Sibling abuse

Sibling abuse includes the physical, psychological, or sexual abuse of one sibling by another. More often than not, the younger sibling is abused by the older sibling.^[1][2] Sibling abuse is the most common of family violence in the US. Nationally-representative data show that about a third of US children, aged 0-17 years of age, have been victimized by their sibling in the past year.^[3] Sibling sexual abuse is estimated to occur for between 1-7% of siblings.^[4] Sibling abuse often goes unrecognized, even by those harmed by it.^[5][6][7] As opposed to sibling rivalry, sibling abuse is characterized by the use of control or power by one sibling over another.^[8][9] A power differential is not always easily identifiable,^[10][11] so an additionally important characteristic of sibling abuse is that the incidents or patterns of behaviors between siblings pose a high risk of serious physical and/or emotional harm and may include sexual coercion or violence.^[12] Sibling sexual abuse includes sexual behaviors that are unwanted, pressured, coerced, and may include contact or non-contact behaviors.^[13][14][15] Physical, psychological, and sexual abuse often co-occur.^[16]

Physical abuse

Sibling physical abuse can include shoving, hitting, slapping, kicking, biting, pinching, scratching, and hair-pulling. Sibling physical abuse is more common than peer bullying and other forms of family abuse, such as spousal or child abuse.^[12]

Even when sibling abuse is recognized it remains under-reported, due to the lack of recognition and resources provided to families, such as child protective services and mandatory reporters.^[17]

Sibling physical abuse can persist from childhood through adulthood, with prevalence rates varying across studies, though its frequency declines as the victim and/or sibling who harms age.^[2][3]

In Pakistani immigrant families in the UK, siblings have the highest proportion of physical abuse compared to other family members, with 35% being done by siblings, compared to 33% by mothers and 19% by fathers.^[18]

The findings for gender differences in sibling physical victimization experiences are mixed, but generally show that boys are more likely to be victimized than are girls.^[19][3] Additionally, age and birth order are also contributing factors to sibling abuse, where older siblings are more likely to abuse younger siblings.^[20]

Psychological abuse

Psychological abuse among siblings can be difficult to identify. Psychological abuse can include ridicule to express contempt, as well as degradation towards the other's self-esteem. Abusive psychological harm may involve extreme threats of harm or intimidation.^[3] Hence, the consequences of the aggression are not only injury, but also control or domination of one sibling over the other.^[2] Whipple and Finton^[21] report that "Psychological maltreatment between siblings is one of the most common, yet often under-recognized forms of child abuse." Being victimized by a sibling in childhood and adolescence causes fear.^[6]

Sexual abuse

Further information: Child-on-child sexual abuse

Sexual sibling abuse is defined as sexual behavior "that is not age appropriate, not transitory, and not motivated by developmentally appropriate curiosity."^[22] To identify sexual abuse, there needs to be coercion and domination over one sibling, although the power differential between siblings can sometimes be subtle and hard to discern, especially when siblings are close in age.^[23] Prevalence rates are also difficult to calculate for several reasons: victims often do not realize that they are suffering abuse, until they reach maturity and have a better understanding of the role they played during the encounters, they are afraid of reporting, and there is no consensus on a definition of sibling sexual abuse.^[11] A nationally representative survey of adults in Australia found that 2% had experienced sibling sexual abuse in childhood.^[24]

As with other forms of abuse among siblings, there is a lack of reporting in sibling sexual abuse, as parents either do not recognize it as being abuse or try to cover the abuse.^[11][25] An increased risk of sibling sexual abuse may be found in a heightened sexual climate in a family, or in a rigidly, sexually repressed family environments.^[22][23][11] Sexual abuse in siblings may have long-term effects on the victims. Many victims have been diagnosed with a variety of psychological problems.^[26] Victims have been reported to correlate pain and fear with sex, leading to long-term issues with intimacy.^[27]

Rudd and Herzberger^[27] report that brothers who committed incest were more likely to use force than fathers who commit incest (64% vs. 53%). Similarly, Cyr and colleagues^[20] found that about 70% of sibling incest involved sexual penetration, substantially higher than other forms of incest. Rayment and Owen^[26] report that "[in comparison of] the offending patterns of sibling offenders with other teenage sex offenders ... Sibling abusers admitted to more sexual offenses, had a higher recidivism rate, and a majority engaged in more intrusive sexual behaviour than other adolescent sex offenders. The sibling perpetrator has more access to the victim and exists within a structure of silence and guilt." Research has also shown that compared to adolescents who sexually harm non-siblings, adolescents who sexually harm siblings have experienced more adverse childhood experiences^[28] and are more likely to have a history of being sexually abuse themselves.^[29]

Identification

Common parental reactions include minimization of the harmful impact of sibling aggression,^[30] expression of disbelief, or making of excuses for the behaviors.^[31] Many professionals, such as those in child protective services, law enforcement, school counselors, pediatricians, and nurses, may not know that sibling aggression and abuse happen, are not trained to ask about it, and do not have knowledge of how to respond.^[6][32] Screening questions about types of aggression, frequency, the intention of harm, the magnitude of the aggression, and unidirectional dominance help assess the existence of abuse.^[1][2]

Weihe^[1] has four criteria that is used to determine if questionable behavior is rivalry or abusive. First, one must determine if the questionable behavior is age-appropriate, since children use different conflict-resolution tactics at various developmental stages. Second, one must determine if the behavior is an isolated incident or part of an enduring pattern: abuse is, by definition, a long-term pattern rather than occasional disagreements. Third, one must determine if there is an "aspect of victimization" to the behavior: rivalry tends to be incident-specific, reciprocal, and obvious to others, while abuse is characterized by secrecy and an imbalance of power. Fourth, one must determine the goal of the questionable behavior: the goal of abuse tends to be embarrassment or domination of the victim.

A challenge to identifying sibling sexual abuse is differentiating between sexual abuse and developmentally-appropriate sexual behavior.^[1][33] A victim may not be aware that he/she did not consent because of innocence or lack of understanding of what was happening.^[33] The latter generally happens to children who are too young to understand sexual implications and boundaries.

Risk factors

There are several important risk factors associated with sibling abuse.^[2] They can be categorized into family system, parenting behavior, individual, and other risk factors.^[2]

Family system

This category of risk factors associated with sibling abuse looks at the family system as a whole. It includes negative and conflictual parent-child relationships,^[34] parental hostility toward a child, spousal abuse,^[34] partner conflict, marital conflict,^[34] financial stress,^[35][2] low family cohesion, family disorganization and household chaos,^[2][22] parental alcoholism,^[2][36] parental support of child aggression,^[30] low maternal education, family adversity,^[37][38] and family triangulation.^[2][39]

Parenting behavior

This category of risk factors associated with sibling abuse examines the parenting behavior of adult caregivers. It includes parental differential treatment of children, parents labeling their children "bad-good" and "easy-difficult",^[2] low parental involvement,^[2] ineffective parenting, inconsistent discipline,^[34] coercive parenting,^[2] parental abuse of children,^[2][34] parental neglect and approval of aggression,^[2][30] corporal punishment,^[36] not providing supervision,^[34] not intervening in sibling conflict,^[2] not acknowledging child-voiced claims of maltreatment.^[1]

Individual

This category of risk factors associated with sibling abuse considers individual traits of the harming child and the victim child. For children who harm their siblings, known individual risk factors include lack of empathy for victims,^[2][22] unmet personal needs for physical contact in emotion-deprived environments,^[22][23][2] experience of victimization, including by siblings, sibling caretaking of younger brothers and sisters.^[22][36][40]

Children harmed by siblings, children with autism or physical disabilities are at a greater risk of being victimized by their sibling than are typically developing children.^[41][42] Siblings who are LGBQ are at risk for sibling victimization.^[43]

Potential effects

The effects of sibling abuse closely parallel those of other forms of child abuse.^[6] Consistent evidence demonstrates that harming a sibling or being victimized by one is associated with negative impacts on mental and physical health across the lifespan.^[44][31][45] Sibling aggressive and abusive behaviors are associated with depression, anxiety, and low self-esteem in childhood and adulthood.^[46][47] It is possible that there may be significant problems following sibling abuse such as affect regulation and accompanying affect disorders, impulse control, somatization, post-traumatic stress disorder, eating disorders such as anorexia or bulimia nervosa, substance abuse issues, major depression and problems with socialization.^[1] Sibling abuse is associate with other behavior problems such as aggression and delinquency.^[48]

Research has repeatedly shown that sibling aggression sets the stage for peer aggression.^[19][49] 15% of children and adolescents victimized at home by a sibling are also victimized at school by peers.^[7] A school bully may be harmed by a sibling at home. It also sets the stage for dating violence.^[50]

In addition to the above impacts of sibling abuse more generally, potential effects of sibling sexual abuse include difficulty separating pleasure from pain and fear from desire in a sexual relationship, re-victimization in adulthood, difficulty in developing and sustaining intimate relationships, trouble negotiating boundaries, intimacy issues, and interdependency in relationships.^[31][27][25]

Siblicide may be an effect of sibling abuse in which a sibling commits homicide against another sibling; typically seen as a male sibling entering life as an adult against a younger brother.^[51]

Caffaro and Conn-Caffaro report, based on their research, that adult sibling abuse survivors have much higher rates of emotional cutoff (34%) with brothers and sisters than what is evident in the general population (<6%).^[8]

Media portrayals

An important plot point within the traditional fairy tale of Cinderella is the eponymous main character's cruel treatment at the hands of her stepsisters with their mother's implicit approval.

The 1991 made-for-TV movie My Son, Johnny is a rare fictionalized portrayal of sibling abuse. The film stars Corin Nemec as a teenager victimized by his older brother, played by Rick Schroder. The film was inspired by the real-life case of Philadelphia fifteen-year-old Michael Lombardo, tried and acquitted for the 1985 killing of his nineteen-year-old brother, Francis "Frankie" Lombardo, who had battered and abused him for years.

British soap opera Hollyoaks ran a storyline in 2024 featuring sibling sexual abuse between twins Jack Junior (JJ) and Frankie Osborne.^[52] The portrayal highlighted family dynamics, including parental favoritism of JJ as the “golden boy” and the abuse’s negative impacts on Frankie, who began binge drinking and self-harming.^[53] The Hollyoaks production team consulted with experts from SARSAS to ensure a realistic portrayal of sibling sexual abuse.

Notable examples

Cheyenne Brando, the daughter of the legendary actor Marlon Brando, confessed that her brother Christian seemed to be in love with her, and that he was jealous of her boyfriend Dag Drollet; that is why Christian killed him in 1990, according to Cheyenne. Christian stated during his trial that Cheyenne told him that Dag was abusive to her, and that he wanted to protect her, and that he never meant to kill Dag; it was a "terrible accident." Christian was sentenced to ten years in jail in 1991, and Cheyenne committed suicide in 1995. Cheyenne was abusive toward her two sisters, Maimiti and Raiatua, as well as towards Marlon Brando and Tarita, her parents, particularly her mother. Tarita Teriipaia wrote a book in 2005, which revealed Cheyenne terrorized her own family, as a result of her suffering from schizophrenia.

The French serial killer Guy Georges physically abused his adoptive elder sisters when he was 14, nearly killing them.

In 2013, the Australian actor Hugh Jackman opened up about the physical and verbal abuse by his older brother. He said the abuse helped his acting in Wolverine, and that when his brother apologized, Jackman felt released.

The 2013 documentary Sibling Rivalry: Near, Dear and Dangerous highlighted the aggressive and abusive sibling relationships of several notable figures, including actresses Olivia de Havilland and Joan Fontaine.