Delusions and hallucinations are thought to be caused by excess binding of dopamine to which receptors?

Delusions and hallucinations, particularly in the context of psychotic disorders such as schizophrenia, are indeed associated with the overactivity of dopamine in the brain, specifically through binding to D2 receptors. Research into the dopamine hypothesis of schizophrenia suggests that elevated levels of dopamine activity, particularly in certain brain pathways, contribute to the positive symptoms experienced by individuals, including delusions and hallucinations.

D2 receptors are densely located in various brain regions integral to the regulation of mood, cognition, and perception, such as the mesolimbic pathway. When dopamine binds excessively to these receptors, it can lead to the disruption of normal cognitive processing and perception, resulting in the emergence of psychotic symptoms. This understanding underpins the mechanism of action for many antipsychotic medications, which primarily function by antagonizing D2 receptors to reduce dopaminergic activity and alleviate these symptoms.

In contrast, while other subtypes like D1, D3, and D4 receptors have their roles in neurotransmission and may be involved in various psychiatric conditions, they do not play the pivotal role attributed to D2 receptors in the manifestation of delusions and hallucinations. Therefore, D2 receptors are specifically implicated in the psychopharmacological framework regarding the excess dopaminergic activity