Subtypes of paranoia in a nonclinical sample

Previous research has proposed that there may be subtypes of paranoia with different patterns of performance on symptom and clinical measures. However, there has been little empirical examination of whether distinct subtypes actually exist. Recent research has suggested that paranoia can be found in normal individuals and exists on a continuum. Thus, it is possible that evidence for subtypes of paranoia can be derived from nonclinical samples.

From a total of 723 participants, we identified 114 college students who showed elevated levels of paranoia as determined by two measures of paranoid ideation. The remaining sample of 609 persons served as the nonparanoid control group. All participants completed measures of depression, self-esteem, and social anxiety. Scores from the high subclinical group was subjected to cluster analysis to derive homogeneous subtypes. Participants also completed a measure of attributional style, the IPSAQ, which was used to validate the subtypes and was not used in the cluster analysis.

Based on the cluster analysis, three subtypes were derived. Each subtype showed a different pattern of scores on measures of depression, self-esteem, and anxiety. There were also additional differences on the externalising and personalising bias scores from the IPSAQ between the subtypes.

We conclude that there is preliminary evidence for the presence of subtypes among nonclinical samples and discuss the patterns of performance in relation to previous research on subtypes of paranoia. The implications of these subtypes for the study of paranoia are discussed.