Phantosmia

Phantosmia is an olfactory hallucination. A hallucination is the sensory perception of something with no basis in reality, as opposed to an olfactory illusion, which is a misinterpretation of a physical stimulus; in the case of an odor it is known as parosmia. Phantosmia is the perception of a smell in the complete absence of any physical odor. The perceived odor can range from pleasant to disgusting. Although the causes of phantosmia are uncertain, it often occurs with neurological and psychological disorders such as schizophrenia, mood disorders, Parkinsons disease, epilepsy, neuroblastoma, and frequent migraines.