Current cognitive neuropsychology research points toward a two-factor approach to the cause of<unk> s. The first factor being the anomalous experience—often a neurological defect—which leads to the delusion, and the second factor being an impairment of the belief formation cognitive process. As an example of one of these first factors, several studies point toward Capgras delusion being the result of a disorder of the affect component of face perception. As a result, while the person can recognize their spouse (or other close relation) they do not feel the typical emotional reaction, and thus the spouse does not seem like the person they once knew. As studies have shown, these neurological defects are not enough on their own to cause delusional thinking. An additional second factor—a bias or impairment of the belief formation cognitive process—is likely required to solidify and maintain the delusion. This need for a second factor results in two factor theories to explain<unk> s - anomalous experience and some sort of underlying pathology of belief production. Since we do not currently have a solid cognitive model of the belief formation process, this second factor is still somewhat of an unknown, and some hypotheses regarding delusion formation don't posit a second factor as necessary. Some research has shown that delusional people are more prone to jumping to conclusions, and thus they would be more likely to take their anomalous experience as veridical and make snap judgments based on these experiences. Additionally, studies have shown that they are more prone to making errors due to matching bias—indicative of a tendency to try and confirm the rule. These two judgment biases help explain how delusion-prone people could grasp onto extreme delusions and be very resistant to change. Researchers claim this is enough to explain the delusional thinking. However, other researchers still argue that these biases are not enough to explain why they remain completely impervious to evidence over time. They believe that there must be some additional unknown neurological defect in the patient's belief system (probably in the right hemisphere).
Monothematic delusion
Homicidal ideation
Grandiose delusions
Mirrored-self misidentification
Intrusive thought
Cotard delusion
Morbid love
Obsessive love