Which of the following best describes excoriation disorder?

A. Hallucinations are a core positive symptom of schizophrenia and involve false sensory perceptions without an external stimulus (e.g., hearing voices, seeing things that are not there). According to the DSM-5, hallucinations are one of the three essential symptoms that must be present for a diagnosis.

B. Delusions are fixed, false beliefs that persist despite evidence to the contrary (e.g., persecutory delusions, grandiose delusions). Delusions are a hallmark symptom of schizophrenia and are required as a diagnostic criterion if present.

C. Disorganized speech reflects disorganized thinking, a key symptom of schizophrenia. It includes incoherence, tangentiality, and word salad, demonstrating the cognitive dysfunction associated with the disorder. If disorganized speech is present, it fulfils one of the primary diagnostic criteria.

D. Negative symptoms such as avolition, anhedonia, alogia, and flat affect, are common in schizophrenia but are not required for diagnosis. According to the DSM-5, at least one of the following three symptoms hallucinations, delusions, or disorganized speech must be present to meet the diagnostic criteria for schizophrenia.

A. False belief that someone is following. This describes a persecutory delusion, a type of false, fixed belief where a person is convinced they are being watched, followed, or harmed despite no evidence. Delusions are thought disturbances, whereas illusions involve misinterpretations of sensory stimuli.

B. Misinterpretation of real experience. An illusion occurs when a person misperceives an actual external stimulus. For example, seeing a coat hanging in a dark room and mistaking it for a person. Unlike hallucinations, illusions are based on real sensory input that is distorted or misinterpreted.

C. Feeling things that are not there. This describes a tactile hallucination, where a person experiences false sensory perceptions of touch, such as bugs crawling on the skin. Tactile hallucinations are commonly seen in substance withdrawal (e.g., alcohol withdrawal, cocaine intoxication) and psychotic disorders.

D. Hearing voices that are not there. This describes an auditory hallucination, the most common type of hallucination in schizophrenia and other psychotic disorders. Unlike illusions, hallucinations occur without any external stimulus and are perceived as real by the affected individual.