Table 2. Information about programme theories and findings for included studies concerned with children (3 to 9 years).

Study ID	Intervention components	Context	Mechanisms for improved child mental health	Social support outcomes	Child outcomes
Ayton and Joss (2016) [32]	Teaching parents social and parenting skills to develop relationships with others and establishing community connections and social networks Addressing social determinants of health and remove barriers Offering practical and emotional support	Vulnerable and isolated parents affected by intergenerational poverty (excluding those with unmanaged violence, debt, etc.)	Improved parenting skills leading to child health and wellbeing	Parents experienced improvements in social support provided by the mentor (in addition to other improvements in employment, housing, mental health, drug and alcohol use)	Improved parent-child relationships (because of increase in parental emotions and skills) Improvements in social determinants of child (mental) health (but no evidence on child mental health presented)
Branch et al (2013) [38]	Broadening understanding by professionals of interconnectedness and interdependencies of child’s life Improving strength of relations between different levels of organisations (mainly schools) involved in child’s life	Most families alienated from school; language barriers, cultural factors; historically disastrous experiences with government for indigenous people Children with medium to high needs; withdrawn or aggressive behaviour; health problems; isolation related to language	Mutual responsibility among professionals to improve child wellbeing leads to innovative solutions that are expected to improve child wellbeing	New relationships especially between schools and families as parents lost fear of institutions and started to build trust (collected via prompts about connections in qualitative interviews)	Evidence of adjustments made by school, parents and programme staff with benefit for child’s behaviour and school attendance (but no evidence on child outcomes presented)
Byrne et al (2012) [37]	Reinforcing parents’ perception of social support and increasing their satisfaction with social support networks Teaching parenting skills	At risk families often without mutual supportive relationships including with partner Parents have negative perception and distrust towards services and are less likely to accept formal support	Improved parenting skills assumed to improve child development and wellbeing Parent satisfaction with formal and informal support hypothesised to increase help seeking behaviour including help for child development support	Parents’ increased satisfaction with and use of informal and—to a lesser extent—formal support (e.g. neighbourhood associations, child welfare support)	Improved parental outcomes (e.g. agency) linked to increase in perceived social support (but no evidence on child mental health presented) Some evidence that stronger positive effects of informal support and of negative effects of ‘too much’ formal support on parental agency
Doty et al (2017) [39]	Teaching parenting skills Building positive emotions Increasing confidence of parents to mobilise needed support for child and build social capital for benefit of child health and academic achievements	Economic disadvantaged families with certain level of extant social capital	Children’s develop early socioemotional skills due to increased social capital of parents, which help them to build or have access to supportive social networks, which in turn is associated with psychological and social adjustment in later adulthood	Improved relationships among family members and between family members and social networks	Improved school attendance and grade promotion; fewer risk behaviours
Drummond et al (2014) [40]	Service integration to increase access to formal support for families Parental involvement with childcare and schools hypothesised to lead to richer social support networks	Low income families, including aboriginal and other minorities populations; families on government assistance programme	Family functioning hypothesised to influence family linkage to services and health outcomes Better school achievements for children when parents more involved with schools Child engagement in recreation activities hypothesised to lead to improved child wellbeing	N/A (protocol)	N/A (protocol)
Eddy et al (2017) [41]	Provide opportunities for child to participate in enriching experiences that enhance ability to envision a positive future Providing social support opportunities for children—like access to academic assistance and health care	Children at risk; living in disadvantaged areas	Children build and engage in social relationships with others including peers, teachers, parents; this is expected to improve child social-emotional, cognitive and identity development	Increased received social support from mentors (in form of long-term relationships)	Significant effects in terms positive child behaviour and less trouble in school; and trend for higher child behavioural and emotional strengths
Ingram et al (2015) [42]	Teaching parents skills how to asks for and utilise social support (e.g. active listening, modelling, guided practice)	Socially isolated families, many have child protection record (children still living with parent); exposed to multiple stressors	Increased parental capacity and improved family interactions expected to reduce child behaviour problems and improve school attendance and achievements	Increased social support available to parents and improved family relationships	Improved child well-being (moderate effects), in addition to improved school attendance and reduced youth crime
Lachman et al (2017) [43]	Teaching parenting skills and non-violent behaviour towards children	Low and middle income country context with high rates of HIV, drug and alcohol addictions and violence Intervention provided by low skilled staff	Increased parent’s social support and self-efficacy expected to reduce risk of child maltreatment and to lead to improved child behaviour and socio-emotional regulation skills (role of social support not well described)	No significant differences in parent’s perceived social support	Negative effect on child behaviour
Marcynyszyn et al (2011) [44]	Teaching parenting skills (in particular managing child behaviour)	Parents involved in child welfare system	Satisfaction with support provided is assumed to influence child outcomes through retention in programme (role of social support not well described)	Parents reported higher levels of family support, and (to a lesser extent) friend support Perceived helpfulness of resources largely unchanged other than for parenting group itself	Improved child behaviour; reduced child difficulties (small effects)
Nabuco et al. (2014) [45]	Teaching parenting skills to seek for support for child Providing opportunities for parents in the same community to discuss information and ideas, share experiences, offer support	Families in poverty and lack of social networks and support; children lack bonding with parents; low self-esteem; poor literacy/numeracy skills; majority of children did not attend any preschool programme	Increased parenting knowledge, empowerment and resources for educating children leads to better cognitive and social development	Higher social support perceived by parents in the intervention group	Improvements in child cognitive and social development
Pancer et al. (2013) [46]	Providing information about community services and resources Changing the environment	Areas with substantial neighbourhood disadvantage and significant risks for child development	Skills to access community resources Parents feeling sense of connection with others in their community Child benefits from increased access to support	No significant changes in: parent-reported social support; parent involvement in social activities; youth community involvement	Not differences in child behaviour problems or social skills
Parcel and Pennell (2012) [47]	Joint planning to support children in school Participatory decision making and trust building processes with parents Strengthening linkages within the family and linkages to school and community organisations	Low-income families and neighbourhoods, black and ethnic minorities, children at risk of academic failure	Increase in family and school social support hypothesised to predict academic achievement and social adjustment and behaviour outcomes for children	Improved relationships within families	Improved mental health, academic achievements, reduction in youth crimes; improved family functioning
Vazquez et al. (2017) [48]	Teaching parents about child development	High proportion of immigrants, mainly from Latin America; described as having complex lives; parents report feeling isolated	No hypotheses stated	Increased social support as perceived by parents; parents no longer feeling isolated in their parenting role Parents viewed the program as source of social support because of program contents, facilitator strategies, support from parents, and by institutions and community	Reduced negative child behaviour and increased school performance