Neuroticism Research Paper

1. Basic Aspects Of The Dimension

Personality traits can be ordered hierarchically, ranging from narrow lower-order characteristics to very broad higher-order dimensions. Neuroticism is one of a small number of general traits that comprise the highest level of this hierarchy. This trait represents individual differences in the extent to which a person experiences the world as threatening, problematic, and distressing (Watson et al. 1994). High scorers on this dimension experience various negative emotions (e.g., anxiety, depression, anger, guilt, shame) more frequently and intensely than low scorers. They report suffering from a wide variety of problems (including minor health problems) and generally blame themselves for these problems; because of this, they tend to feel inadequate and inferior. Neurotic individuals are both self-critical and excessively sensitive to criticism, and they easily feel slighted. They report elevated levels of stress in their lives, and indicate that they cope poorly with that stress. Finally, they tend to view the world with a negativistic bias, and so see threats, problems, and crises where others do not. In contrast, low scorers on this dimension are self-satisfied and view the world as benign; they report few problems, low levels of negative emotions, and little stress.

1.1 Historical Development Of The Concept

As noted earlier, a neuroticism-like dimension has been included in virtually every prominent trait model. For instance, Cattell included the higher-order dimension of Adjustment-vs.-Anxiety in his highly influential taxonomy of personality. However, the trait was given many different names by personality researchers, and it is noteworthy that most of the early labels emphasized the relaxed, self-satisfied end of the dimension. For instance, the trait was called ‘Emotional Control,’ and ‘Emotional Stability’ by Fiske and Guilford, respectively. Similarly, the dimension was usually labeled ‘Emotional Stability’ in the early literature on the ‘Big Five’ or ‘five-factor’ model of personality (Wiggins and Trapnell 1997). The term ‘neuroticism’ itself was first popularized in the 1950s by the influential English psychologist Hans Eysenck, who included a scale with that name in his Maudsley Personality Inventory.

This diversity of labels caused confusion in the field for several decades, because it was unclear whether all of these concepts actually reflected the same basic trait. However, integrative research in the 1980s clearly established that the same basic dimension was being assessed in all of these models (McCrae and Costa 1985, Watson and Clark 1984, Watson et al. 1994). This integration, in turn, stimulated an explosion of research on the trait during the late 1980s and 1990s. During this time, ‘neuroticism’ emerged as the preeminent label for the dimension, due in large part to a growing awareness of its prominent clinical correlates (which are discussed below).

1.2 Origins And Course Of The Trait

The genetic basis of neuroticism has been extensively investigated (Clark and Watson 1999). Heritability estimates based on twin studies typically fall in the 0.40 to 0.60 range, with a median value of approximately 0.50. It also should be noted, however, that heritability estimates decline significantly with age and are consistently lower in older respondents. The remaining variance can be attributed entirely to the unshared environment; indeed, the evidence overwhelmingly suggests that the common rearing environment (i.e., the effects of living together in the same household) exerts virtually no effect on the development of this trait. The nature of this genetic component has not yet been clearly established. The current thinking in the field, however, is that it gives rise to individual differences in sensitivity to painful, punishing, and stressful stimuli; that is, high scorers on the trait are innately disposed to show stronger adverse reactions to noxious and threatening stimuli. In support of this view, studies have shown that neurotic individuals report larger increases in negative emotion in response to unpleasant mood inductions. In light of this evidence, it is not surprising that neuroticism scores are strongly stable over time (see Clark and Watson 1999). Stability correlations typically fall in the 0.70 to 0.80 range over retest intervals of five to 10 years. Stability coefficients still exceed 0.60 over much longer time spans; Helson and Klohnen (1998), for instance, obtained a 25-year stability correlation of 0.65 in women assessed at ages 27 and 52. However, this stability is superimposed on a significant agerelated decline. Specifically, neuroticism scores peak in late adolescence and then begin a long, slow decline that continues at least into middle adulthood (Clark and Watson 1999, Helson and Klohnen 1998). After that, the evidence is less clear, but it appears that scores on the trait stabilize and show no further change. There also is a modest sex difference, with women scoring slightly higher on the trait than men.

2. Broader Significance Of The Trait

As stated previously, neuroticism is widely regarded to be the single most important trait of human personality. This view reflects the fact that this dimension has important correlates across a broad range of functioning. This section explores three particularly rich research areas: (a) psychopathology, (b) job and marital satisfaction, and (c) health.

2.1 Neuroticism And Psychopathology

Neuroticism has stronger, clearer, and broader associations with psychopathology than any other personality trait (Clark and Watson 1999, Mineka et al. 1998, Widiger et al. 1999). Elevated neuroticism has been linked to a wide array of clinical syndromes, including anxiety disorders, mood disorders, substance use disorders, somatoform disorders, eating disorders, personality and conduct disorders, and schizophrenia. Indeed, it is increasingly apparent that most psychological disorders are associated with elevated scores on this dimension. The breadth of these links is unsurprising, given that emotional distress is one of the defining criteria of both neuroticism and psychological disorder. Neuroticism is particularly strongly related to clinical syndromes that contain a prominent component of subjective distress. For instance, the trait has extremely strong associations with major depression, generalized anxiety disorder, and borderline personality disorder. These links are so strong, in fact, that syndromes such as generalized anxiety disorder and borderline personality disorder essentially may represent extremely high levels of neuroticism (Clark and Watson 1999, Widiger et al. 1999). In support of this argument, recent twin study evidence strongly suggests that neuroticism, generalized anxiety disorder, and major depression are genetically indistinguishable; in other words, they can all be traced to a single genetic diathesis that apparently reflects an underlying vulnerability to subjective distress and negative emotionality (Mineka et al. 1998). In contrast, neuroticism is more weakly related to disorders that are not centered on the experience of emotional distress. For instance, individuals with specific phobias (e.g., fear of spiders or other small animals) show only modest elevations on the trait (Mineka et al. 1998).

2.2 Neuroticism And Dissatisfaction

High scorers on this dimension report a pervasive dissatisfaction with themselves and the world around them. This dissatisfaction influences almost every aspect of their lives. For instance, numerous studies have shown that neurotic individuals report greater marital dissatisfaction and show greater instability (e.g., increased risk of divorce) in their relationships (Karney and Bradbury 1995). It is noteworthy that much of this evidence is longitudinal, demonstrating that neuroticism scores obtained early in a relationship predict its subsequent course. The most striking evidence along these lines was reported by Kelly and Conley (1987), who followed a large sample of couples from the mid-1930s through the early 1980s. Their results indicated that respondents who initially were high in neuroticism (assessed between 1936 and 1941) were more likely to become divorced over the course of the study. Moreover, neuroticism significantly predicted subsequent levels of marital dissatisfaction assessed in 1954–5 and 1981. Thus, the trait showed significant predictive power over a time span of more than 40 years.

Similarly, several studies have shown that high scorers on the trait report significantly greater job dissatisfaction (Judge et al. 1998). Again, much of the relevant evidence is longitudinal. Most notably, Staw et al. (1986) found that a neuroticism measure assessed in adolescence was a significant predictor of job satisfaction nearly 50 years later, even after controlling for objective differences in work conditions.

2.3 Neuroticism And Health

Throughout much of the twentieth century, the ‘psychosomatic hypothesis’—that is, the idea that chronically elevated levels of negative emotion eventually will lead to illness—was a dominant theoretical paradigm in behavioral medicine. Given that neurotic individuals report more frequent and intense episodes of negative emotion, it was widely assumed that neuroticism was a significant vulnerability factor for physical illness. Consistent with this assumption, neuroticism scales consistently show significant, moderate correlations with measures of physical symptoms and health complaints. Moreover, this association is quite broad, with neurotic individuals reporting increased levels of headaches, chest pain, dizziness, nausea, coughing, sneezing, congestion, and numerous other problems (see Watson and Pennebaker 1989).

However, research conducted during the 1970s and 1980s indicated that neuroticism was not strongly or consistently related to objective indicators of health status, such as health-related behaviors (e.g., number of physician visits for illness), biological markers (e.g., immune system functioning), and health outcomes (e.g., mortality rates). In other words, neuroticism is a much better predictor of subjective health complaints than it is of objective health status. Because of this, it is now widely recognized that neuroticism is an important nuisance factor that must be assessed and analyzed in health research.

3. Future Directions

Neuroticism clearly has important implications for almost every aspect of human functioning. However, researchers still know relatively little about how this trait actually works. How do innate genetic biological differences give rise to such striking individual differences in distress and dissatisfaction? What maladaptive cognitive processes and behavioral strategies contribute to the obvious misery of neurotic individuals, and can they be eliminated through psychological treatment? These questions will drive the next generation of research on neuroticism.

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