Do you have to be mad to believe in conspiracy theories? Personality disorders and conspiracy theories.

This study explored the relationship between belief in conspiracy theories and the personality disorders. A sample of 475 British adults, aged around 30 years, completed measures of Belief in Conspiracy Theories (CTs) and the Personality Disorders (PDs), as well as the SAPAS, a short intelligence test and two self-evaluations. Belief in CTs was correlated with nearly all PDs, as well as the three established higher order clusters (A: odd and eccentric; B: dramatic and emotional; C: anxious). A series of stepwise multiple regressions were computed. A final regression showed five of the variables (education, intelligence, Cluster A, B, and C) were significant, which indicated that less well-educated and less intelligent participants, scoring higher on two PD clusters (Cluster A and B) but lower on Cluster C, believed more in the CTs. Implications of the study for understanding the origin of CTs is discussed. Limitations of the study, particularly the sample and measures used, are acknowledged.