Hallucinations are

a. sensory experiences with no basis in reality

b. only seen in schizophrenia

c. necessary for a diagnosis of schizophrenia

d. disturbances in the content of thought

a. sensory experiences with no basis in reality

Explanation:

Hallucinations are sensations that appear to be real but are created within the mind. Examples include seeing things that are not there, hearing voices or other sounds, experiencing body sensations like crawling feelings on the skin, or smelling odors that are not there.

Answer: Hallucinations are: sensory experiences with no basis in reality.

Explanation: Hallucinations can be defined as sensory perception of something that does not exist, often arising from disorder of the nervous system, (as in psychosis of chronic alcoholism, usually due to alcohol withdrawal, which can be fatal); a delusion. Hallucinations involve hearing, seeing, feeling, smelling, or even tasting things that are not real.