The present study examined the incidence of paranoid ideation in a nonclinical population. A sample of 324 college students completed a questionnaire assessing their personal experiences of paranoia, with an emphasis on the cognitive, behavioral, and affective components of their experience. They also completed a general measure of paranoia in nonclinical samples, the Fenigstein and Vanable Paranoia Scale, and the Rosenberg Self-Esteem Scale. A total of 153 participants reported an experience of paranoia, which included a clear statement of planned intention to harm. This group scored significantly higher on the Paranoia Scale than those who reported no experience of paranoia. Furthermore, greater levels of paranoid ideation were associated with lower self-esteem. The present findings suggest that paranoia is a common human experience, and are consistent with the idea of continuity between normal and abnormal experience.
Dimensional views of adult psychopathology are widely accepted among psychologists (Claridge, 1997) and increasingly among psychiatrists (Van Os et al., 1999). These views propose a continuity between, on the one hand, either a clinical disorder or an individual symptom, and on the other hand, behaviors and experiences that appear to be their normal counterparts. Dimensional views are prominent in current thinking about psychosis, and schizophrenia in particular. In a seminal article, Meehl (1962) argued that there exists in the general population a predisposition to schizophrenia, schizotypy, which is an expression of a genetic vulnerability, schizotaxia. From this view, psychotic symptoms in those with a diagnosis of schizophrenia are seen as the severe expression of traits present in the general population, and in a subclinical population-that is, those with clear signs of psychopathology, but insufficient to warrant a diagnosis (Claridge, 1987). Researchers have found evidence of traits hypothesized to be signs of vulnerability to schizophrenia (i.e., schizotypy) in the normal population (Claridge and Broks, 1984;Peters et al., 1999;Raine, 1991).
In an important paper, Costello (1994) distinguishes two main versions of the dimensional view. The first, the phenomenological view, hypothesizes that the symptoms of psychopathology occur in less intense, persistent and debilitating, but not qualitatively different forms, in normal people (emphasis in original). The second, the vulnerability view, hypothesizes that though there may be qualitative differences between symptoms of psychopathology and their normal counterparts, the degree to which the person possesses the apparent normal counterparts of the symptoms of a particular disorder is an index of that person's vulnerability for the disorder (p. 391). This distinction between phenomenological versus vulnerability views has parallels with the distinction by Claridge (1994) between fully dimensional and quasidimensional views. From the fully dimensional viewpoint, traits are represented in personality as healthy diversity, whereas from the quasidimensional perspective, they are seen as attenuated psychotic symptoms.
At the level of individual symptoms, Strauss (1969) first proposed that delusions and hallucinations lie on continua functions with normal behavior. He further proposed that certain key dimensions determined position on a continuum: with delusions, for example, these included degree of conviction, distress, and preoccupation. Subsequent research shows that both delusions (e.g., Chadwick and Lowe, 1990;Van Os et al., 2000) and apparently normal counterparts to (e.g., Peters et al., 1999) do indeed vary on these dimensions. Yet, as Costello (1994) observes, by itself this type of data provides no direct support for either the phenomenological or vulnerability view of dimensionality.
Social psychological research has suggested that in milder forms, paranoid cognitions seem to be quite prevalent among normal people. Fenigstein and Vanable (1992) developed a reliable (alpha = .84) and valid Paranoia Scale for use in the general population. The mean total score on the Paranoia Scale (range, 20 to 100) was 42.7 (N = 581). Although the distribution of scores was clearly skewed toward the low end, each item was endorsed by a majority of participants as at least slightly self-descriptive. The authors thus concluded that the concept of paranoia should be broadened to include normal, everyday thought processes. Subsequently, Martin and Penn (2001) used the Paranoia Scale to examine the relationship between paranoid ideation and various clinical and social cognitive variables in a nonclinical sample. They found that higher paranoid ideation was associated with greater depressed mood, higher social anxiety, greater attention to public aspects of the self, and lower self-esteem.
The present study aims to research people's own experiences of paranoia along a number of cognitive, behavioral, and affective dimensions known to be important in clinical paranoia (Personal Experience of Paranoia Scale [PEPS]), and using the Fenigstein and Vanable (1992) Paranoia Scale. This research follows Muris et al. (1997), who asked college students to describe their personal ritualistic behavior, of the type seen in obsessive-compulsive disorder (Rassin et al., 1999, for an extension of this research). Examining the topography of subjective experience of apparent normal counterparts of symptoms, combined with use of validated general measures, provides a foundation for subsequent tests of the phenomenological dimensional view (Costello, 1994). In our research, we used perceived planned persecution by others as the defining attribute of persecutory delusions (Freeman and Garety, 2000). This was chosen in part as a means to distinguish paranoia from social anxiety.
Therefore, the aims of the present study were to (1) determine whether a sample of college students report idiosyncratic experiences of paranoia, (2) examine this experience along key dimensions, (3) report on the relationship between idiosyncratic experiences of paranoia with scores on the Fenigstein and Vanable measure, and (4) examine the relationship between self-esteem and paranoid ideation.