Classification of musical hallucinations and the characters along with neural-molecular mechanisms of musical hallucinations associated with psychiatric disorders

Table 1 Demographic and clinical data of musical hallucinations subjects

Group number	Etiology1	Case number2	Gender	Age in years, mean ± SD (range)3	Nationalities of the cases	Comorbidities
1	Hearing impairment	54 (77)	Male = 19, female = 35	69.0 ± 12.5 (27-89)	Australia, Belgium, Brazil, Espinal, Germany, India, Israel, Japan, Omaha, Romania, Netherlands, The United Kingdom, Türkiye, United States	Tinnitus, hearing loss, presbycusis, pre-lingual deafness, cochlear implants, pontine lacunar lesions, otosclerosis
2	Psychiatric disorder	64 (85)	Male = 20, female = 44	65.2 ± 16.4 (20-89)	Finland, Greece, Israel, Italy, Japan, Netherlands, Portugal, The Netherlands, The United Kingdom, United States	OCD, schizophrenia, Alzheimer, anxiety, ADHD, MDD, dementia, personality disorder
3	Brain lesion	16 (22)	Male = 5, female = 11	69.1 ± 12.2 (38-80)	Japan, Poland, United States	Stroke, traumatic brain injury, whiplash injury, left temporal lobectomy, brainstem lesion
4	Neuropathological syndromes	12 (14)	Male = 2, female = 10	77.1 ± 15.9 (45-101)	Germany, Japan, Spain, United States	Epilepsy, Parkinson disease, neurodegenerative disorder, Lewy body disorders, Charles Bonnet Syndrome etc.
5	Substance intoxication	18 (20)	Male = 8, female = 10	59.7 ± 19.3 (23-91)	Japan, United Kingdom, United States	Mirtazapine, tricyclic, ketamine, pentoxifylline, dipyridamole, quetiapine, triazolam, oxycodone, Transient amantadine
6	Unknown etiology	42 (53)	Male = 12, female = 30	72.9 ± 13.2 (29-88)	France, or Italy, United States	No comorbidities
7	Surgery	8 (9)	Male = 1, female = 7	61.3 ± 20.5 (27-79)	Brazil, Canada, United States	Childbirth in a female patient on hemodialysis
8	Infection/immune disorder	12 (14)	Male = 8, female = 4	65.3 ± 15.6 (27-82)	Canada, United States	Listeria rhombencephalitis, anti-IgLON5 disease, listeria rhombencephalitis
Total cases		226 (294)	Male = 75, female = 151	67.9 ± 16.2 (20-101)

¹The etiology groups of the subjects who were experiencing musical hallucinations. Two hundred and night four cases from the data pool can be classified into 8 groups according to their associated etiologies.

²Case number indicated the musical hallucination (MH) subjects’ numbers whose genders and ages were reported, the numbers inside parentheses summarized the total numbers of subjects whose genders were known and unknown.

³This column demonstrated MH subjects’ means, age, the SD, as well as the distribution of the age ranges (inside bracket).

OCD: Obsessive-compulsive disorder; ADHD: Attention deficit hyperactivity disorder; MDD: Major depressive disorder.

Table 2 Demographic characters of the subjects with musical hallucination associated psychiatric disorders

Psychiatric diagnosis1	Case number2	Sex	Age in years, mean ± SD3 (range)
Psychosis NOS/schizophrenia	40	Male = 6, female = 18, unknown = 16	71.7 ± 19.7 (20-89)
MDD	26	Male = 8, female = 17, unknown = 1	66.9 ± 11.5 (35-88)
Dementia	10	Male = 2, female = 8, unknown = 0	57.2 ± 18.7 (24-82)
ADHD	2	Male = 2, female = 0, unknown = 0	23, 40
Anxiety	2	Male = 0, female = 2, unknown = 0	78, 85
OCD	2	Male = 0, female = 1, unknown = 1	75
Adjustment disorder	1	Male = 0, female = 1, unknown = 0	57
Bipolar	1	Male = 0, female = 1, unknown = 0	66
Borderline personality	1	Male = 1; female = 0, unknown = 0	Unknown
Total number	85	Male = 19, female = 48, unknown = 18	67.1 ± 16.5 (20-89)

¹The different psychiatric diagnoses associated with musical hallucination (MH), totally 85 subjects from our sample pool can be classified into 9 subgroups according to their psychiatric diagnosis [attention deficit hyperactivity disorder, adjustment disorder, anxiety, bipolar, borderline personality disorder, obsessive-compulsive disorder dementia, major depressive disorder (MDD), psychosis NOS/schizophrenia].

²The MH subject numbers who are experiencing mental illness. For the groups of MDD, dementia and psychosis NOS/schizophrenia, multiple cases were reported.

³The ages, the means, the SD and the distribution of the age ranges (inside bracket) of the MH subjects with associated psychiatric disorders.

OCD: Obsessive-compulsive disorder; ADHD: Attention deficit hyperactivity disorder; MDD: Major depressive disorder.