Sibling adjustment to diabetes and educational needs: A literature review.

ABSTRACT: As cases of type 1 diabetes mellitus (T1DM) increase, so do their impact on sibling relationships. This literature review of four databases from 2010 to 2024 discusses findings from five studies and the themes that emerged: education needs and family functioning. Improvements in family-centered care and education are needed for siblings of children with T1DM.

Using emulated clinical trials to investigate the risk of being diagnosed with psychiatric ill health following the cancer diagnosis of a sibling.

BACKGROUND: The sibling bond is often the longest relationship in an individual's life, spanning both good and bad times. Focusing on the latter, we investigated whether a cancer diagnosis in one adult sibling is predictive of psychiatric illness in the other, and if any such effect differs according the 'sociodemographic closeness' between the siblings in terms of sex, age, education, marital status and residence. METHODS: We used hospital records to identify psychiatric diagnoses (2005-2019) in a Swedish total-population cohort born in 1953, and cancer diagnoses (2005-2017) in their full siblings. By means of emulated clinical trials, the cohort member's risk of a diagnosis within two years following a first exposure (or non-exposure) to a sibling's cancer was analyzed through Cox regression. RESULTS: Exposed cohort members had a higher risk of psychiatric diagnosis than unexposed (HR = 1.15; CI: 1.08-1.23), with men displaying a higher risk (1.19; CI: 1.09-1.31) than women (HR = 1.11; CI: 1.01-1.22). Sub-analyses of the exposed group showed that women with a cancer-stricken sister had a higher risk of adverse psychiatric outcomes (HR = 1.31; CI: 1.07-1.61) than women with a cancer-stricken brother. Furthermore, unmarried cohort members ran a higher risk, both when the cancer-stricken sibling was married (HR = 2.03; CI: 1.67-2.46) and unmarried (HR = 2.61; CI: 2.16-3.15), than in cases where both siblings were married. No corresponding difference were detected for 'closeness' in age, education and residence. CONCLUSIONS: In line with theories of linked lives, our findings suggest that negative events in one sibling's life tend to 'spill over' on the other sibling's wellbeing, at least during the 15-year-long period leading up to retirement age.

Sibling comparisons, sibling relationship quality, and perceived sport competence in young athletes.

Siblings are overlooked, yet potentially meaningful social agents in youth sport. To better understand the role of siblings in youth sport, we examined the association between sibling sport-referenced comparisons, relationship qualities, and perceived sport competence. The tendency to make sibling comparisons was expected to be positively related to sport competence perceptions and this association was further expected to be moderated by markers of sibling relationship quality. Participants were 47 sport-involved sibling dyads that included older siblings (25 female, 22 male, Mage = 10.94 ± 1.49 yrs) who were predominately first-born children (83%) and their younger siblings (23 female, 24 male participants, Mage = 8.45 ± 1.01 yrs) who were mostly second-born children (79%). Participants completed established assessments of comparison tendency, sibling relationship qualities, and sport competence perceptions. Analyses revealed a three-way interaction between birth position (younger or older sibling), tendency to compare, and sibling warmth predicting sport competence (p < .05). Younger siblings with a greater tendency to make sibling comparisons and higher warmth perceptions reported higher sport competence perceptions. The findings suggest that sibling-based comparisons and relational warmth may be salient for younger siblings in gauging their competence, whereas older siblings utilize alternative sources of competence information.

'People don't realise how much their past experiences affect them in adulthood': A qualitative study of adult siblings' experiences of growing-up with a sister/brother with a childhood life-limiting condition and their perceived support needs.

BACKGROUND: There is a lack of research about the experiences and impact of having a sibling with a life-limiting condition. Studies focus on the sibling experience during childhood but the experience and impact during adulthood is unknown despite the increased life-expectancy of children with life-limiting conditions. AIM: To explore adult siblings' perspectives on the experience of having a sister/brother with a childhood life-limiting condition and to identify their perceived needs and preferences for support. DESIGN: A qualitative exploratory study design with data generated by semi-structured interviews and analysed using reflexive thematic analysis, underpinned by interpretivism. SETTING/PARTICIPANTS: Twenty-two siblings (17-42 years old) were recruited via a children's hospice in England. RESULTS: The experience of having a sibling with a life-limiting condition changes over time in response to how understandings of the meaning of a life-limiting condition develop and changing roles/relationships with parents and siblings. These experiences have an enduring impact on adult sibling's mental health which is compounded by their unmet (and sometimes unrecognised) support needs in adolescence and adulthood. Siblings described the importance of support continuing into adulthood with a focus on the provision of psychotherapy and peer support. CONCLUSIONS: Having a sister/brother with a childhood life-limiting condition appeared to have a significant and ongoing impact on adult siblings but their support needs, particularly for psychotherapy and peer support, are overlooked. The findings highlight the importance of ensuring siblings are included in family assessments and that family-based interventions are developed to promote sibling-parent relationships.

What challenges do siblings of children with chronic disorders express to their parents? A thematic analysis of 73 sibling-parent dialogues.

PURPOSE: The study explored challenges experienced by siblings of children with chronic disorders, as expressed by siblings in parent-child dialogues. DESIGN AND METHODS: Seventy-three parent-child dialogues (M duration = 28.6 min) were analyzed using qualitative thematic analysis. The dialogues took place within the SIBS group intervention for siblings and parents of children with chronic disorders. The siblings (aged 8 to 14 years) had brothers and sisters with autism spectrum disorders, ADHD, rare disorders, cerebral palsy, or severe mental health disorders. The data are from session 5 in the SIBS intervention, in which the siblings are to express their wishes about family-related challenges (e.g., desired changes) to their parents. The parents are encouraged to listen, explore, and validate the child's perspective before discussing solutions. RESULTS: Most of the family-oriented challenges the siblings expressed were related to the diagnosis of the brother or sister with a disorder. Four main themes were identified: (1) Family life (e.g., limitations in family activities); (2) The diagnosis (e.g., concerns about the future); (3) Violence; and (4) Important relationships. CONCLUSION: The siblings experienced challenges and difficult emotions in interactional processes in which the diagnosis affected family life and relationships. The study adds a new dimension to the field by identifying siblings' expressed challenges based on parent-child dialogues. PRACTICE IMPLICATIONS: Identified themes can guide how parents should meet and address siblings' needs, how health care providers inform and support parents in doing so, and emphasize the relevance of interventions targeting family-level risk and resilience factors.

'No one else understands', 'I wouldn't want to pity myself over something that's not really my problem': siblings' experiences of their adolescent brothers and sisters' inpatient treatment for mental health difficulties.

BACKGROUND: Family life is disrupted when a child experiences mental health difficulties. This can have long-standing effects on sibling relationships. This study explores the lived experiences of young people who have an adolescent sibling hospitalised for treatment of a mental health difficulty. METHOD: Semi-structured interviews of 45-60 min were conducted to explore the experiences of 10 siblings (6 sisters/4 brothers aged 13-22) of nine patients (5 sisters/4 brothers aged 15-17) receiving treatment for a mental health difficulty in a child and adolescent inpatient unit (IPU). Interpretative phenomenological analysis was used to analyse the data. RESULTS: Two superordinate themes were identified: 'Who am I if I'm not supporting them?' and 'On the fringes: actively involved but from the outside'. The interplay of these two super-ordinate themes was found to influence the five sub-ordinate themes: 'Confusion and disbelief', 'Don't worry about me, focus on them.', 'Powerless when I need to be powerful.', 'Helping or hindering- what is this place??' and 'Knowledge is power.' CONCLUSION: Siblings described experiencing conflicting and confusing emotions which may impact their attendance in IPU and engagement in siblings' treatment. Siblings of adolescents in inpatient treatment for mental health difficulties may be at increased risk of experiencing psychological distress. The mental well-being of siblings must be borne in mind by child and adolescent inpatient services supporting families in crisis.

Observation of Early Social Interactions in Sibling Dyads: A Systematic Review.

Sibling relationships provide unique social experiences that can vary across the lifespan. Early sibling social interactions (ESSI) have been associated with children's own relationship and developmental outcomes, highlighting the essential role that sibling encounters play, even from a young age. Understanding how these social exchanges occur and unfold and the range of opportunities they provide can shed light on critical aspects of early childhood development and family life. However, the methodological approach used in studying ESSI can influence our understanding of these early experiences. This systematic review aims to delineate the methodological framework adopted in observational studies of ESSI. Through a systematic search of psychology and domain-general databases until March 2023, we focused on studies that addressed bidirectional naturalistic interactions in young sibling dyads (at least one child aged 0-36 months). Of the 713 articles screened, only 63 met the inclusion criteria. Findings regarding three main issues are examined, including sample characteristics, study designs and procedures, and sibling interactive behaviours targeted. Previous research has focused on a diverse range of sibling behavioral exchanges, including cues of children's social skills and relationship quality within mainly ecological contexts. However, limitations in representativeness and standardization have been identified. Future studies should incorporate sequential analyses to fully comprehend the interactive nature of early sibling social encounters.

The experiences of having a sibling with an eating disorder: A systematic review of the literature.

OBJECTIVE: Research on carers in the context of eating disorders (EDs) has predominantly focused on parents and offspring, overlooking the adverse effects EDs have on the lives of siblings. This study aims to shift the paradigm by reviewing the literature in this area. To the authors' knowledge, this is the first review of the literature that broadly captured the lived experiences of siblings without being limited by specific search terms such as coping strategies and levels of psychopathology. METHOD: Six databases (ERIC, MEDLINE, PsycInfo, Pubmed, Scopus, and Web of Science) were searched using predetermined search strings. Quantitative, qualitative, and mixed methods studies were included as long as they were focused on siblings' experiences of having a brother or sister with an ED. No publication date restrictions were applied, and thorough quality assessments were initially carried out before a qualitative analysis of the data was conducted. RESULTS: Twenty-one studies were eligible for inclusion, thematic synthesis yielded six core themes, and 17 subthemes related to the inter- and intrapersonal impacts of the ED on siblings' lives. These themes and sub-themes include fragmentation in family relationships, parentification, and competition and jealousy. CONCLUSION: It is of utmost importance to gain a better understanding of siblings' experiences and needs in relation to EDs. The findings are discussed in relation to the existing literature and theoretical and clinical implications, for example, tailored approaches accounting for siblings' experiences.

Sibling effects on problem and prosocial behavior in childhood: Patterns of intrafamilial "contagion" by birth order.

We investigated longitudinal relations between siblings' problem and prosocial behavior, measured by the Strengths and Difficulties Questionnaire, among different sibship sizes in the UK's Millennium Cohort Study. We identified 3436 families with two children and 1188 families with three children. All children (cohort members and their older sibling [OS]) had valid data on behavior at two time points (in 2004 and 2006). Using structural equation model, we found that for internalizing and externalizing problems, OSs (MOS1 = 6.3 years, MOS2 = 9.1 years at T1) exerted a dominant effect on younger siblings (Mage = 3.12 years at T1; 49.7% boys) across sibship sizes. For prosocial behavior, there was OS dominance in two-child families and youngest sibling dominance in three-child families.

Sibling Relationship and Behavioral Adjustment in Families of Disabled Children: Cross-Lagged Associations.

Cross-lagged panel designs were used to examine longitudinal and potential (bi)directional relationships between primary caregiver reported sibling relationship quality and the behaviors of children with intellectual disability (n = 297) and their closest in age siblings. The behavioral and emotional problems of the child with intellectual disability positively predicted sibling conflict over time. When accounting for control variables, this relationship was no longer present. Sibling warmth positively predicted the prosocial behaviors of the child with intellectual disability over time. When accounting for control variables, both sibling warmth and sibling conflict positively predicted the prosocial behaviors of the child with intellectual disability over time. Future research directions and clinical implications are discussed.

Short report: Siblings of children with neurodevelopmental disorders, a phenomenological perspective on parental perception.

BACKGROUND: Siblings, typically developing brothers and sisters of children with neurodevelopmental disorders (NDD), are at risk for long-term psychosocial difficulties. OBJECTIVE: The present study aims at obtaining an in-depth insight on the lived experience of siblings of children with NDD through their parents' perspective. METHODS: Seven mothers and three fathers who signed up their sibling children (12-15 years) to a peer-support intervention participated in a semi-structured videoconference interview according to the Interpretative Phenomenological Analysis (IPA) qualitative approach. Interviews were conducted by trained personnel and independently coded. RESULTS: Thematic analysis highlighted three core themes and twelve sub-themes: "The complexity of the fraternal relationship" (three sub-themes), "Growing up with diversity" (six sub-themes), and "Me as a sibling" (three sub-themes). CONCLUSIONS: The study provides insight on parents' perception of the lived experience of their sibling children, thus spreading awareness on the everyday difficulties families with a child with NDD may encounter. WHAT THIS PAPER ADDS: The present study contributes to the scarce literature on the lived experience of siblings of children with NDD, and notably it is one of the few qualitative studies on the topic which makes use of an IPA interviewing style. This methodological choice allowed for an in-depth understanding of siblings' strengths and struggles as perceived by their own parents, and of how their brother/sister's condition impacted on their family role, socio-emotional development and personality. Recounting siblings' experiences contributes in spreading awareness on the everyday difficulties siblings and their families face when cohabitating with a child with NDD.

Understanding sibling violence and its impact over the life course: The case of Ghana.

Sibling relationships are a significant part of family dynamics, and sibling violence may be manifested in these relationships. Sibling violence has rarely been examined in the domestic violence literature on sub-Saharan Africa, so little is known about its prevalence or consequences. This study used a life course perspective to examine the effects of sibling violence on Ghanaian women's intimate partner violence (IPV) victimization and perpetration in adulthood. Data were collected from about 1700 ever-married Ghanaian women aged 18 years and above between May and August 2022. Logit models were used to explore retrospective accounts of women's experience of various types of sibling violence in childhood and their later victimization and/or perpetration of IPV. Results showed sibling violence was prevalent in our sample: 51.2% experienced sibling emotional violence, 39.5% experienced physical violence, and 2.3% experienced sexual violence. Our findings generally supported the life course perspective. Women with experiences of sibling physical, sexual, and emotional violence were significantly more likely to perpetrate physical, sexual, and emotional IPV in adulthood. Similarly, women with experiences of sibling violence were more likely to report IPV victimization in later years. Domestic violence interventions should pay attention to sibling relationships in children's early years.

Influence of hearing loss on sibling relationships: Perspectives of the normal hearing sibling.

BACKGROUND: Sibling relationships, one of the most extended relationships in life, contribute to an individual's social and emotional development. However, this relationship may be influenced if one sibling has a hearing loss. OBJECTIVES: This study explored the influence of a hearing loss on the sibling relationship by gaining the perspectives of the sibling with normal hearing. METHOD: Adopting a phenomenological research design, semi-structured online interviews were conducted using Zoom and WhatsApp with nine participants who have siblings with hearing loss. RESULTS: Hearing loss may significantly impact the normal hearing sibling's quality of life, affecting their psychological and social well-being, familial and peer relationships and overall experiences. Personal development, independence, maturity and closer sibling bonds were some of the positive influences reported by the participants. Attendance to aural rehabilitation therapy sessions, knowledge of hearing loss, personalities and household living arrangements positively influenced the relationship between siblings. The lack of attendance to aural rehabilitation sessions resulted in communication difficulties between siblings. CONCLUSION: There is a need to include siblings in aural rehabilitation and family engagements related to the child with hearing loss to provide a holistic and more effective rehabilitation and adjustment process.Contribution: This study aimed to improve family-centred intervention as it is focussing on the siblings' perspectives of the hearing loss. Furthermore, previous studies have generally focussed on adults and not much research has been conducted surrounding the sibling relationship.

Donor sibling relations among adult offspring conceived via insemination by lesbian parents.

STUDY QUESTION: How do adult offspring in planned lesbian-parent families feel about and relate to their donor (half) sibling(s) (DS)? SUMMARY ANSWER: A majority of offspring had found DS and maintained good ongoing relationships, and all offspring (regardless of whether a DS had been identified) were satisfied with their knowledge of and contact level with the DS. WHAT IS KNOWN ALREADY: The first generation of donor insemination offspring of intended lesbian-parent families is now in their 30s. Coincident with this is an increased use of DNA testing and genetic ancestry websites, facilitating the discovery of donor siblings from a common sperm donor. Few studies of offspring and their DS include sexual minority parent (SMP) families, and only sparse data separately analyze the offspring of SMP families or extend the analyses to established adult offspring. STUDY DESIGN, SIZE, DURATION: This cohort study included 75 adult offspring, longitudinally followed since conception in lesbian-parent families. Quantitative analyses were performed from online surveys of the offspring in the seventh wave of the 36-year study, with a 90% family retention rate. The data were collected from March 2021 to November 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were 30- to 33-year-old donor insemination offspring whose lesbian parents enrolled in a US prospective longitudinal study when these offspring were conceived. Offspring who knew of a DS were asked about their numbers found, characteristics or motivations for meeting, DS terminology, relationship quality and maintenance, and impact of the DS contact on others. All offspring (with or without known DS) were asked about the importance of knowing if they have DS and their terminology, satisfaction with information about DS, and feelings about future contact. MAIN RESULTS AND THE ROLE OF CHANCE: Of offspring, 53% (n = 40) had found DS in modest numbers, via a DS or sperm bank registry in 45% of cases, and most of these offspring had made contact. The offspring had their meeting motivations fulfilled, viewed the DS as acquaintances more often than siblings or friends, and maintained good relationships via meetings, social media, and cell phone communication. They disclosed their DS meetings to most relatives with neutral impact. The offspring, whether with known or unknown DS, felt neutral about the importance of knowing if they had DS, were satisfied with what they knew (or did not know) of the DS, and were satisfied with their current level of DS contact. This study is the largest, longest-running longitudinal study of intended lesbian-parent families and their offspring, and due to its prospective nature, is not biased by over-sampling offspring who were already satisfied with their DS. LIMITATIONS, REASONS FOR CAUTION: The sample was from the USA, and mostly White, highly educated individuals, not representative of the diversity of donor insemination offspring of lesbian-parent families. WIDER IMPLICATIONS OF THE FINDINGS: While about half of the offspring found out about DS, the other half did not. Regardless of knowing of a DS, these adult offspring of lesbian parents were satisfied with their level of DS contact. Early disclosure and identity formation about being donor-conceived in a lesbian-parent family may distinguish these study participants from donor insemination offspring and adoptees in the general population, who may be more compelled to seek genetic relatives. The study participants who sought DS mostly found a modest number of them, in contrast to reports in studies that have found large numbers of DS. This may be because one-third of study offspring had donors known to the families since conception, who may have been less likely to participate in commercial sperm banking or internet donation sites, where quotas are difficult to enforce or nonexistent. The study results have implications for anyone considering gamete donation, gamete donors, donor-conceived offspring, and/or gamete banks, as well as the medical and public policy professionals who advise them. STUDY FUNDING/COMPETING INTEREST(S): No funding was provided for this project. The authors have no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Influence of family strength on life satisfaction of individuals who have a sibling with disability: Mediating effect of disability acceptance.

This descriptive correlational study was conducted to examine the mediating effect of disability acceptance on the relationship between family strength and life satisfaction in individuals who have a sibling with a disability. The responses of 144 non-disabled siblings of persons with a disability were analyzed using panel data from the Korea Institute for Persons with Disabilities, and a regression analysis was performed. Family strength and acceptance of disabilities significantly affected the life satisfaction of siblings without disability. Regarding the effect of family strength on life satisfaction, acceptance of a sibling's disability by siblings without disability had a significant mediating effect. Our results suggest that strategies to enhance the acceptance of disabilities and promote family strength are necessary to improve the life satisfaction of individuals without disability as well as their siblings with disabilities. Family-centered interventions are warranted to promote positive acceptance of disabilities.

Breastfeeding and the quality of the sibling relationship.

OBJECTIVE: To examine the association between the type of breastfeeding practiced and the quality of the sibling relationship. DESIGN: Cross-sectional study. METHOD: Participants were recruited between July and December 2019 through parenting associations and parenting support groups. They comprised a total of 149 mothers with two children between 2 and 7 years of age, who had practiced the same type of feeding with both children. Sibling relationship quality was assessed using the conflict/rivalry and warmth dimensions of the Parents' Expectations and Perceptions of Sibling Relationships with their Children (PEPC-SRQ) questionnaire. Analyses of covariance were used to identify any differences in these two dimensions of the PEPC-SRQ between the study groups (formula feeding, breastfeeding, non-prolonged breastfeeding, prolonged breastfeeding and tandem breastfeeding). RESULTS: No significant differences were observed between any of the groups regarding the conflict/rivalry dimension; in contrast, significant differences were found in the warmth dimension between the breastfeeding and formula feeding groups. CONCLUSIONS: Breastfeeding, regardless of its duration and simultaneity, was associated with higher scores in the dimension of warmth of the sibling relationship. IMPLICATIONS FOR PRACTICE: This information should be considered by healthcare professionals when providing advice on breastfeeding.

The impacts of typically developing siblings on the developmental outcomes of children with disability: A scoping review.

BACKGROUND: Siblings represent an important influence on children's development. It is possible that sibling influence on developmental outcomes differs in sibling pairs when one of the children has a disability. Previous research has tended to focus on outcomes for typically developing siblings when they have a brother/sister with a disability. AIMS: The purpose of this scoping review was to explore empirical studies reporting on the impact of siblings on the developmental outcomes of children with disability to better understand the areas that are influenced by siblings and the factors that contribute to this influence. METHOD: To identify relevant studies, the electronic databases of EBSCO, ERIC, Informit, Ovid, ProQuest and Scopus were searched. These searches were supplemented by direction from the authors on relevant literature and citation searches of papers identified for inclusion. Descriptive details were extracted, followed by details related to research design and findings of the studies. OUTCOMES AND RESULTS: Twenty-two papers were determined to meet inclusion criteria. Investigations of sibling influence have concentrated on children with ASD; other groups are not well represented. There is some evidence that having older siblings may be protective for children with ASD; however, this was not an invariable finding. There is too little consistency across studies to determine whether and how siblings influence development of children with disability. CONCLUSIONS AND IMPLICATIONS: Further work is required to understand the potentially crucial influence that siblings may have on developmental outcomes of children with disability.

Research Review: Siblings matter. A multi-level meta-analysis on the association between cannabis use among adolescent siblings.

BACKGROUND: Parents' and peers' cannabis use are well-documented predictors of youth cannabis use, however, relatively little is known about the influence of siblings' cannabis use. Hence, this meta-analysis investigated the association between sibling-youth cannabis use (disorder) and explored moderation by sibling type (monozygotic- vs. dizygotic- vs. non-twins), age, age spacing, birth order, gender, and gender constellations (same- vs. mix- gender pairs). When comparison data of parents' and peers' cannabis use (disorder) were also available in the included studies, separate meta-analyses on associations between parent-youth and peer-youth cannabis use (disorder) were additionally conducted. METHODS: Studies were selected if they included 11- to 24-year-old participants, and investigated associations between cannabis use (disorder) among those youth and their siblings. These studies were retrieved via a search in seven databases (e.g., PsychINFO). A multi-level meta-analysis using a random effects model was performed on the studies, and heterogeneity analyses and moderator analyses were also conducted. PRISMA guidelines were followed. RESULTS: We retrieved 20 studies (most of which originated from Western cultures) with 127 effect sizes for the main sibling-youth meta-analysis and found a large overall effect-size (r = .423), implying that youth had higher cannabis use rates when their sibling used cannabis, and this association was stronger for monozygotic twins and for same-gender sibling pairs. Finally, a medium effect size existed for the associations between parent-youth cannabis use (r = .300) and a large effect size for peer-youth cannabis use (r = .451). CONCLUSIONS: Youth are more likely to use cannabis when their siblings use cannabis. This sibling-youth cannabis use association existed for all sibling constellations, was larger than the association between parent-youth cannabis use, and was similar in magnitude compared to the association between peer-youth cannabis use-suggesting both genetic and environmental influences (e.g., social-learning) between siblings. Hence, it is important not to neglect sibling influences when treating youth cannabis use (disorder).

Chinese parents' marital and coparenting relationships, parental differential treatment of siblings, and adolescents' sibling relationships.

Parents' differential treatment of siblings has been understudied among sibling research in Chinese societies where the government ended its one-child policy. This study, using a three-wave longitudinal design, explored the associations among parents' marital and coparenting relationships, parental differential treatment of siblings, and adolescents' sibling relationships within a theoretical framework of a developmental cascade model of family influence. Adolescents (Mage = 12.88 years, SD = 0.76 at Time 1; 51.2% girls) and their mothers from 260 families in China participated in this research (first data collection in January 2018). Mothers completed questionnaires that assessed marital and coparenting relationship quality, and adolescents completed questionnaires that assessed their perceptions of parental differential treatment as well as sibling intimacy and conflict. The results, based on path analyses, revealed that marital satisfaction at Time 1 was positively associated with coparenting support at Time 2. Coparenting support at Time 2 was negatively associated with adolescents' perception of parental differential treatment at Time 3. Parental differential treatment at Time 3 was negatively associated with sibling intimacy at Time 3 but positively associated with sibling conflict at Time 3. These results are consistent with the developmental cascade hypothesis in that parent-parent subsystems influenced parental differential treatment of siblings as a parent-child subsystem, which in turn spilled over to create negative family processes that exacerbated adolescents' sibling subsystem quality. (PsycInfo Database Record (c) 2023 APA, all rights reserved).