Sibling Aggression and Abuse: Invisible and Widespread Public Health Problems

Sibling aggression and abuse are largely overlooked public health problems. The invisibility of these harmful sibling dynamics is partly driven by the tendency to mislabel such behaviors as rivalry, which is considered temporary and harmless. As such, the nature and impact of these behaviors and public attention to them are minimized or dismissed.^1,2 This perception, along with the shame and stigma associated with incidents of family violence, has made addressing this public health issue challenging.

Visibility is needed, however, because sibling aggression and abuse are the most common forms of family violence³ and are consistently associated with mental and physical health problems and familial and extrafamilial relationship difficulties in adolescence.^4,5 Screenings and evidence-based interventions aimed at identifying and responding to sibling aggression and abuse can improve the adolescent population’s health, relationship functioning, and social skills such as emotion regulation and conflict management and resolution; they can also have a positive impact on society’s functioning.

Sibling aggression and abuse are prevalent in the United States and are more common than caregiver neglect and abuse or peer assault.³ Sibling aggression, one-sided or mutual competition for or protests about caregivers’ attention or favor,⁶ is different from rivalry, although in extreme cases rivalry can lead to aggressive behavior. The definition of sibling aggression includes minor and severe physical assault (without or with an injury or use of a weapon), psychological aggression (e.g., threats, belittling, isolation), and property violence (e.g., forcibly taking or damaging personal items). The extent of the emotional and physical impact of such behaviors on the harmed sibling is related to their severity.²

US Census Bureau data show that approximately 80% of US children have siblings.⁷ The only US nationally representative study of harmful sibling dynamics showed that they are a frequent occurrence: 37.6% of children one month to 17 years of age who lived with a sibling were victimized in the past year by their sibling in one or more incidents of physical, psychological, or property aggression.⁸ This study also revealed sociodemographic variations in frequency: relative to their counterparts, sibling victimization is more commonly reported by White children, boys, and children whose parents have some college education. Although sibling victimization peaks in childhood at 46.1%, 35.7% and 27.6% of adolescents 10 to 13 and 14 to 17 years of age, respectively, were victimized by a sibling in the past year. The most commonly reported form of sibling victimization was physical assault (31.4% among adolescents 10–13 years old and 23.1% among adolescents 14–17 years old).

Many incidents of sibling victimization are minor, but some are severe or abusive. Although both aggressive and abusive sibling behaviors cause harm and should be prevented and stopped, sibling abuse is distinguished by one sibling demonstrating power and control over the other on the basis of age, gender, physical size, cognitive ability, or parental favoritism.^1,5 Sibling abuse is characterized by a single incident or repetition of behaviors that include a high risk of serious physical or emotional harm to a sibling.^1,9

Notably, 4.9% of adolescents 10 to 13 years of age and 6.9% of adolescents 14 to 17 years of age in the study just described reported that the incidents of sibling victimization they experienced included an injury or a weapon.⁸ In another study, 62% of adolescents who experienced sibling victimization that included injury or use of a weapon reported being afraid of their sibling, and this finding was consistent according to gender, ethnicity, and level of parental education.² Adolescent sibling aggression and abuse co-occur with many family problems, including intimate partner violence, child maltreatment, problematic parenting, and adverse events such as job loss, divorce, and family illness.^4,10 This may reflect a family atmosphere of poor emotion regulation and violence. Unfortunately, these family difficulties often take precedence over adolescent sibling aggression and abuse, leaving victims ignored and, in some cases, poly-victimized.

In light of this research, it is clear that to adequately address adolescents’ mental health needs, a public health approach is needed to identify and respond to sibling aggression and abuse. Public health practitioners are likely aware that, as with survivors of other forms of family violence, adolescents and their parents may not be comfortable identifying harmful sibling behaviors as abuse. Furthermore, practitioners generally receive little or no training on sibling aggression and abuse.¹¹ However, given the importance of sibling relationships to adolescents’ mental health and the prevalence of sibling aggression and abuse, identification of these incidents and destigmatization of this form of family violence are paramount to enhance the adolescent population’s health. One study showed that even a single harmful sibling incident in the past year is associated with mental health distress.¹² Reducing the prevalence of sibling aggression and abuse could lower incidents of family violence, increase help seeking, and have a positive societal impact on adolescents’ mental health.

DIRECT IMPACTS ON ADOLESCENT MENTAL HEALTH

The unique characteristics of sibling relationships, including frequent contact and emotional intensity, make them especially salient for adolescent mental health.⁶ Whereas sibling warmth and support are positively associated with well-being, sibling aggression and abuse are linked to a variety of mental health challenges in adolescence, including distress,^5,12 depression,¹³ low self-esteem,¹³ anxiety,¹⁴ and psychotic disorders.¹⁵ Sibling victimization, especially when it is chronic or severe, can cause fear and lead an adolescent to feel unsafe at home.² The negative effects of sibling aggression and abuse on mental health are independent of the impacts of co-occurring family problems such as parental child maltreatment and witnessing of family violence.^12,14,15 Most research has focused on mental health associations with sibling victimization, but there is also evidence that sibling aggressors experience mental health challenges.¹⁵

Importantly, research incorporating longitudinal data shows that whether sibling victimization increases, decreases, or persists over time is also linked to adolescent mental health. In one study, chronic sibling victimization that persisted across two time points was linked to more severe forms of victimization and greater mental health distress in adolescence.⁵ Another study showed that adolescents who reported decreasing sibling victimization from age 11 years to age 14 years had levels of depressive symptoms, life satisfaction, and self-esteem similar to those of adolescents who reported consistently low levels of sibling victimization.¹³ This line of research suggests that taking a public health approach to prevention and intervention programs aimed at reducing sibling aggression and abuse could lead to improvements in mental health for large numbers of adolescents.

Harmful sibling dynamics and their associated effects in adolescence can persist into adulthood. Some of the challenges reported by adult survivors include depression, anxiety, low self-esteem, eating disorders, posttraumatic stress disorder, and difficulty forming close and trusting relationships with others.¹ Far from being a temporary annoyance, aggressive and abusive sibling dynamics in adolescence can lead to lasting harm and likely have a significant impact on the adult population’s mental health.

INDIRECT IMPACTS ON ADOLESCENT MENTAL HEALTH

In addition to direct impacts of sibling aggression and abuse on adolescent mental health, there are indirect pathways through which sibling aggression likely affects mental health. One pathway is its connection to other forms of peer aggression, including dating violence and bullying, both of which have known links to mental health challenges in adolescence.^16,17 Involvement in sibling aggression, especially as the aggressor, is associated with the occurrence of dating violence.¹⁸

In addition, there is a consistent positive association between sibling aggression and being the aggressor in or victim of peer bullying.^19,20 A longitudinal analysis of US nationally representative data revealed that chronic sibling victimization more than doubled the risk of peer victimization.²⁰ Sibling aggressors also have an increased likelihood of being involved in peer bullying as victims, aggressors, or both.¹⁹ At least one study has linked sibling victimization to cyberbullying victimization.²¹

This accumulated evidence suggests that, through social learning processes, aggression learned in sibling relationships can spill over into other relationships. Thus, reducing sibling aggression could lead to decreases in significant societal problems such as peer bullying and dating violence and consequently improve the adolescent population’s mental health.

The lack of parental validation and support experienced by many young people victimized by their siblings is another possible indirect pathway from sibling aggression and abuse to adolescent mental health challenges. Common parental responses, even to more severe forms of sibling abuse, include minimizing, ignoring, and blaming the victim.²² These invalidating responses may come about from parents unfairly favoring the harming sibling while simultaneously labeling the disfavored harmed child as having problematic qualities (e.g., a difficult personality). These responses can happen when sibling victimization co-occurs with parental child maltreatment, or they can reflect the broader cultural invisibility of sibling aggression and abuse. When adolescents’ experiences of sibling victimization are accompanied by the apparent unwillingness or inability of their parents to protect and support them, this represents additional victimization and can amplify their feelings of worthlessness, hopelessness, and despair.¹

The COVID-19 pandemic and lockdown may also have exacerbated adolescent mental health challenges through sibling aggression and abuse. One study revealed a higher prevalence of sibling aggression and abuse during the pandemic than before the pandemic.²³ Another showed that children and adolescents with special educational needs and disabilities were more likely to be victims of sibling aggression and abuse as the COVID-19 lockdown progressed than when it began.²⁴ The negative effects of the COVID-19 pandemic and lockdown on adolescent mental health have been well documented,²⁵ and sibling aggression and abuse likely served as a connecting variable between COVID-19 and adolescent mental health challenges. Furthermore, it is likely that during the pandemic, adolescent aggressors in and victims of sibling aggression and abuse experienced mental health challenges, thereby potentially perpetuating a recursive cycle of such behaviors.

ADVERSE CHILDHOOD EXPERIENCES

Public health practitioners often use an adverse childhood experience (ACE) inventory to assess trauma and decisions about care. ACEs represent a list of experiences such as abuse, neglect, violence, and household dysfunction occurring before the age of 18 years that have a cumulative impact on mental and physical health over the life span and lead to significant public health costs. An ACE can be a single incident or occur over an extended period, leading to chronic stress and inflammation. Traditional ACE inventories have not explicitly included sibling aggression and abuse, missing an important source of trauma among adolescents. Given the pervasive mislabeling of sibling aggression as rivalry and a lack of practitioner training, this source of trauma is likely missed without explicit screening for harmful sibling experiences, thus limiting responsive approaches to adolescent mental health. Multiple scholars have called for sibling aggression and abuse to be considered ACEs to enhance the identification of this form of trauma and the development of innovative response strategies.^5,11

Notably, sibling aggression and abuse have associations with mental health that are similar to (and sometimes larger than) associations involving traditional ACEs, including child maltreatment, sexual victimization, and witnessing of family and community violence.¹² Incidents of adolescent sibling aggression and abuse are stressful and can be trauma inducing, particularly for harmed siblings, depleting their emotional and physical resources and creating vulnerability to a range of health issues. In addition, for some adolescents, sibling aggression and abuse can be chronic and persistent.⁵

To help alleviate the public health costs of adolescents’ trauma and chronic stress from exposure to sibling aggression and abuse, ACE inventories should be broadened to include sibling aggression and abuse explicitly. With greater awareness and recognition, sibling aggression and abuse are likely to be prioritized and considered part of comprehensive support for adolescents’ mental health and their experiences with all forms of family violence. As with any ACE, however, it will be critical to develop evidence-based responses to healing the trauma of sibling aggression and abuse.

IMPLICATIONS FOR PRACTITIONERS

When sibling aggression and abuse are conceptualized as public health concerns, the need for practitioner involvement in preventing and intervening in instances of sibling aggression and abuse to address adolescents’ mental health is readily apparent. On the basis of findings from their research on the association between sibling aggression and child and adolescent mental health, Tucker et al. noted that “the public should treat sibling aggression as potentially harmful and something not to be dismissed as normal, minor, or even beneficial.”^12(p84)

It is time for public health initiatives to address sibling aggression and abuse to prevent this form of family violence and improve adolescent mental health. A social awareness campaign aimed at a range of providers in different disciplines could be enacted to distinguish sibling rivalry from aggression and abuse and appropriately label the latter behaviors as family violence. Public health practitioners also need to receive training on identifying and responding to sibling aggression and abuse so that these behaviors are no longer overlooked. Currently, few organizations offer such training (an exception is the Sibling Aggression and Abuse Research and Advocacy Initiative), and the topic is generally absent from undergraduate and graduate curricula and continuing education requirements. Thus, expanding the capacity to offer education and training is essential and will have a positive societal impact.

Despite efforts to call sibling aggression and abuse an issue warranting consideration in family and public health,^1,5 prevention and intervention strategies remain scarce, and sibling aggression and abuse are rarely perceived as encompassed within family violence. Developing evidence-based strategies to create a shared understanding of and accessible approaches to communication and conflict management should be prioritized. These strategies could then be infused into existing parent education, antibullying, and dating violence programs to strengthen adolescent mental health. Furthermore, public health practitioners should consider expanding the focus of mental health and social services agencies, hospitals, and community centers to include sibling aggression and abuse.¹ This endeavor could begin with screening for sibling aggression and abuse as part of ACE inventories. Public health practitioners are likely to be first responders to incidents in which adolescents are harmed by siblings, thus giving them the unique opportunity to provide parent education and, if needed, a referral for abuse.

CONCLUSION

Given the prevalence of sibling aggression and abuse and their connections to mental health challenges in adolescence, efforts toward public education, interventions, and policy regarding sibling aggression and abuse are not only warranted but necessary for addressing this pervasive form of family violence that affects the adolescent population’s mental health. With greater awareness, training, and evidence-based responses, societal perceptions that keep sibling aggression and abuse hidden will evolve with benefits for adolescents, their mental health, and their familial and extrafamilial relationships.