Age, mean ± SD, years | 31.2 ± 10.9 |
Sex, male:female, n (%) | 7 (35):13 (65) |
Maximal axillary temperature, ℃ | |
Mean ± SD | 38.0 ± 0.4 |
Range | 37.5 – 39.0 |
Fever duration | |
Mode | 2 years |
Range | 2 months – 7 years |
Fever subtype, n | |
1) Usually a normal temperature, but suddenly develops a high fever of 38 °C or higher | 0 |
2) A low-grade fever in the 37 °C range persists for more than several weeks | 8 |
3) A low-grade fever in the 37 °C range intermittently | 4 |
4) A continuous low-grade fever in the 37 °C range and sometimes a high fever of 38 °C or higher | 8 |
Visited psychiatrists, n (%) | 13 (65%) |
Final diagnosis of comorbid psychiatric disorders (includes duplicate diagnoses), n | |
None except for functional hyperthermia | 4 |
Depressive disorders | 4 |
Adjustment disorders | 3 |
Anxiety disorders | 3 |
Somatic symptom and related disorders | 2 |
Neurodevelopmental disorders | 1 |
Post-traumatic stress disorder | 1 |
Presence of physical disease, n (%) | 8 (40%) |
Comorbid physical diseases (includes duplicate diagnoses), n | |
Premenstrual syndrome | 5 |
Irritable bowel syndrome | 3 |
Orthostatic dysregulation | 2 |
Tension-type headache | 2 |
Functional dyspepsia | 1 |
Sleep apnea syndrome | 1 |
Overactive bladder | 1 |
Hypertension | 1 |
Background factors, n | |
Stressful events within the past six months before the onset of symptoms | 18 |
Inflammatory events, such as viral infection, just before symptom onset | 8 |
Both stressful events and inflammatory events before the onset of symptoms | 7 |
Adverse childhood experiences | 5 |