Hallucination Vs Delusion – What’s the difference?

Hallucinations and Delusions, both are predominant symptoms of Psychosis. They both can overlap and they do in most of the cases of Schizophrenia. However, there is significant difference in symptomatology in both of them.

What is hallucination?

Hallucination is false perception in the absence of external stimulus. Hallucinations are generally indications of significant psychiatric disorder. They can be described in terms of complexity and sensory modality.

What is delusion?

Delusion is false, firm, fixed belief that is firmly held on inadequate grounds and patient continues to believe it despite giving evidence to the contrary. It is not influenced by person’s educational, cultural and religious background. 

What are the types of hallucinations?

The term elementary hallucination refers to experiences like banging, whistles, flash of light etc. While complex hallucination refers to hearing of voices or music, seeing faces etc.

Auditory hallucinations are experiences as noises, music or voices of a person/persons. Voices are heard clearly or indistinctly. When the person hears his own voice, its known as first person auditory hallucination. Some voices talk to a person directly, called as second person hallucinations. Voices even can talk to one another, called as third person hallucination. In schizophrenia, sometimes voices seem to give instructions to the patient, called as command hallucinations.

Visual hallucinations are experienced as seeing someone or seeing a scene which is experiences only by the patient. Images or visuals can be blurry or crystal clear as mentioned by the patient. Sometimes a shadow like figure/ghosts are seen in conversion disorder.

Olfactory and gustatory hallucinations are experienced as unpleasant smell or taste.

Tactile hallucinations may be experienced as sensations of being touched, pricked or strangled. Sometimes patient complaints as insects/worms crawling under the skin.

What are the types of delusion?

Primary delusion is one that appear suddenly and with full conviction without any psychological event leading up to it. For example, a patient suffering from schizophrenia suddenly start believing that he is changing sex.

Secondary delusions are derived mainly from a previous morbid experience. For example, someone who is hearing voices start believe that he is being followed. Or a depressed individual starts thinking that he is worthless.

Persecutory delusions, are concerned for group of persons/organization that are thought to be trying to inflict a harm on the patient. Such delusions can occur in schizophrenia, delusional disorder or bipolar disorder. A person thinks that someone follows him, keeps track of him through cameras or someone is coming to kill him.

Grandiose delusions, commonly occur in manic episode of bipolar disorder, wherein a person consider himself to be a special person with unusual abilities which no other person possess.

Delusion of guilt, are found most often in depression where there is an inappropriate guilt associated with the past and bring shame upon the patient. Patient blames himself for untoward consequences in the family.

Bizarre delusions, are delusions with highly improbable content (“I have been controlled by aliens who are communicating via birds “)

What is the treatment for hallucination and delusion?

In order to treat hallucination and delusion, first its very important to make a diagnosis in which these symptoms are showing. Treating the main disorder itself treats the underlying hallucination and delusions. Antipsychotic medicines are preferred molecules for such symptoms. If there is underlying depression or bipolar disorder or substance use, it should be treated accordingly.