This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Which of the following is not a feature of hallucination: September2010 
Select and explain. 
A. It can occur in any sensory modality, B. It is independent of will of observer, C. It is defined as perception occurring without external stimulation, D. Always pathological
D: Always pathological
Answer: D: Always pathological 
Explanation: Ans. D: Always pathologicalA hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus.In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space. Hallucinations can occur in any sensory modality -- visual, auditory, olfactory, gustatory, tactile, proprioceptive, equilibrioceptive, nociceptive, thermoceptive and chronoceptive.