Feeling close to others? Social cognitive mechanisms of intimacy in personality disorders

The level of personality functioning is at the core of the definition of personality disorders (PDs) in the alternative model of PDs (AMPD) of the DSM-5-TR [1]. It is defined by two domains, each comprising two sub-domains: self-functioning, which encompasses identity and self-direction, and interpersonal functioning, which includes intimacy and empathy. All these domains and sub-domains refer to complex and multifaceted constructs. In this editorial we will focus on intimacy as defined by the AMPD, which comprises three elements: first, the depth and duration of connection with others; second, one’s desire and capacity for closeness; and finally, the mutuality of regard reflected in interpersonal behaviour [1].

Definition of intimacy

The American Psychological Association (APA) defines intimacy as “an interpersonal state of extreme emotional closeness such that each party’s personal space can be entered by any of the other parties without causing discomfort to that person. Intimacy characterizes close, familiar, and usually affectionate or loving personal relationships and requires the parties to have a detailed knowledge or deep understanding of each other.” [2].

The conditions that must be met for intimacy to occur include reciprocal feelings of trust, emotional closeness between the partners, and self-disclosure, i.e., the ability to openly communicate thoughts and feelings with each other [3]. Similarly, the Intimacy Process Model (IPM) posits that the development of intimacy depends on repeated dyadic interactions characterized by self-disclosure by one partner and an understanding, validating and caring response from the other [4].

Intimacy is a significant factor in identity formation and adult development. It facilitates the consensual validation of personal worth by providing individuals with the opportunity to feel understood and accepted as they are within a relationship. Moreover, intimacy requires the capacity to form close affiliations and, thus, is a crucial factor in determining an individual’s satisfaction with social support [3].

In accordance with Erikson’s (1963) model of psychosocial development, this capacity to invest in close relationships undergoes significant intensification during the emerging adulthood period, when individuals develop the ability to share life interests and goals with others [5]. Consequently, intimacy represents both an individual intrapsychic developmental achievement, which predicts long-term health of relationships [6], and an interpersonal process, which involves the interaction between two individuals [4, 7].

The concept of intimacy encompasses a multitude of domains, including emotional, social, physical, intellectual, spiritual and recreational intimacy [8]. Olson suggested that intimate relationships with others emerge through the sharing of intimate experiences with another individual in a number of these domains [9]. As a result, intimate relationships can be diverse and can occur in different social contexts including romantic relationships, friendships and kinship [7, 8, 10, 11].

The definitions of intimacy already emphasise its state-like character, suggesting that the level of intimacy experienced within a relationship may fluctuate over time [12]. Although intimacy avoidance is defined as a personality trait, individuals experience frequent state-like fluctuation in the levels of intimacy as a result of an interpersonal process [13]. Furthermore, intimacy may vary between individuals depending, for example, on gender [14, 15], levels of trait self-esteem [16], phases within the life span [17] and culture [18, 19]. This highlights the necessity to consider variations in intimacy between relationships in different social domains as well as within the same relationship, when investigating alterations in intimacy.

Intimacy impairments in personality disorders

The DSM-5 AMPD highlights impairments of intimacy as a central diagnostic feature of PDs in general, but also emphasizes that these impairments might take quite different forms [1]. For example, for avoidant PD, impairments of intimacy arise from being reluctant “to get involved with people unless being certain of being liked” and “because of fear of being shamed or ridiculed.” [1]. In contrast, for borderline PD (BPD), difficulties with intimacy are characterised as having “intense, unstable, and conflicted close relationships, marked by mistrust, neediness, and anxious preoccupation with real or imagined abandonment.” [1]. The impairments in developing close relationships are assumed to stem from “mistrust and anxiety” for schizotypal PD, while in narcissistic PD “relationships [are] largely superficial and exist to serve self-esteem regulation; mutuality [is] constrained by little genuine interest in others’ experiences and predominance of a need for personal gain.” [1]. A different pattern has been described for obsessive compulsive PD with “relationships [being] seen as secondary to work and productivity; [and] rigidity and stubbornness negatively affect relationships with others.” [1].

All these characterisations imply that PDs may prevent individuals to feel close to others, while also suggesting that the underlying mechanisms and motivations might differ substantially. However, for psychosocial interventions to successfully influence the perception and evaluation of social relationships and modify individuals’ interaction behaviours in a beneficial manner, it is essential that the targeted constructs are precisely defined. The investigation of social cognitive functioning may provide a theoretical framework to evaluate the diverse mechanisms that may result in impairments of intimacy as a final common pathway across different PDs. This would facilitate the development of potential tailored foci of intervention.

Social cognitive information processing as a framework to investigate mechanism of impaired intimacy in PD

Based on the definition of the International Social Cognition Network, social cognition is an approach to understanding social psychological phenomena by investigating the cognitive processes that underlie them. “It covers the processes involved in the perception, judgment, and memory of social stimuli, [but also] the effects of social and affective factors on information processing, [as well as] the behavioral and interpersonal consequences of cognitive processes.” [20]. The investigation may focus on a range of analytical levels, including intrapersonal, interpersonal, intragroup, and intergroup processes.

The number of studies investigating social cognition in PDs has been on the rise during recent years. Most studies have focussed on BPD, examining clinical samples of patients, who meet the criteria for BPD as defined by established categorical classification systems, and samples from general or student populations using borderline personality features as a dimensional measure [21]. Nevertheless, studies employing the AMPD or even studies integrating AMPD and categorical approaches remain scarce. Furthermore, most experimental studies on social cognition have focussed on isolated social-cognitive processes such as the evaluation of discrete social stimuli. However, these processes may also be shaped by an individual’s expectations, beliefs, schemata or ‘priors’. This suggests that alterations in processing may not be indicative of a genuine impairment of the social cognitive processes, but rather of the influence of an individual’s latent mental structures, which are formed by social-affective experiences and interact with an individual’s specific biological predispositions [22–24]. The IPM has already emphasized such a complex interplay between social cognitive processes and multiple motivations and dispositions (i.e., an individual’s “interpretative filter”) during the formation of intimacy in dyadic interactions [4].

However, there is a paucity of studies that have sought to establish a differential link between alterations in specific social cognition processes and the diverse difficulties in intimacy associated with specific categories of PD or specific pathological personality traits of the AMPD.

Conclusions and implications for future research

In conclusion, the advancement of our understanding of impairments of intimacy in PDs and the refinement of interventions necessitate both a fine-grained delineation of impairments of intimacy and the implementation of carefully designed experimental approaches to elucidate the processes that may underlie impairments in this domain of personality functioning. The need of additional research is especially pressing, since qualitative studies have indicated that consumers and caregivers emphasize the importance of the quality of intimate relationships to facilitate personal recovery in PDs. This entails addressing the pervasive feelings of loneliness and strengthening the “capacity to love oneself and others” [25, 26]. The “practical”, daily difficulties in intimacy that are experienced by individuals with PDs constitute a burden not only for the affected individuals themselves, but also for their social environment. A deeper understanding of the specific mechanisms that underlie impaired intimacy might help to provide more tailored interventions and to deal with the interpersonal consequences of PDs for the individuals’ and societal well-being.

Author contributions

All authors participated in writing the manuscript and read and approved the final manuscript.

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