Which of these is an irrational suspicion or mistrust of others?

Paranoia is an instinct or thought process believed to be heavily influenced by anxiety or fear, often to the point of delusion and irrationality. Paranoid thinking typically includes persecutory, or beliefs of conspiracy concerning a perceived threat towards oneself. Paranoia is distinct from phobias, which also involve irrational fear, but usually no blame.

Making false accusations and the general distrust of other people also frequently accompany paranoia. For example, an incident most people would view as an accident or coincidence, a paranoid person might believe was intentional. Paranoia is a central symptom of psychosis.

A common symptom of paranoia is the attribution bias. These individuals typically have a biased perception of reality, often exhibiting more hostile beliefs. A paranoid person may view someone else's accidental behavior as though it is with intent or threatening.

An investigation of a non-clinical paranoid population found that feeling powerless and depressed, isolating oneself, and relinquishing activities are characteristics that could be associated with those exhibiting more frequent paranoia. Some scientists have created different subtypes for the various symptoms of paranoia including erotic, persecutory, litigious, and exalted.