Multifinality, equifinality, and the elusive complexity of developmental trajectories revisited

Research over the past decades has clearly demonstrated the intricate interplay of psychological, biological, and sociocultural factors in psychological developmental processes in both typical and atypical development (Handley et al., Reference Handley, Russotti, Rogosch and Cicchetti2019; Jolicoeur-Martineau et al., Reference Jolicoeur-Martineau, Belsky, Szekely, Widaman, Pluess, Greenwood and Wazana2020; Kochanska & An, Reference Kochanska and Anin press; Masten et al., Reference Masten, Lucke, Nelson and Stallworthy2021; McCrory et al., Reference McCrory, Foulkes and Viding2022; Pollak, Reference Pollak2015; Russotti et al., Reference Russotti, Warmingham, Duprey, Handley, Manly, Rogosch and Cicchetti2021; Verhage et al., Reference Verhage, Fearon, Schuengel, van IJzendoorn, Bakermans‐Kranenburg, Madigan, Roisman, Oosterman, Behrens, Wong, Mangelsdorf, Priddis and Brisch2018; Zeegers et al., Reference Zeegers, Colonnesi, Stams and Meins2017). In our opinion, two major sets of findings have emerged in this context, which have considerably changed our understanding of the nature of psychological development. The first set of findings concerns the major role of early adversity in determining both physical and mental health (Reference Smith and Pollak2021b; Hogg et al., Reference Hogg, Gardoki-Souto, Valiente-Gómez, Rosa, Fortea, Radua, Amann and Moreno-Alcázar2023; Madigan et al., Reference Madigan, Deneault, Racine, Park, Thiemann, Zhu, Dimitropoulos, Williamson, Fearon, Cénat, McDonald, Devereux and Neville2023; McCrory et al., Reference McCrory, De Brito and Viding2012, Reference McCrory, Foulkes and Viding2022; Pollak, Reference Pollak2015, Smith & Pollak, Reference Smith and Pollak2021a). The second relates to findings concerning the ubiquitous nature of resilience, and thus plasticity and change, particularly in critical periods in psychological development (Bonanno & Diminich, Reference Bonanno and Diminich2013; Denckla et al., Reference Denckla, Cicchetti, Kubzansky, Seedat, Teicher, Williams and Koenen2020; Masten et al., Reference Masten, Lucke, Nelson and Stallworthy2021). In both of these areas, Cicchetti and his colleagues have made key contributions (Cicchetti & Toth, Reference Cicchetti and Toth2005; Denckla et al., Reference Denckla, Cicchetti, Kubzansky, Seedat, Teicher, Williams and Koenen2020; Russotti et al., Reference Russotti, Warmingham, Duprey, Handley, Manly, Rogosch and Cicchetti2021).

Early developmental theorists cautioned against overly narrow and simplistic explanations of psychological development. For instance, Anna Freud (Reference Freud1981) emphasized the importance of simultaneously considering different developmental lines and their intricate interactions; Erik Erikson (Reference Erikson1959) highlighted the interaction among psychological and cultural factors in his epigenetic theory of human development across the lifespan; and Bronfenbrennerʼs (Bronfenbrenner, 1977; Bronfenbrenner & Morris, Reference Bronfenbrenner, Morris, Damon and Lerner2007) bio-ecological approach focused on complex interactions among psychosocial and biological factors in psychological development. Consistent with the views of these pioneers, it has become increasingly clear that predicting developmental outcomes is difficult (Smith & Pollak, Reference Smith and Pollak2021a) not least because of the role of chance events and stochastic processes in explaining psychological development (Fraley & Roberts, Reference Fraley and Roberts2005). This confronts us with a problem that was described more than a century ago by Sigmund Freud when he discussed the issue of predicting later development from childhood to later adulthood:

Freud’s views foreshowed Dante Cicchetti and Fred Rogosch’s (Reference Cicchetti and Rogosch1996) notions of equifinality and multifinality which revolutionized our thinking concerning psychological development. Equifinality captures how a single developmental outcome may be influenced by multiple risk or protective factors, while multifinality implies that one particular risk or protective factor may result in multiple outcomes. Although both notions have been massively helpful in developmental psychopathology, and have greatly fostered a move toward more transdiagnostic and transtheoretical approaches in developmental psychopathology and beyond (discussed in more detail below), we are now – perhaps more than ever – confronted with the elusive problem of prediction in developmental psychopathology. This is the case particularly because, with some exceptions, most associations between developmental factors and later outcomes are typically at best small to modest (Fearon et al., Reference Fearon, Bakermans-Kranenburg, van Ijzendoorn, Lapsley and Roisman2010; Groh et al., Reference Groh, Roisman, van Ijzendoorn, Bakermans-Kranenburg and Fearon2012; Luyten et al., Reference Luyten, Campbell and Fonagy2021; Zeegers et al., Reference Zeegers, Colonnesi, Stams and Meins2017). This issue poses challenges not just in research but also in the realms of prevention and intervention. For example, it is crucial to discern between the typical developmental upheaval characteristic of adolescence and the signs of emerging personality disorder (Fonagy, Speranza, et al., Reference Fonagy, Speranza, Luyten, Kaess, Hessels and Bohus2015; Hutsebaut et al., Reference Hutsebaut, Debbané and Sharp2020). Similarly, there is a question about whether we should persist in focusing on a limited set of presumed specific vulnerability factors in psychosocial interventions designed for particular psychological disorders. This approach may be less effective if these specific factors account for only a small portion of the variance in developmental outcomes, especially considering the substantial evidence for the role of broader transdiagnostic factors involved in equifinality and multifinality (Leichsenring et al., Reference Leichsenring, Steinert, Rabung and Ioannidis2022; Norton & Paulus, Reference Norton and Paulus2016; Weisz et al., Reference Weisz, Kuppens, Ng, Vaughn-Coaxum, Ugueto, Eckshtain and Corteselli2019).

How we can we improve our ability to predict developmental outcomes in the future and use this knowledge to improve our intervention strategies? One potential avenue seems to be provided by recently emerging hierarchical models of psychopathology and personality development. Research on a general psychopathology factor and a bifactor model of psychopathology is likely to be greatly helpful in elucidating both equifinality and multifinality in developmental outcomes in the future. The bifactor model basically argues that a single general psychopathology factor or “p” factor, akin to a general (“g”) factor in research on intelligence, explains the covariance between higher-order factors of psychopathology such as internalizing, externalizing, and thought disorder features and specific symptom domains (Caspi et al., Reference Caspi, Houts, Belsky, Goldman-Mellor, Harrington, Israel, Meier, Ramrakha, Shalev, Poulton and Moffitt2014; Caspi & Moffitt, Reference Caspi and Moffitt2018; Choate et al., Reference Choate, Bornovalova, Hipwell, Chung and Stepp2023; Lahey et al., Reference Lahey, Moore, Kaczkurkin and Zald2021; Smith et al., Reference Smith, Atkinson, Davis, Riley and Oltmanns2020). The p factor is thus assumed to represent a general predisposition to mental disorder; it follows from this that the p factor should correlate with known risk factors for psychopathology. Consistent with these assumptions, higher p factor scores are associated with known vulnerability factors for psychopathology, including early adversity, markers of socioeconomic disadvantage, and disruptions in brain function and brain structure (Caspi & Moffitt, Reference Caspi and Moffitt2018; Patalay et al., Reference Patalay, Fonagy, Deighton, Belsky, Vostanis and Wolpert2015). Moreover, the p factor overlaps with genomic and neural “p factors”, that is, genetic factors and impairments in neural functioning that are implicated in a wide variety of psychological disorders and problems (Sprooten et al., Reference Sprooten, Franke and Greven2022). Crucially, research findings suggest that the p factor explains more of the variance in developmental outcomes than specific vulnerability factors do (Caspi & Moffitt, Reference Caspi and Moffitt2018; Patalay et al., Reference Patalay, Fonagy, Deighton, Belsky, Vostanis and Wolpert2015), and there is emerging research that a general psychopathology factor also predicts treatment response in psychosocial interventions over and above lower-bandwidth factors (Constantinou et al., Reference Constantinou, Goodyer, Eisler, Butler, Kraam, Scott, Pilling, Simes, Ellison, Allison and Fonagy2019; Fiorini et al., Reference Fiorini, Saunders, Fonagy and Midgley2022). Furthermore, the p factor is also likely to be involved in active person–environment transactions, in that individuals with high p factor levels may unconsciously create, in part, their own stressful environment (Smith et al., Reference Smith, Atkinson, Davis, Riley and Oltmanns2020).

The relevance of a bifactor model of psychopathology for developmental psychopathology is further increased if we consider the p factor as indicative of problems with the capacity for social learning and epistemic trust in particular (Fonagy et al., Reference Fonagy, Campbell, Constantinou, Higgitt, Allison and Luyten2022; Luyten et al., Reference Luyten, Campbell and Fonagy2021). Epistemic trust refers to an evolutionarily prewired capacity to identify knowledge that is conveyed by others as significant, personally relevant, and generalizable to other contexts. It is thought to facilitate resilience through a health-generating (salutogenic) process facilitated by social learning.

Evolutionary research suggests that the development of epistemic trust is a species-specific ability that allows the kinds of sophisticated and complex forms of communication and collaboration that are typical of humans (Tomasello, Reference Tomasello2010), particularly in combination with another species-specific ability, namely, the capacity to mentalize. From a developmental perspective, the combination of the emerging capacity for mentalizing and epistemic trust seems to open in children what we have termed an “epistemic superhighway” allowing the developing child to take in social information conveyed by informants who are considered by the child to be trustworthy.

The development of both mentalizing and epistemic trust is complex, in that epistemic vigilance is the default mode of functioning in children as, from age 3 onward, they begin to develop the capacity for selective trust in knowledge conveyed by others (Coan & Sbarra, Reference Coan and Sbarra2015; Fonagy & Luyten, Reference Fonagy and Luyten2018; Fonagy et al., Reference Fonagy, Luyten, Allison and Campbell2017; Gergely, Reference Gergely, Metcalfe and Terrace2013; Konner, Reference Konner2010; Sperber et al., Reference Sperber, Clement, Heintz, Mascaro, Mercier, Origgi and Wilson2010; Tomasello, Reference Tomasello2010). The early caregiving environment and, later on, the sociocultural environment more generally, appears to play a crucial role in overcoming epistemic vigilance in children and in allowing them to develop an adaptive epistemic stance toward cultural knowledge (Allen, Reference Allen2021; Fonagy et al., Reference Fonagy, Luyten, Allison and Campbell2017). In this regard, it is as yet not clear what impact the current epistemic crisis, in which children and young people in particular are being subjected to a torrent of socio-digital information whose trustworthiness is often unclear, will have on children’s and young people’s psychological development.

Again, hierarchical models of psychopathology and personality (Bleidorn et al., Reference Bleidorn, Hopwood, Back, Denissen, Hennecke, Jokela, Kandler, Lucas, Luhmann, Orth, Roberts, Wagner, Wrzus and Zimmermann2020; Hopwood et al., Reference Hopwood, Wright and Bleidorn2022; Widiger et al., Reference Widiger, Sellbom, Chmielewski, Clark, DeYoung, Kotov, Krueger, Lynam, Miller, Mullins-Sweatt, Samuel, South, Tackett, Thomas, Watson and Wright2018) provide a potentially productive approach in this context, as they specify both general personality-related factors (such as a general p factor) and more specific personality features that might be involved in person–environment correlations and interactions, leading to more fine-grained predictions about developmental outcomes. For instance, employing Waddington’s (Reference Waddington1957) metaphor of an epigenetic landscape, the personality or temperamental dimensions identified in multivariate studies could steer children in certain directions within the epigenetic landscape, affecting their capacity for epistemic trust (Luyten & Fonagy, Reference Luyten and Fonagy2022). Specific genetic predispositions, as manifested in low levels of temperamental factors such as effortful control and executive functioning, might negatively influence the development of epistemic trust. High levels of neuroticism, a temperamental factor that also has a high genetic component, might impact the development of secure attachment relationships in infants and thus their ability to trust others as sources of social information and thus hinder salutogenic processes. Similarly, the presence or absence of responsive caregivers or mentors, influenced by active relationship-recruiting capacities and/or chance, could alter individuals’ epistemic stance – and thus their capacity for social learning – over time. Broader aspects of the sociocultural climate in which children are raised, like the presence or absence of social capital (i.e., shared values or resources that allow individuals to work together in a group) within a given (sub)cultural context, may partly shape a developing child’s perception of others (Smith & Pollak, Reference Smith and Pollak2021b; Xu et al., Reference Xu, Harms, Green, Wilson and Pollak2023) and, ultimately, their capacity for epistemic trust. These perspectives align with contemporary views of personality and personality pathology, suggesting that personality fundamentally serves as a subjective intrapsychic system for fulfilling adult life tasks, highlighting the role of individuals as agentic actors in interpreting and managing the self. From this perspective, specific personality traits may influence the expression and manifestations of personality and personality pathology (Sharp & Wall, Reference Sharp and Wall2021).

Artificial Intelligence (AI) is extremely likely to facilitate research in this area. For example, epistemic trust, epistemic mistrust, and epistemic credulity (Campbell et al., Reference Campbell, Tanzer, Saunders, Booker, Allison, Li, O’Dowda, Luyten and Fonagy2021) could be viewed as variables within a Bayesian framework, with the p factor reflecting a general impairment in the capacity to revise hypotheses (i.e., beliefs about the world, and especially about others) in the light of current experience, resulting in an apparent rigidity manifested as impairments in the ability for (social) learning. Hence, internal working models of the self and others, as traditionally conceived within many developmental psychopathology approaches, may contain not only an expectancy parameter but also an expected outcome and learning parameter from this perspective. More specific personality traits, such as neuroticism, openness to experience, and agreeableness, could enhance or inhibit the updating of social information, much like certain caregiving practices or broader sociocultural environments might. With the growing accessibility and capabilities of AI and computational psychiatry methods more broadly, the future is likely to witness increasingly sophisticated modeling of developmental trajectories along these suggested lines.

Incorporating communities and culture in developmental psychopathology approaches

Developmental psychopathology approaches have become increasingly more contextual in the past few decades. This has also come with an increasing realization that, historically, most research in psychology has been based on individuals in “WEIRD” (Western, Educated, Industrialized, Rich, and Democratic) countries, who constitute only slightly more than 10% of the global population (Henrich, Reference Henrich2020). Likewise, less than 10% of studies investigating gene–environment interactions are based on non-Western samples (Leighton et al., Reference Leighton, Botto, Silva, Jimenez and Luyten2017). Cicchetti has in this context consistently emphasized the importance of the broader social environment in child development (Beeghly & Cicchetti, Reference Beeghly and Cicchetti1994; Cicchetti & Toth, Reference Cicchetti and Toth2005).

Our own perspectives on normal and disrupted development have similarly evolved over the past decade. Initially, we placed significant emphasis on the role of dyadic attachment processes and the development of mentalizing abilities within close attachment relationships as key factors in explaining developmental paths. However, our focus has since expanded to a broader, evolutionarily-informed, social-communicative approach. This more comprehensive perspective includes the influence of family, peers, and sociocultural factors at large in the development of a psychological self (Fonagy et al., Reference Fonagy, Campbell, Constantinou, Higgitt, Allison and Luyten2022; Luyten et al., Reference Luyten, Campbell, Allison and Fonagy2020).

Two strands of research have contributed to this shift in our thinking. First, based on evolutionary-based research, in particular the work of Tomasello and colleagues (O’Madagain & Tomasello, Reference O’Madagain and Tomasello2019; Tomasello, Reference Tomasello2020a, Reference Tomasello2020b), we have increasingly come to realize that the role of impairments in the capacity for mentalizing far exceeds the importance we ascribed to them in understanding psychopathology. There is increasing evidence that mentalizing is a central human capacity, rooted in joint attention and shared intentionality, that plays a pivotal role in both normal and disrupted psychological development, in that it enables the complex forms of communication and collaboration, and thus (social) learning, that are typical of humans. Second, the work of Gergely and Csibra on their theory of natural pedagogy (Csibra & Gergely, Reference Csibra and Gergely2009; Gergely, Reference Gergely, Metcalfe and Terrace2013), Konner’s views of childhood as reflecting a process of enculturation made possible by the evolution of a cultural acquisition device (Konner, Reference Konner2010), Tomasello’s cultural intelligence hypothesis (Tomasello, Reference Tomasello2010), social baseline theory (Coan & Sbarra, Reference Coan and Sbarra2015), and Sperber and colleagues’ groundbreaking work on epistemic vigilance in humans (Sperber et al., Reference Sperber, Clement, Heintz, Mascaro, Mercier, Origgi and Wilson2010) drew our attention to the potential role of epistemic trust in explaining the fast transmission of social information that is typical of most human learning processes. We now assume that epistemic trust is likely to play a key role in resilience through a salutogenic process that involves deriving benefit from relevant information accessible through the social environment (Campbell et al., Reference Campbell, Tanzer, Saunders, Booker, Allison, Li, O’Dowda, Luyten and Fonagy2021; Fonagy et al., Reference Fonagy, Campbell, Constantinou, Higgitt, Allison and Luyten2022).

This led to a substantial shift in our understanding of the nature of several key developmental processes. Research on attachment and personality provides a good illustration of this change in our views (Luyten et al., Reference Luyten, Campbell and Fonagy2021). Although we still believe that research findings are consistent with the assumption that a secure attachment context fosters a broad array of psychological processes, ranging from cognitive development to the acquirement of socioemotional skills and capacities, we have also come to realize that the importance of (early) attachment relationships for children partly lies in learning to recognize who is trustworthy, authoritative, and knowledgeable (Corriveau et al., Reference Corriveau, Harris, Meins, Fernyhough, Arnott, Elliott, Liddle, Hearn, Vittorini and de Rosnay2009; Fonagy et al., Reference Fonagy, Campbell, Constantinou, Higgitt, Allison and Luyten2022). Furthermore, we now consider secure attachment an important, but not the only – and in some cultural contexts not even necessary – context for social communication to promote the most effective way to function in a given sociocultural environment. Broader social contextual factors (e.g., peers, neighborhood climate, the social capital in a given cultural environment, and, last but not least in the digital era, social media) are likely to influence the development of attachment and epistemic trust over time. From this perspective, we no longer consider attachment or personality styles as something that reside within the individual, but as something that defines the relationship an individual has with others and their social contexts more generally. Put otherwise, attachment and personality styles are seen as communicative strategies underpinning social learning to ensure adaptation to ever-changing social situations, however “maladaptive” or “rigid” this adaptation strategy may seem. Yet, the rigidity or maladaptiveness we now posit is in the eye of the beholder. For instance, the often pervasive mistrust that is typical of individuals with high levels of dismissive and disorganized attachment (Campbell et al., Reference Campbell, Tanzer, Saunders, Booker, Allison, Li, O’Dowda, Luyten and Fonagy2021) should be considered a reasonable and understandable attempt to adapt to the unavailability and/or untrustworthiness of others, often as part of a “risky environment” (Cicchetti & Toth, Reference Cicchetti and Toth2005). This view opens up interesting perspectives for intervention, as the “rigidity” or “hard-to-reach” nature of the individual is not situated primarily in the individual but in the relationship between the individual and their context, and thus may be apparent only as long as the mechanisms responsible for the obstruction to epistemic trust are in place.

Further, as noted, dyadic attachment processes and emotional sensitivity are unlikely to be the exclusive route for generating epistemic trust and salutogenesis. For instance, alloparenting, which involves caregiving by multiple caregivers without specific division of tasks based on location or time, is widely prevalent in numerous non-Western countries (Dagan & Sagi-Schwartz, Reference Dagan and Sagi-Schwartz2021; Hawks & Meehan, Reference Hawks, Meehan, Keller and Otto2014; Hrdy, Reference Hrdy2016). This practice may even be an adaptation to challenging environments, reflecting a response to adversity (Martin et al., Reference Martin, Ringen, Duda and Jaeggi2020). Caregiver–child interactions involving play and conversation tend to be less frequent in many non-Western cultures, and often do not conform to the “interactional script” commonly observed in Western countries. Viewing the child as a “social apprentice,” it is crucial for the child to experience moments of recognition and a sense of joint intentionality that provide clear guidance on how to behave within their community. A focus on attachment, emotions, and psychological states typifies a Western “script” in this context, but there are numerous other possible scripts (Mesman et al., Reference Norton and Paulus2016, Reference Mesman, Minter, Angnged, Cisse, Salali and Migliano2018). The significant benefit of a secure attachment relationship, when viewed in the context of groups rather than individuals, is that it facilitates the child’s orientation toward cultural learning opportunities from their environment (Fonagy et al., Reference Fonagy, Campbell, Constantinou, Higgitt, Allison and Luyten2022).

Finally, there may be important cultural differences in terms of which patterns of behavior are considered to reflect normal personality variations and at various levels of the p factor. For example, there are important cultural differences in attitudes toward more introvert, schizoid personality features, which seem to be valued more in many non-Western countries than in many Western cultures. At higher levels of p factor, psychotic thoughts and beliefs may be considered to be less pathological in some cultures than in others (Paniagua, Reference Paniagua, Cuéllar and Paniagua2000).

The interplay of genes and environment

Developmental psychopathology research has greatly expanded our knowledge of key neurobiological systems, such as those involved in stress, reward, and social cognition, and their role in psychological development. Similarly, the insights from both behavioral and molecular genetic studies have significantly altered our understanding of the role of genetic factors in developmental processes. This is particularly true since the advent of research on gene–environment correlations, interactions, and epigenetics. In this field, Cicchetti and colleagues have contributed several seminal studies (Handley et al., Reference Handley, Russotti, Ross, Toth and Cicchetti2023; Raby et al., Reference Raby, Cicchetti, Carlson, Cutuli, Englund and Egeland2012).

However, a persistent issue has been the difficulty in replicating findings, especially in the realms of gene–environment correlations, interactions, and epigenetics (Bleys et al., Reference Bleys, Luyten, Soenens and Claes2018; Golds et al., Reference Golds, MacBeth and de Kruiff2020; Leighton et al., Reference Leighton, Botto, Silva, Jimenez and Luyten2017; Martins et al., Reference Martins, Yusupov, Binder, Brückl and Czamara2022; Picardi et al., Reference Picardi, Giuliani and Gigantesco2020; Smeeth et al., Reference Smeeth, Beck, Karam and Pluess2021). This challenge may be partly due to the identification of a general genetic factor involved in many developmental outcomes throughout the lifespan, leading to a lack of specificity in genetic factors in psychological development. This raises complex questions about equifinality and multifinality. Moreover, although the heritability of many developmental constructs appears substantial, in the domain of gene–environment interaction, epigenetics, and genome-wide association studies, typically only small effect sizes have been observed. Most studies have also relied on post-hoc analyses of existing data sets. Consequently, there is a pressing need for preregistered, large-scale, prospective studies using more diverse samples. Much current research may rely on what could eventually be considered “shallow” phenotyping, based on a limited set of developmental factors and a variable-centered approach. Therefore, “deep phenotyping” or “deep ecophenotyping,” which adopts a person-centered perspective and develops phenotypes or ecophenotypes based on individual characteristics across various domains (e.g., family, friendship and romantic relationships, academic achievement, community engagement), may be a more effective approach in developmental genetics. Furthermore, advancements in AI and experimental psychopathology are increasingly enabling the development of more sophisticated typologies of individuals, which could have significant implications for psychosocial interventions (Schiele et al., Reference Schiele, Gottschalk and Domschke2020).

Mentalizing, mind-mindedness, and mental-state language

Thirty years ago, Beeghly and Cicchetti (Reference Beeghly and Cicchetti1994) demonstrated that toddlers who experienced maltreatment and had insecure attachment exhibited the most compromised internal-state lexicon compared to other children. Cicchetti and colleagues have always maintained that psychological development follows a series of qualitative reorganizations within and between biological and psychological systems, involving differentiation and subsequent hierarchical integration of psychological capacities (Cicchetti & Toth, Reference Cicchetti and Toth2005; Doyle & Cicchetti, Reference Doyle and Cicchetti2017). A child’s own ability for mentalizing and epistemic trust, combined with access to a mentalizing environment, is likely to encourage this reorganization. In a similar vein, Cicchetti, alongside various colleagues, developed and validated a narrative coding system to evaluate the effective resolution of trauma. In longitudinal studies, these researchers discovered that resolving maternal trauma had a protective-enhancing impact on maternal sensitivity (Swerbenski et al., Reference Swerbenski, Sturge-Apple, Messina, Toth, Rogosch and Cicchetti2023).

These findings align with a growing body of research indicating that parental reflective functioning, and specifically caregivers’ ability to reflect on their own traumatic experiences, plays a protective role in the dynamics between parental trauma and child outcomes (Berthelot et al., Reference Berthelot, Savard, Lemieux, Garon-Bissonnette, Ensink and Godbout2022; Borelli et al., Reference Borelli, Cohen, Pettit, Normandin, Target, Fonagy and Ensink2019; Ensink et al., Reference Ensink, Begin, Normandin and Fonagy2017).

Various lines of research have substantiated the significance of parental mentalizing or reflective functioning – a caregiver’s ability to reflect on their own internal mental experiences as well as those of their child – in forecasting developmental outcomes (Luyten et al., Reference Luyten, Nijssens, Fonagy and Mayes2017; Sharp & Fonagy, Reference Sharp and Fonagy2008; Slade, Reference Slade2005; Zeegers et al., Reference Zeegers, Colonnesi, Stams and Meins2017). Findings from diverse fields, each with unique emphases and assessment methods, converge on this point. Meins (Reference Meins2013) and colleagues’ research has focused on the capacity for parental mind-mindedness, while Oppenheim et al. (Reference Oppenheim, Koren-Karie and Sagi2001) proposed the construct of parental insightfulness, and Slade (Reference Slade2005) coined the notion of parental reflective functioning. Cicchetti and colleagues’ studies in this context focused on the role of mental-state language or internal-state lexicon (Beeghly & Cicchetti, Reference Beeghly and Cicchetti1994; Brown et al., Reference Brown, Ng, Lisle, Koenig, Sannes, Rogosch and Cicchetti2023).

Parental mentalizing represents a relationship-specific manifestation of a more general capacity for mentalizing. It is thought to foster the development of secure attachment, the child’s own capacity for reflective functioning, and, as noted, a climate conducive to the development of epistemic trust, adaptive emotion regulation, and positive interpersonal functioning. Although parenting practices may vary across cultures, their essential role in the development of mentalizing seems to be a universal phenomenon. A unique human trait appears to be our tendency to create narratives or stories about our intentionality or mental state language. The belief that another understands us or shares our narrative, or at least that we are aware of, is likely to lead to the establishment of the we-mode, which facilitates learning from others. The crucial factor is the recognition of oneself in another. Of course, the self as imagined may be significantly altered by the desire to identify, the propensity for mimicry, the innate tendency for synchrony, and might not initially be an accurate representation. Nonetheless, if the narrated imagined self aligns with the image of the self in the mind of the other, an identification or match occurs, enabling social learning and the merging of minds which is manifested in synchrony, a type of co-regulation between infants and their caregivers, through which infants learn emotion management strategies from interactions with caregivers (Endevelt-Shapira & Feldman, Reference Endevelt-Shapira and Feldman2023; Feldman, Reference Feldman2017). Taken together, these findings further support the emphasis on the agentive self in recent views on personality and personality development (Sharp & Wall, Reference Sharp and Wall2021) and thus provide promising avenues for further research concerning the role of the closely associated human capacities for meaning-making, agency, and social learning in psychological development.

Research on large language models, together with another newly emerging field, that of developmental robotics (Cangelosi & Schlesinger, Reference Cangelosi and Schlesinger2018), may be able to help us better understand the role of (parental) mentalizing and mental-state language more generally in creating the feeling of being understood and the feelings of competency and agency this seems to engender. At the same time, developmental psychopathology may also be helpful in improving current large language models by examining their underlying assumptions (Frank, Reference Frank2023).

The need to improve prevention and intervention strategies

Over the past decades, there has been a significant increase in the development and empirical assessment of prevention and intervention strategies for psychological disorders and issues in children and young people. However, similar to the situation in adults (Cuijpers, Reference Cuijpers2019; Leichsenring et al., Reference Leichsenring, Steinert, Rabung and Ioannidis2022), there remains considerable room to enhance these strategies for children and young people. The finding that the effectiveness of psychological interventions for children and young people has on average not improved despite the past five decades of research is particularly concerning (Weisz et al., Reference Weisz, Kuppens, Ng, Eckshtain, Ugueto, Vaughn-Coaxum, Jensen-Doss, Hawley, Krumholz Marchette, Chu, Weersing and Fordwood2017, Reference Weisz, Kuppens, Ng, Vaughn-Coaxum, Ugueto, Eckshtain and Corteselli2019). Additionally, the implementation of evidence-based intervention strategies in routine clinical care is significantly behind scientific advancements, and many children and young people, along with their caregivers, especially those in socioeconomically challenging situations, have limited or no access to effective psychological care (Fonagy & Luyten, Reference Fonagy and Luyten2021; Kazdin & Blase, Reference Kazdin and Blase2011; Kazdin, Reference Kazdin2011; Weisz et al., Reference Weisz, Kuppens, Ng, Eckshtain, Ugueto, Vaughn-Coaxum, Jensen-Doss, Hawley, Krumholz Marchette, Chu, Weersing and Fordwood2017).

Looking ahead, there is likely to be a shift from specific school-based interventions toward more comprehensive and integrative mechanism-based interventions. In a recent extensive study involving 348 treatment-control comparisons from 263 randomized studies in young people, for example, the impact of five empirically supported principles of change was examined. The principles are simple: reducing arousal, make desirable behavior rewarding, changing distorted cognitions, skill building in problem solving, and encouraging activities that counter unhelpful behavior. The results indicated that treatments integrating all five of these principles had effects approximately twice as large as those based on fewer principles (Fitzpatrick et al., Reference Fitzpatrick, Cho, Venturo-Conerly, Ugueto, Ng and Weisz2022). These findings align with research suggesting that modular, transdiagnostic interventions could be more effective than disorder-specific approaches (Evans et al., Reference Evans, Weisz, Carvalho, Garibaldi, Bearman and Chorpita2020).

Improving social support, and increasing the ability of children, young people and their families to benefit from their social environment in particular, may be a final common pathway to positive mental health, as well as a result of processes that enhance aspects of mental health, such as self-esteem and relationship-recruiting capacities. Those who endure prolonged social support deficits and loneliness often develop epistemic mistrust and inappropriate epistemic credulity, which, instead of fostering social engagement, trigger fear-based responses to situations, leading to a further breakdown of trust in relationships and increased isolation (Cacioppo et al., Reference Cacioppo, Capitanio and Cacioppo2014; Cacioppo, Cacioppo et all., Reference Cacioppo, Cacioppo, Capitanio and Cole2015; Cacioppo, Grippo, et al., Reference Cacioppo, Grippo, London, Goossens and Cacioppo2015; Smith & Pollak, Reference Smith and Pollak2021b). A meta-analysis by Skeen and colleagues (Skeen et al., Reference Skeen, Laurenzi, Gordon, du Toit, Tomlinson, Dua, Fleischmann, Kohl, Ross, Servili, Brand, Dowdall, Lund, van der Westhuizen, Carvajal-Aguirre, Eriksson de Carvalho and Melendez-Torres2019) of the active components of universal interventions to improve adolescent mental health, identified the development of adolescents’ social skills to support improved interpersonal relationships as crucial in enhancing their mental health. These findings align with our view of the role of social support. We believe this process is bidirectional: providing skills to engage in social relationships also increases the capacity for mentalizing and discerning personally relevant social communication (i.e., epistemic trust). In several studies, interventions aimed at rebuilding such relationships, transforming them from those based on power imbalances to reciprocal ones, have enabled the establishment of trust (Bauer et al., Reference Bauer, Stevens, Purtscheller, Knapp, Fonagy, Evans-Lacko and Paulsubmitted).

These findings are consistent with our view that all effective psychotherapeutic interventions involve changes in social learning across three hypothetical communication systems (Fonagy, Luyten, et al., Reference Fonagy, Luyten and Allison2015; Luyten et al., Reference Luyten, Campbell, Allison and Fonagy2020). Communication system 1 focuses on reducing epistemic mistrust by presenting a model of the mind that instills a sense of recognition and independence in the patient. We concur with the viewpoint that prevention and intervention strategies should maximize the use of various empirically supported principles of change, fostering feelings of significant mirroring, and thereby enhancing the patient’s sense of agency and autonomy and reducing arousal and threat. This differs from historical approaches that often rely on a limited number of these principles. The revival of agency in the patient is believed to reactivate communication system 2, promoting mentalizing and social learning through augmented epistemic trust and opening the individual’s mind to the possibility of lasting change in their understanding. Enhanced mentalizing and epistemic trust, in turn, lead to engagement with communication system 3, which involves reconnecting with the social world, allowing the patient to interact with their wider social environment in new ways. For individuals with a background of early adversity and deprivation, this treatment phase also includes interventions at the social environmental level, counteracting social thinning and aiding the patient in developing a more adaptive social context and interpersonal relationships. This theoretical model offers a transtheoretical, transdiagnostic, and developmental view of psychotherapeutic change, suggesting that similar processes and mechanisms are operative in both normal psychological development and psychological interventions.

While precision medicine approaches, which tailor treatment to the specific needs of patients, may enhance the effectiveness of therapeutic interventions within each of these three communication systems, considering the complexity of developmental trajectories discussed earlier in this paper, such approaches seem more akin to science fiction than an imminent reality. However, those of us working in this field need to continue investing in precision medicine techniques. For example, the success of attachment-based approaches, grounded in research using the Adult Attachment Interview (George et al., Reference George, Kaplan and Main1985), has been notable in predicting a broad range of developmental outcomes by analyzing only four parameters of an individual’s narrative as per Grice’s maxims (Reference Grice1989) (i.e., quantity, quality, relation, and manner).

As mentioned earlier, we must acknowledge that the effectiveness of psychosocial interventions for children and young people has not shown significant improvement in recent decades (Weisz et al., Reference Weisz, Kuppens, Ng, Vaughn-Coaxum, Ugueto, Eckshtain and Corteselli2019). Therefore, we have a pressing responsibility to enhance the efficacy of such interventions in the coming years. At the same time, we must acknowledge that psychosocial interventions might have reached their maximum effectiveness. In this context, the field needs to significantly expand prevention strategies. For example, population-attributable fractions of early adversity (the degree to which psychopathological outcomes could be reduced if early adversity were prevented) typically range from 20 to 50% (Dragioti et al., Reference Dragioti, Radua, Solmi, Arango, Oliver, Cortese, Jones, Il Shin, Correll and Fusar-Poli2022). Socioeconomic disparities have a similar impact on the prevalence of psychopathology and help-seeking behaviors (Evans-Lacko et al., Reference Evans-Lacko, Aguilar-Gaxiola, Al-Hamzawi, Alonso, Benjet, Bruffaerts, Chiu, Florescu, de Girolamo, Gureje, Haro, He, Hu, Karam, Kawakami, Lee, Lund, Kovess-Masfety, Levinson and Thornicroft2018; Lund et al., Reference Lund, Brooke-Sumner, Baingana, Baron, Breuer, Chandra, Haushofer, Herrman, Jordans, Kieling, Medina-Mora, Morgan, Omigbodun, Tol, Patel and Saxena2018). The remarkable effectiveness of prevention strategies in reducing the prevalence of somatic diseases has not been matched by equivalent success in the realm of psychological disorders. Despite considerable advances in understanding the crucial role of secure attachment relationships and an emotionally supportive environment in child development, it is surprising that many children still grow up in environments lacking these elements. For instance, while the impacts of physical and sexual maltreatment are well recognized and declining in prevalence, the comparably serious consequences of verbal abuse receive less attention and its frequency is likely increasing (Li et al., Reference Li, Dube, Singh, Khamisa, Fiorini and Fonagy2022). It is notable that many parents and children are often more knowledgeable about their cellphones than about their own and each other’s minds.