What is the definition of a hallucination?

A hallucination is defined as a sensory experience of something that does not exist outside the mind. This definition captures the essence of hallucinations, which can involve any of the senses: seeing something that isn’t present (visual hallucinations), hearing sounds that aren’t there (auditory hallucinations), or even feeling sensations like bugs crawling on the skin (tactile hallucinations). It is crucial to note that these experiences occur without real external stimuli, and they can be a symptom of various psychological or neurological conditions, such as schizophrenia or severe depression.

The other options refer to different psychological phenomena. Emotional responses to external stimuli involve reactions to real events or perceptions, which do not fit the concept of hallucinations. Vivid dreams that occur during sleep do not constitute hallucinations, as they happen during a different state of consciousness and are typically not experienced in the same way as waking hallucinations. Lastly, while a mental condition characterized by delusions may overlap with conditions causing hallucinations, delusions themselves are fixed false beliefs rather than sensory experiences. Thus, the correct definition emphasizes the sensory nature and lack of external reality associated with hallucinations.