Conspiracy theories accusing specific groups of secret malevolent actions can foster a perception of the world as a dangerous place. In our research, we contend that both adherence and exposure to conspiracy beliefs can serve as a potential cause of certain psychological problems in the form of paranoid thoughts. This hypothesis was tested in three studies conducted among Polish and British participants. In Study 1 (longitudinal, N = 603), we found that conspiracy beliefs exerted a positive overtime effect on paranoid thoughts. Experimental studies 2 (N = 384) and 3 (N = 445), showed that being exposed to conspiracy theories (vs. control stimuli) heightened paranoid thoughts. In Study 3, we proposed a potential mechanism explaining this effect, according to which exposure to conspiracies increased paranoid thoughts via only negative intense emotions. Our work adds to the discussion on the consequences of conspiracy beliefs and has implications for mental health research, underlining the importance of designing interventions limiting the adverse effects of conspiracy beliefs.