Also known as command hallucination. The term imperative hallucination is indebted to the Latin verb imperare, which means to command. It is used to denote a variant of the "verbal auditory hallucination, the content of which involves an incentive or command. Although less common, and underreported in the empirical literature, imperative hallucinations may also occur in the visual modality (involving a visually hallucinated written command, for example, or a command in hallucinated sign language) or in any of the other sensory modalities. Imperative hallucinations experienced in the visual modality are also referred to as visual command hallucinations. It is open to debate whether hallucinations consisting of a rudimentary message (such as the single word 'Yes,' or a perceived pat on the back), which are merely interpreted by the affected individual as a command (for example, "Yes, this is the person you should talk to"), should be allowed to count as imperative hallucinations proper. Reliable incidence and prevalence figures of imperative hallucinations are lacking. Among adult voice hearers with a psychiatric diagnosis, imperative hallucinations have been reported in 18-89% of cases. The perceived commands can involve anything from an invitation to perform a harmless or even beneficial act, to an instigation to physically violent behaviour.
References
Byrne, S., Birchwood, M., Trower, P.E., Meaden, A. (2006). A casebook of cognitive behaviour therapy for command hallucinations: A social rank theory approach. London: Routledge.
Erkwoh, R., Willmes, K., Eming-Erdmann, A., Kunert, H.J. (2002). Command hallucinations: Who obeys and who resists when? Psy-chopathology, 35, 272-279.
Dictionary of Hallucinations. J.D. Blom. 2010.