Temperament as a Unifying Basis for Personality and Psychopathology Lee Anna Clark University of Iowa Personality and psychopathology long have been viewed as related domains, but the precise nature of their relations remains unclear. Through most of the 20th century, they were studied as separate fields; within psychopathology, clinical syndromes were separated from personality disorders in 1980. This division led to the revelation of substantial overlap among disorders both within and across axes and to the joint study of normal and abnormal personality. The author reviews these literatures and proposes an integrative framework to explain personality–psychopathology relations: Three broad, innate tempera- ment dimensions—negative affectivity, positive affectivity, and disinhibition— differentiate through both biologically and environmentally based developmental processes into a hierarchical personality trait structure and, at their extremes, are risk factors (diatheses) for psychopathology, especially given adverse life experiences (stress). Keywords: temperament, psychopathology, personality, taxonomy, DSM–V The first model of personality–psychopathology relations may have been the doctrine of the four humors, attributed to Hip- pocrates and Galen (Maher & Maher, 1994). The balance of these four humors— blood (sanguis), phlegm, bile (choler), and black bile (melancholer)— determined one’s temperament: sanguine, phlegmatic, choleric, or melancholic, respectively. Temperament, in turn, determined vulnerability to illness, and a humoral imbal- ance led to physical or mental illness. Balance—and thus health— was restored by such techniques as bleeding and purging. With the advent of modern science, which in psychology began in the late 19th century, theories of personality–psychopathology relations were based on Darwinian concepts (Maher & Maher, 1994). One basic theme was that all types of mental illness reflected a general character deficiency that was genetically based, and the specific forms of which reflected biological and/or per- sonal development. Freud’s well-known theory of the stages of character development, each with its associated psychopathology, is the most elaborate and influential of these views. In the early 20th century, Kraepelin posited that personality disorders were formes frustes of the major psychoses. Kretschmer went a step further, hypothesizing a single continuum from per- sonality (schizothyme) through personality disorder (schizoid) to clinical syndrome (schizophrenia; Livesley, Schroeder, Jackson, & Jang, 1994). Interestingly, Pavlovian conditioning theorists reju- venated the ancient four-humoral theory, substituting variation in neuronal responses for the strength and balance of humors (Maher & Maher, 1994), and Eysenck explicitly related his three-factor personality model to Pavlovian concepts. Whereas Eysenck’s di- mensions still play a major role in the field, the link to conditioning theories, for the most part, does not. This precis suggests that personality and psychopathology have been studied in relation to each other since antiquity, but that is only half the story. The other half is their division, both between psychiatry (with its major focus on abnormal processes) and psy- chology (which generally emphasizes the study of normal func- tioning) and also within each field. One sign of the split within psychology was the separation in 1965 of the Journal of Abnormal and Social Psychology into the Journal of Abnormal Psychology and the Journal of Personality and Social Psychology. The Advent of the DSM: An Atheoretical Model In mid-20th century, psychiatry systematized its accumulated knowledge of psychopathology in the Diagnostic and Statistical Manual of Mental Disorders (DSM–I, DSM–II; American Psychi- atric Association, 1952, 1968). In these DSMs, personality pathol- ogy was considered alongside other disorders with little attention to their potential interrelations. However, with the advent of DSM– III (American Psychiatric Association, 1980), personality disor- ders were given their own “Axis II,” which reopened the door for the systematic study of the two domains in relation to each other. The DSMs were intended as descriptive documents to aid both research and treatment planning. Whereas prevailing theories no doubt influenced each of the DSMs, theory per se was not a guiding principle in their development, and DSM–III explicitly declared its atheoretical intent. However, the creation of separate axes clearly indicated that personality disorders were considered a distinct type of psychopathology, which also invited study of their interrelation. A notable phenomenon of the successive DSMs was the increase in diagnoses, as well as in subtypes and specifiers to address within-diagnosis heterogeneity (Watson, 2003). Some of the diag- nostic increase was due to new disorders (e.g., cyclothymia), but a substantial proportion resulted from subdivison (e.g., bipolar dis- order into Bipolar I and Bipolar II disorders). These changes also were based largely on descriptive studies rather than theory-driven research. Virtually without offering either a theoretical rationale or em- pirical justification, DSM–III included hierarchical exclusion rules Correspondence concerning this article should be addressed to Lee Anna Clark, Department of Psychology, University of Iowa, 111 Jessup Hall, Iowa City, IA 52242-1316. E-mail: la-clark@uiowa.edu Journal of Abnormal Psychology Copyright 2005 by the American Psychological Association 2005, Vol. 114, No. 4, 505–521 0021-843X/05/$12.00 DOI: 10.1037/0021-843X.114.4.505 505