Organic Hallucinosis is a disorder of persistent or recurrent hallucinations, usually visual or auditory, that occur in clear consciousness and may or may not be recognized by the subject as such. Delusional elaboration of the hallucinations may occur, but delusions do not dominate the clinical picture; insight may be preserved. 
According to ICD-10 (F06.0), presence of persistent or recurrent hallucinations due to an underlying organic cause is required for the diagnosis of organic hallucinosis. It is important to rule out any major disturbance of consciousness, intelligence, memory, mood or thought.
These hallucinations can occur in any sensory modality but are usually visual (most common) or auditory in nature. These hallucinations can range from very simple and unformed, to very complex and well-organised. Usually the patients realise that the hallucinations are not real but sometimes there may be a delusional elaboration of hallucinations. 
1. Drugs: Hallucinogens ( LSD, psilocybin, mescaline), cocaine, cannabis, phencyclidine (PCP), levodopa, bromocriptine, amantadine, ephedrine, propranolol, pentazocine, methyl phenidate, imipramine, anticholinergics, bromide.
2. Alcohol: In alcoholic hallucinosis, auditory hallucinations are usually more common.
3. Sensory deprivation.
4. ‘Release’ hallucinations due to sensory pathway disease, e.g. bilateral cataracts, otosclerosis, optic neuritis.
6. Epilepsy: Complex partial seizures.
7. Intracranial space occupying lesions.
8. Temporal arteritis.
9. Brain stem lesions (peduncular hallucinosis). 
1. Treatment of the underlying cause, if treatable.
2. Symptomatic treatment with a low dose of an anti psychotic medication (such as Haloperidol, Risperidone and Olanzapine) may be needed.