Personality Disorders as Collections of Traits

This chapter argues that personality disorders can and should be understood as collections of basic personality traits from a general model of personality, namely the five-factor model (FFM). It reviews evidence for the convergence of FFM personality disorder profiles across multiple approaches—expert ratings (i.e., researchers and clinicians) and empirical relations. It discusses how to score the personality disorders from the FFM and provides evidence for the convergent, discriminant, and construct validity of this approach. The chapter also demonstrates how the new alternative model for personality disorders can be embedded within the more established and robust FFM literature.

The Current State of Personality Disorders Through the Lens of PDTRT

This chapter examines recent trends in personality disorder research as they appear in one of the top personality disorder journals—Personality Disorders: Theory, Research, and Treatment (PDTRT). The chapter provides an overview of the history of PDTRT, as well as describes the types of submissions and manuscripts published in the journal over the last 5 years. It also reports on research trends over that time period, noting increasing interest in the alternative model for personality disorders, the surfeit of research in borderline personality disorder and psychopathy, the increasing use of dimensional versus categorical approaches, the use of nonclinical samples, and the extension of personality disorder traits to younger populations.

Personality as Adaptation

This chapter examines personality in nonhuman primates where personality is seen as a dynamic, whole-organism phenomenon. Whereas in humans, the concept of personality is applied to persisting differences between individuals, in the world of animal biology, it is a concept that also describes species differences in adaptation to the environment, as well as population differences within the same species. The idea that personality reflects adaptation—at the species, population, and individual levels—is discussed from comparative/ecological, developmental, and evolutionary perspectives. The evidence that personality reflects adaptation is then used to discuss the existence, and persistence, of personality disorders in humans. The authors conclude that a broader, comparative perspective on the phenomenon of personality can provide novel ideas about what personality is, how it develops, and the value that it provides for organisms.

Molecular Trait Psychology

This chapter discusses the field of molecular psychology, which applies the tools of molecular biology (e.g., candidate gene studies, genome-wide association studies, optogenetics, genome editing) to the study of behavior and its underlying neural structures and functions. Specifically, the chapter reports on research that applies these tools to personality traits.

Personality Dysfunction and Trait Extremity

This chapter discusses the alternative model for personality disorders and its two criteria: impairment/dysfunction and personality disordered traits. Specifically, the chapter explores the distinctiveness between the two criteria. It notes that there is descriptive overlap between them, and it reports on a study examining the degree of empirical overlap. This overlap was reported to be extremely high, with correlations of .76 and .80 for self-report and interview ratings, respectively.

The Prevalence, Stability, and Impact of Personality Pathology in Later Life

This chapter notes that much research has examined the onset and stability of personality disorders through early adulthood with very little research examining personality disorders from middle adulthood to later life. The chapter outlines important issues and questions that should be addressed by studies concerned with personality pathology in older adults. It also reviews key findings from the St. Louis Personality and Aging Network (SPAN) Study.

Advances in Child Personality Research and Relevance for Personality Pathology

This chapter reviews the current state of research on defining and organizing normal-range personality traits in youth, the work defining and organizing maladaptive personality traits in youth, and evidence for the hierarchical organization of both normal-range and maladaptive early personality traits. Direct comparisons of work on younger populations to existing research on adults are made throughout the chapter, in order to facilitate an integrative life-span perspective of personality and personality pathology. These comparisons highlight areas in which there are important differences from work with adults that may be missed if the field neglects such a comprehensive, life-span view. Finally, implications of the work on child personality are drawn and important future directions for the field are highlighted.

The Principles of Personality Trait Development and Their Relation to Psychopathology

This chapter reviews five empirically supported principles of personality development: cumulative continuity (i.e., increasing trait stability across development), maturity (i.e., persons grow more socially adapted across development), social investment (i.e., commitment to socially conventional roles promotes maturity), corresponsiveness (i.e., persons choose environments that support their personalities), and plasticity (i.e., personality change can occur throughout the life course). Evidence for each of these principles is reviewed. Finally, implications for psychopathology are drawn.

The Interpersonal Situation

Interpersonal theory assumes that the most important expressions of personality and psychopathology occur in interpersonal situations between a self and an other, and that personality pathology is best understood in terms of patterned affective, behavioral, and self dysregulations as well as perceptual distortions in these interpersonal situations. This chapter presents an evidence-based model of interpersonal situations that is structured by dimensions relevant to the self (agency and communion), interpersonal behavior (dominance and warmth), and affect (valence and arousal). This dimensions in this structure can be assessed as relatively stable traits or as dynamic processes. The ability of the interpersonal situation model to provide a useful heuristic model for testable clinical hypotheses is illustrated through a case study of David.

Using Basic Personality Process Models to Inform the Personality Disorders

This chapter argues that models articulating the processes underlying normal personality traits, even more so than the structure of normal traits, may help to inform research on personality disorders (PDs). It first describes whole trait theory as a model of normal traits that focuses on process at the same time that it is based on normal personality structure. The chapter then shows how this model makes an easy translation to process models of borderline personality disorder, thereby forming a connection between normal personality and pathological personality at a process level. The resulting general model of borderline personality disorder suggests viewing PD symptoms as distinct, momentary events rather than as stable, enduring features of people. It argues that etiological theorizing should include the proximal mechanisms that lead to temporally bounded symptoms. For example, relationship instability is seen not as a feature of the person but as an event that flares up and then fades repeatedly, in response to events and interpretations of those events. Accumulating evidence in support of this model is described. A model connecting normal personality trait processes to pathological personality processes may strengthen the connection between normal personality and pathological personality more firmly.