'Pseudohallucination' is used in the classification of non-psychotic perceptual disorders. This review article describes the history of the concept and investigates whether pseudohallucinations can be differentiated from related psychopathological symptoms, such as hallucinations, reexperiencing and dissociative phenomena. It is concluded that the concept of pseudohallucinations and related concepts are clinically ambiguous and appear to have low discriminant validity. Most likely, the concept is placed on a continuum that includes perceptual disorders, reexperiencing, (dissociative) imagery and normal processes of thought and memory; the various concepts are considered to overlap. Recommendations are made regarding the specification of elements of this continuum. The term non-psychotic hallucinations is preferred to pseudohallucinations.