Mood, Personality, and Personality Disorder

The important role of affect or mood in personality has come to be recognized increasingly in recent years, with temperament supplying the conceptual link between mood and personality. Indeed, the very term temperament implies both emotionality and personality. Temperamental theories of personality can be traced back to the ancient Greek physician Hippocrates, who proposed that an excess of each of four “humours” was associated with a different personality type which, in turn, were each defined in terms of a characteristic emotional style. Thus, the sanguine or cheerful, active personality reflected an excess of blood; the melancholic or gloomy personality reflected an excess of black bile; choleric or angry, violent types had an excess of yellow bile; and an excess of phlegm was associated with the phlegmatic or calm, passive personality.

According to modern views, two aspects of the ancient Greek formulation are important. First is the idea that biological factors underlie observable personality characteristics. Rather than humours, researchers today investigate, for example, serotonin deficits, hyperresponsivity of the noradrenergic system, or dysfunction in the mesolimbic dopaminergic pathways. Nevertheless, the recognition that behavior is—at least in part—a function of physical characteristics was a remarkable insight. Second, the ancient Greeks also recognized that a core and defining feature of different personalities was emotional, and on this point their typology was humblmgly similar to the ideas of modern researchers. As I describe in more detail later, neuroticism—emotional stability and intro-version-extraversion are two broad trait dimensions that have emerged repeatedly in modern studies of personality. figure 9-1 overlays the four Greek temperaments on Eysenck's version of these two dimensions of personality (Eysenck & Rachman, 1965). The sanguine personality is stable and extraverted, the choleric is unstable and extraverted, the melancholic is unstable and introverted, and the phlegmatic is stable and introverted.

There are two critical limitations to this striking, but nevertheless simplistic, matching. First, although it strongly suggests connections among emotion, temperament,

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and personality, it offers no explanation for these connections. To use the language of behavior genetics, this structural model describes the phenotypes but does not elucidate the genotypes. A second and related limitation is that the personality dimensions of introversion-extraversion and neuroticism-emotional stability are only partly emotional. For example, anxious and excitable are emotional components of neuroticism and extraversion, respectively, but talkative and thoughtful do not seem to be primarily emotional. So the structural model, by itself, does not provide a fundamental understanding of how these various concepts are connected. Theoretical understanding of the domain is not totally lacking, however. Indeed, a great deal of progress has been made since the 1970s. In the next section, I provide an initial theoretical context for the integration of several disparate threads.