molest is considered a “serious” crime in Singapore as it outrages the modesty of non-consenting individuals. Offences typically take place on overcrowded public transport or in places where there are heavy human traffic. The Mass Rapid Train (“MRT”) system in Singapore is notoriously overcrowded during peak hours, encouraging incidents of frotteurism. Buses which specify an unrealistic and uncomfortable (ie overcrowded) maximum passenger-carrying capacity, are also “popular” sites where frotteurs act out both blatantly and conveniently, as if such touching is perfectly normal and acceptable, taking advantage of the situational context of proximity to unsuspecting victims. Overcrowding makes it easier to disguise, avoid detection and escape. How not to get rubbed the wrong way when rubbing seems inevitable?

In order to achieve their purposes, frotteurs may present themselves to places eg MRT train platforms or on board trains during peak hours; Chinatown before Chinese New Year, or Little India during Deepavali where crowds would be expected. Often, they report succumbing to their urges when visually stimulated by the easy and “too-good-to-be-true” opportunities, without thinking about the consequences like apprehension, conviction and incarceration. The frequency of their acting out may reflect the severity of the disorder which could be both obsessive-compulsive and impulsive, rather than the degree of perversion and criminality.

SPF statistics noted an uptrend in Outrage of Modesty cases, which increased by 9.5%, to 717 cases in the first half of 2017, from 655 cases in the same period last year; with OM cases at entertainment night spots (52 cases) and on public transport (70 cases) being key concerns. There were news of steroids use in body-building which was associated with increased testosterone that allegedly led to sexual urges to touch.

Over the years, I have only assessed a handful of frotteurs with rubbing or touching behaviour, who were arrested, warned, prosecuted and incarcerated. The scanty number could be due to an ignorance of the condition, as well as the shame, secrecy and embarrassment surrounding the behaviour that stops offenders from seeking assessment and treatment. First-timers (ie arrested and charged for the first time) and repeat offenders were equally common. Mostly non-violent when they committed their crimes, they usually had a long history of undetected rubbing behaviour in crowded places or on public transport since their teens, and indulged in excessive and compulsive masturbation and use of pornography. Many of them did not know frotteuristic behaviour is a clinically diagnosable condition and that effective treatments are available.

Treatment of Frotteuristic Disorder

Without treatment, frotteurs tend to repeat their behaviour because of poor judgment and exceptional compulsion, and may become repeat offenders /serial rubbers.

The frotteurs I have assessed expressed that they have tried many, many times to stop their frotteuristic behaviours, by restraining or distracting themselves. They reported they were constantly preoccupied by the thoughts, and the urges to act out could be easily triggered when they placed themselves in a tempting, overcrowded setting. The release (ie orgasm) they achieved through their acts is reinforcing, leading to a vicious cycle of repetitive rubbing, which even overrides normal sexual intercourse. Frotteurs noticed the impulsive-compulsive nature of their frotteuristic activities as well as their compulsive masturbation. Despite knowing the undesirable and harmful legal consequences, they often operated on an “auto-pilot” mode and gave in to their urges, similar to behavioural addictions like gambling.

Both pharmacotherapy (medication that reduces impulsivity and sexual urges; selective serotonin reuptake inhibitors (‘SSRIs”) and androgen reduction therapy, eg gonadotropin-releasing hormone (GnRH] agonists) and psychotherapy (cognitive-behavioural therapy that targets erroneous beliefs, aversive conditioning, and covert sensitization) and group therapy have been found to be effective in treating Frotteuristic Disorder and Sexual Compulsivity. Equipping frotteurs with pro-social coping skills, emotional management, as well as developing new hobbies to distract them from excessive frotteuristic activities, are found to be effective in reducing their likelihood of reoffending. Enhancing victim empathy is also powerful in minimizing relapse. Comorbidities like depression, anxiety and other sexual paraphilias should be treated concurrently.

Punishment vs Rehabilitation

From time to time, I read about news of frotteurs being sentenced differently for their apparently quite similar crimes. I cannot help wondering about the sentencing discrepancies which may range from probation to a jail sentence of a few weeks to a few months. I noticed there were gaps when it comes to assessment and diagnoses, the frotteurs’ denial, and our lack of understanding, acknowledgement and acceptance of the condition. While having Frotteuristic Disorder is not a licence to rub/touch non-consenting individuals, the frotteurs should be afforded a thorough assessment and be rendered appropriate treatment (some were even willing to opt for a chemical castration to stop their struggles), in addition to a just sentence meted out for their crimes.

From my observation, there is much misunderstanding about the frotteuristic condition. Many old-fashioned psychiatrists and criminal justice personnel still consider compulsive rubbing behaviour a sexual paraphilia, ie a preference or a choice, and condemn those afflicted with Frotteuristic Disorder as “evil, perverse and immoral.” Individuals afflicted with the condition seldom have the opportunity to elaborate on their overpowering sexual urges during assessment, if there was one. They were deemed to have full control of their behaviour (e.g. “because they do not act out when standing next to police officers”). However, this apparent control is illusory as they easily give in to the rubbing urges when opportunities arise, despite the grave consequences of being apprehended.

Frotteuristic offenders who are convicted and incarcerated without receiving targeted treatment during their incarceration tend to repeat their behaviour upon their release from prison. Punishment alone does not remove the urge to rub, and it may not do the frotteurs justice. With appropriate treatment, most frotteurs are able to contain and modify their inappropriate behaviour. It is hoped that resources can be allocated to help them turn a new leaf and become useful members of society again.

Going Forward

Nowadays, videos and posters conveying the message “Don’t get rubbed the wrong way!” are shown and displayed on buses and in public places throughout Singapore. It is understandable that victims have every right not to be violated, and that frotteuristic acts may leave them feeling traumatized which require psychological treatment. Without minimizing the harm done to the victims, perpetrators of frotteuristic crimes when correctly diagnosed, are amendable to treatment and would significantly reduce their risk of re-offending. Installation of women-only passenger compartments on MRT trains can also minimize opportunities to commit opportunistic acts of frotteurism.


APA. (2013). Diagnostic and Statistical Manual of Mental Disorders. (5th ed.). American Psychiatric Association.

Bhatia S.N., Jhanjee A., Srivastava S., Kumar P. (2010). An uncommon case of hypersexual behaviour with frotteurism. Medicine, Science and the Law, 50, 228-229.

Chan, A.O., Lim, L.E. & Ong, S.H. (1997). A review of outrage of modesty offenders remanded in a state mental hospital. Medicine, Science, and the Law, 37(4), 349-352.

Grant J., Levine L., Kim D., Potenza M.N. (2005). Impulse control disorder in adult psychiatric inpatients. American Journal of Psychiatry. 162, 2184-2188.

Kalra G. (2013). The depressive façade in a case of compulsive sex behaviour with frottage. Indian Journal of Psychiatry. 55(2), 183-185

Krueger R.B. & Kaplan M.S. (2008). Frotteurism: assessment and treatment. In D.R. Laws & W.T. O’Donohue (Eds.), Sexual deviance: Theory, assessment, and treatment (pp. 150-163). New York: Guilford Press.

Lussier P. & Piche L. (2008). Frotteurism: psychopathology and theory. In D.R. Laws & W.T. O’Donohue (Eds.), Sexual deviance: Theory, assessment, and treatment (pp. 131-149). New York: Guilford Press.

Patra A.P., Bharadwaj B., Shaha K.K., Das S., Rayamane A.P. & Tripathi C.S. (2013). Impulsive frotteurism: a case report. Medicine, Science and the Law, 53(4), 235-238.

Consultant Forensic Psychologist
Forensic Psych Services
E-mail: [email protected]