Chapter 16
Other Psychiatric Syndromes
106
, Chapter 16: Other Psychiatric Syndromes
Important conditions
1. Psychotic conditions
A. Delusional misidentification syndrome.
i. Capgras syndrome (illusion of doubles).
ii. Fregoli syndrome.
iii. Intermetamorphosis.
iv. Syndrome of subjective doubles.
B. Lycanthropy.
C. Cotard’s syndrome.
D. Folie a deux (induced psychosis).
E. Ekbom’s syndrome (delusional parasitosis, delusion of infestation).
F. Erotomania (De Clerambault’s syndrome).
G. Morbid jealousy (Othello syndrome).
2. Non-psychotic conditions
A. Couvade syndrome.
B. Charles Bonnet syndrome.
C. Ganser’s syndrome (syndrome of approximate answers).
D. Diogenes syndrome (senile squalor syndrome).
E. Munchausen syndrome.
F. Munchausen syndrome by proxy.
1. Psychotic conditions
Management consists of treating the underlying disorder, e.g. treatment with an antipsychotic (e.g. olanzapine or
risperidone) or an antidepressant (e.g. SSRI).
A. Delusional misidentification syndrome
• An umbrella term for a group of delusional disorders that involve a belief that the identity of a person, object
or place has been altered.
• This syndrome is usually considered to include four main variants:
i. Capgras syndrome (illusion of doubles)
o Capgras syndrome scenario: a woman insists that her husband is not her real husband but
someone disguised as him.
o Features of the condition
✓ The most common type of delusional misidentification syndrome.
✓ Not an illusion but a delusional disorder in which the person believes that a close relative or a
spouse has been replaced by an exact double.
✓ Usually associated with affective disorders or schizophrenia, but can occur with organic
disorders.
✓ Females > males.
ii. Fregoli syndrome
o Fregoli syndrome scenario: a woman is convinced that her boyfriend often changes his
appearance to that of other people (“look-alikes”) in order to follow her.
o Features of the condition
✓ The delusional belief that one or more familiar persons, usually persecutors following the
patient, repeatedly change their appearance and are actually a single person in disguise.
✓ Usually associated with schizophrenia but can occur with affective or organic disorders.
iii. Intermetamorphosis
o Intermetamorphosis scenario: a woman is convinced that people swap identities with one another.
She denies that they change their physical appearance.
o Features of the condition
✓ The belief that people in the environment swap identities with each other while maintaining
the same appearance.
iv. Syndrome of subjective doubles
o Syndrome of subjective doubles scenario: a woman believes there is a double of herself who
undertakes actions specific to that person which do not mirror her own activities.
o Features of the condition
✓ A person believes there is a doppelganger or double of themself carrying out independent
actions.
107
Other Psychiatric Syndromes
106
, Chapter 16: Other Psychiatric Syndromes
Important conditions
1. Psychotic conditions
A. Delusional misidentification syndrome.
i. Capgras syndrome (illusion of doubles).
ii. Fregoli syndrome.
iii. Intermetamorphosis.
iv. Syndrome of subjective doubles.
B. Lycanthropy.
C. Cotard’s syndrome.
D. Folie a deux (induced psychosis).
E. Ekbom’s syndrome (delusional parasitosis, delusion of infestation).
F. Erotomania (De Clerambault’s syndrome).
G. Morbid jealousy (Othello syndrome).
2. Non-psychotic conditions
A. Couvade syndrome.
B. Charles Bonnet syndrome.
C. Ganser’s syndrome (syndrome of approximate answers).
D. Diogenes syndrome (senile squalor syndrome).
E. Munchausen syndrome.
F. Munchausen syndrome by proxy.
1. Psychotic conditions
Management consists of treating the underlying disorder, e.g. treatment with an antipsychotic (e.g. olanzapine or
risperidone) or an antidepressant (e.g. SSRI).
A. Delusional misidentification syndrome
• An umbrella term for a group of delusional disorders that involve a belief that the identity of a person, object
or place has been altered.
• This syndrome is usually considered to include four main variants:
i. Capgras syndrome (illusion of doubles)
o Capgras syndrome scenario: a woman insists that her husband is not her real husband but
someone disguised as him.
o Features of the condition
✓ The most common type of delusional misidentification syndrome.
✓ Not an illusion but a delusional disorder in which the person believes that a close relative or a
spouse has been replaced by an exact double.
✓ Usually associated with affective disorders or schizophrenia, but can occur with organic
disorders.
✓ Females > males.
ii. Fregoli syndrome
o Fregoli syndrome scenario: a woman is convinced that her boyfriend often changes his
appearance to that of other people (“look-alikes”) in order to follow her.
o Features of the condition
✓ The delusional belief that one or more familiar persons, usually persecutors following the
patient, repeatedly change their appearance and are actually a single person in disguise.
✓ Usually associated with schizophrenia but can occur with affective or organic disorders.
iii. Intermetamorphosis
o Intermetamorphosis scenario: a woman is convinced that people swap identities with one another.
She denies that they change their physical appearance.
o Features of the condition
✓ The belief that people in the environment swap identities with each other while maintaining
the same appearance.
iv. Syndrome of subjective doubles
o Syndrome of subjective doubles scenario: a woman believes there is a double of herself who
undertakes actions specific to that person which do not mirror her own activities.
o Features of the condition
✓ A person believes there is a doppelganger or double of themself carrying out independent
actions.
107
