**4. Discussion**

A total of 124 studies were systematically reviewed to identify relevant dimensions of family functioning associated with children's and adolescents' happiness. Four themes emerged from a review of these studies: (1) family dimensions and happiness; (2) global family functioning (i.e., family functioning and family relationships), environmental variables and happiness; (3) parental differences; (4) longitudinal studies.

Regarding the first theme, 91 studies examined the relationship between family dimensions (i.e., family cohesion and adaptability, family satisfaction and communication, and family conflict) and children's and adolescents' happiness. The results highlighted that family cohesion significantly predicted changes in happiness, life satisfaction, and positive affect over time [77,113,117,175]. In other words, increased family cohesion and adaptability were associated with higher levels of happiness in children and adolescents [20,110,122]. Thus, positive family dimensions may contribute directly to children's and adolescents' sense of happiness, contentment, and general life satisfaction [111,121].

Furthermore, in both boys and girls, positive communication with the mother and the father and high family satisfaction were directly associated with increased happiness [25,138,170,174]. The possibility to express oneself freely at home (i.e., to speak openly about any subject) was associated with greater life satisfaction for adolescents [114]. Adolescents who communicated effectively with their families probably felt that they could share their points of view and feelings openly and sincerely with their parents, and they may have interpreted this communication as a sign of parental support, trust, and closeness [30,140]. This may be especially true for girls, for whom the influence of family communication on happiness was slightly greater [27,171], possibly due to gender differences in cultural norms and socialization. Different parental socialization styles based on child gender [204] may also explain why communication tends to be more open between mothers and daughters and between fathers and sons [140].

On the other hand, communication problems and higher levels of family conflict were associated with lower happiness for children and adolescents [126,128,139]. When communication was open and trouble-free, children and adolescents were more likely to report satisfaction with their families, positive affect, and low levels of conflict, relative to children and adolescents who reported less communication with parents [30]. This finding suggests that family relationships which are perceived to be good may help children and adolescents develop feelings of freedom, love, and happiness [172], underlining that family dimensions play an essential role in influencing children's and adolescents' happiness [46].

As regards the second theme, 39 studies examined the association between global family functioning (i.e., family functioning and family relationships), family environment variables, and children's and adolescents' happiness. Specifically, a more positive perception of family functioning was related to better emotional well-being in children and adolescents [184,185,191,203]. Furthermore, regardless of the cultural background, children's family relationships influenced their levels of happiness [1,196] more significantly than any other variable. Bad parent–child relationships were usually accompanied by lower levels of family satisfaction and happiness [145]. Thus, feeling happy at home may contribute to both boys' and girls' happiness [174].

The reported studies provided support for the association between global family functioning and happiness during adolescence, even though adolescents consolidate new social relationships with friends and partners during this developmental period [36]. The family is the context in which the first emotional relationships develop, and where children learn to respect and establish positive relationships of love and respect for others [194]. Parents in a well-functioning family can provide emotional support to children, allowing them to express their emotions. A warm and open family communicates happiness to children [185], giving them a sense of security, emotional connection, and trust [178].

A subtheme of environmental factors associated with happiness concerned differences in sociodemographic variables. Some family factors predicted individual differences in happiness and life satisfaction during adolescence. In particular, more positive family environments were associated with greater happiness [191,197]. Furthermore, the findings supported both stability and change in perceived levels, and the relevance of certain life satisfaction domains, among children and adolescents. Young people who perceived a higher quality parent–child relationship had elevated and stable life satisfaction from middle adolescence (i.e., aged 14–16 years) to late adolescence (i.e., aged 17–18 years) [197].

Other studies found that young people's life satisfaction was negatively correlated with age in all global and life (i.e., family satisfaction) domains [48,146]. The decrease in happiness levels during this period suggests that pre-adolescence may be a stressful phase of development, during which cognitive, physical, and emotional changes strongly influence young people's overall sense of happiness [27]; family members may play an essential role in accompanying them through these changes. In particular, the decline in both family cohesion and happiness during early and middle adolescence (i.e., aged 12–16 years) may be explained by both the multiple challenges that adolescents face and the more significant conflict that they tend to experience with parents, which tend to result in less participation in family activities; this may reduce adolescents' perceived family cohesion and life satisfaction [117].

Regarding the third theme identified, 17 studies explored parental gender differences in the association between happiness and family functioning. The selected studies produced contradictory results: a single study reported that a positive mother–child relationship, but not a father–child relationship, was associated with greater happiness in children [43]. However, six studies found significant correlations with the father–child relationship and not the mother–child relationship [12,73,129,177,178,201]. These results sugges<sup>t</sup> that relationships with both mothers and fathers are relevant to children's and adolescents' happiness.

However, the reviewed studies found that the father–child relationship was more closely related to indicators of happiness in adolescents than the mother–child relationship [12,73,129]. Indeed, the father–child relationship, father–child cohesion, and father– child conflict predicted children's life satisfaction, while no equivalent associations were

found for the mother [129,177,178]. These results sugges<sup>t</sup> that the effect of father–child proximity on children's and adolescents' development is not related to mother–child proximity [178].

However, these studies, which sugges<sup>t</sup> that fathers have the most significant impact on children's and adolescents' well-being, contradict the literature showing that mothers tend to be more significant in determining child developmental outcomes. While fathers tend to spend less time with children relative to mothers [205], they may be more committed and dedicated to children when they do spend time together, focusing on the specific situation at hand. Children may perceive their father's behavior as an essential aspect of their relationship that increases their happiness over the long term [73]. Future studies should investigate the differences between mothers and fathers and the different perspectives between parents and children, to better understand these aspects.

Finally, the last theme that emerged (13 studies) highlighted the importance of evaluating the relation between happiness and family functioning over time, from a predictive perspective. Several studies showed that, regardless of the informant (i.e., father, mother, or child) and the sequence of data collection (i.e., simultaneously vs. longitudinally), children's happiness was correlated with family functioning [89,181]. The results of both the simultaneous and longitudinal studies consistently showed that the cognitive component of happiness (i.e., life satisfaction) was significantly associated with family functioning and family relationships [22,43,199]. In addition, the longitudinal studies suggested that the relation between perceived family functioning and adolescents' happiness may be bidirectional [24]; therefore, it is not possible to confirm a univocal causal link between these factors.

Regarding subdimensions of family functioning, studies found that family cohesion [110,175], family communication [176], and parent–adolescent conflict [89,129] significantly predicted changes in adolescent happiness over time: more significant parent– adolescent conflict at Time 1 tended to be associated with a decline in adolescent life satisfaction at Time 2 [89], and greater family cohesion and open communication with parents tended to be associated with increased life satisfaction over time [117,176]. Also, concerning family conflict, the data showed that the relation between parent–adolescent conflict and adolescent emotional well-being could be bidirectional [89]. Future studies should further investigate the causal links between individual and family variables.

In conclusion, the findings of this study sugges<sup>t</sup> that family dimensions may influence the affective and cognitive components of children's and adolescents' happiness [30,46,77,110–112,124,125,135]. In particular, the reviewed findings demonstrate the significance of family bonds and support for adolescents, indicating that, when family members provide help, affection, and understanding, children and adolescents experience multiple benefits that undoubtedly affect their development of positive psychological experiences [145,200].

#### *Limitations and Strengths of the Studies, and Future Research Directions*

Despite increasing research interest in the relation between happiness and family functioning (as evidenced by the growing number of publications in recent years), the investigated studies suffered from some methodological limitations. First, the use of selfreport measures may have exposed the research to social desirability bias. Future studies should employ a multi-informant and multi-method methodology combining qualitative measures (i.e., structured or semi-structured interviews and observational measures) or multi-informant questionnaires (i.e., parent and teacher reports) with self-reports. Second, the use of cross-sectional designs did not enable causal links to be drawn between variables. Thus, future studies should implement longitudinal procedures to better understand the factors that contribute to the happiness of children and adolescents. Furthermore, the heterogeneity of the samples (with respect to, e.g., geographical scope, size, and age range) limit the generalizability of the results.

The lack of a coherent theoretical model to define the construct of happiness represents a significant gap in the literature. This may explain the variety in both measurement tools and operationalizations of the construct in the investigated studies. Compounding this, some of the investigated studies did not clearly define happiness, positive affect, or life satisfaction. Therefore, future research should explicitly make the psychological construct operational. Additionally, future research should explore the association between attachment styles and children's and adolescents' happiness during development.

A further limitation of the present research is the possibility that methodological biases may have affected the study selection, due to the arbitrariness of the constructs and the interpretation of the reviewers. However, two independent evaluators excluded all articles that deviated from a precise definition of happiness or that analyzed family factors other than family functioning. Thus, attempts were made to target the constructs of interest.

A future research direction might be to examine overall effect sizes, which were not addressed in the present study. Moreover, as the present work focused on the relation between happiness and family functioning in non-clinical samples, an equivalent analysis in clinical samples may provide important new insights. Finally, the present review suggests the relevance of the father–child relationship, father–child cohesion, and father–child conflict in predicting children's and adolescents' happiness. Future research should further investigate the differences between fathers and mothers, using multi-informant and mixedmethods procedures and a longitudinal approach.

However, the present work also has significant strengths, including compliance with a rigorous systematic review protocol with clearly-defined inclusion and exclusion criteria. Indeed, a careful research strategy carried out by two independent evaluators was employed to acquire all relevant articles. Another strength is the high reviewer reliability during the screening process, reflecting a transparent selection methodology. Uniquely, the review represents the first study to synthesize the literature on happiness in the family context during development, filling a significant gap in the literature pertaining to the possible impact of family functioning on children's and adolescents' happiness. Finally, the review identified heterogeneous measurements of happiness and family functioning during development, suggesting that future studies should develop a more standardized approach to obtain more consistent results.
