The document outlines the differences between hallucinations and delusions, defining hallucinations as sensory perceptions without external stimuli and delusions as fixed false beliefs. It provides epidemiological data on prevalence and incidence rates in different populations, as well as diagnostic criteria from DSM-5 and ICD-11. Treatment options are discussed, including psychotherapy and antipsychotic medications, and the document notes that hallucinations can occur in the general population without indicating mental illness.

1. D E L U S I O N
H A L L U C I N AT I O N

2. P A R A C U S I S
• A hallucination is a perception in the
absence of an external stimulus that has the
compelling sense of reality.
• Maybe vivid and convincing
• Hallucination can occur in any sensory
modality
1. Visual
2. Auditory
3. Olfactory
4. Gustatory
5. Tactile

3. D E L U S I O N
• A delusion is a false fixed belief that is not amenable to change in light of
conflicting evidence. As a pathology, it is distinct from a belief based on false or
incomplete information, confabulation, dogma, illusion, hallucination, or some
other misleading effects of perception, as individuals with those beliefs are able
to change or readjust their beliefs upon reviewing the evidence.
• The main difference between hallucinations and delusions is that hallucinations
revolve around senses and delusions center on beliefs. Therefore, a
hallucination includes seeing, hearing, tasting, smelling, or feeling something
that isn't there.

4. E P I D E M I O L O G Y
Hallucinations:
• Prevalence:
1. General population: 1.4% to 4.6% (lifetime prevalence)
2. Psychiatric disorders: 10% to 70% (depending on
diagnosis)
3. Neurological disorders: 10% to 50% (depending on
diagnosis)
• Incidence:
1. First-episode psychosis: 1.2 to 2.5 per 1,000 person-years
2. Schizophrenia: 1.1 to 2.1 per 1,000 person-years
Delusions:
• Prevalence:
1. General population: 0.5% to 2.5% (lifetime prevalence)
2. Psychiatric disorders: 20% to 80% (depending on diagnosis)
3. Neurological disorders: 10% to 40% (depending on
diagnosis)
• Incidence:
1. First-episode psychosis: 1.5 to 3.5 per 1,000 person-years
2. Schizophrenia: 1.3 to 2.5 per 1,000 person-years

5. D I A G N O S T I C C R I T E R I A
• DSM-5
1. Schizophrenia (295.10-295.34)
2. Schizophreniform Disorder (295.40)
3. Schizoaffective Disorder (295.70)
4. Brief Psychotic Disorder (298.8)
5. Major Depressive Disorder with Psychotic Features (296.34)
6. Bipolar Disorder with Psychotic Features (296.44)
• ICD-11
1. Schizophrenia (6A20-6A24)
2. Other primary psychotic disorders (6A25-6A28)
3. Mood disorders with psychotic symptoms (6A40-6A44)
4. Organic or symptomatic mental disorders (6B00-6B1Z)

6. D U R AT I O N
Hallucinations
• Brief: seconds to minutes (e.g., in acute stress reactions)
• Episodic: recurring, minutes to hours (e.g., in substance-induced psychosis)
• Persistent: ongoing, hours to days (e.g., in schizophrenia)
• Chronic: continuous, weeks to months (e.g., in treatment-resistant schizophrenia)
Delusions
• Brief: days to weeks (e.g., in brief psychotic disorder)
• Episodic: recurring, weeks to months (e.g., in schizoaffective disorder)
• Persistent: ongoing, months to years (e.g., in schizophrenia)
• Chronic: continuous, years or more (e.g., in treatment-resistant schizophrenia)

7. T R E AT M E N T & P R O G N O S I S
• Psychotherapy (Cognitive behavioral therapy, Metacognitive therapy) in conjunction with
antipsychotic medication is the most effective form of treatment for delusion.
• Atypical - Risperidone, clozapine, quetiapine, ziprasidone and olanzapine.
• Buterophenones - Haloperidole.
• People who experience hallucinations do not necessarily suffer from a mental illness. It is
quite common for people in the general population to experience passing and infrequent
episodes of hallucination, and many people recover completely.
• Delusional disorder does not usually lead to severe impairment or change in personality,
but delusional concerns may gradually progress. Most patients can remain employed as
long as their work does not involve things related to their delusions.

8. T H A N K Y O U
David Rajasekaran Prasannakumar 1527