- sarcoma
- schizophrenia
- seasonal affective disorder
- self injurious behavior
- senile dementia
- sepsis
- severe aortic stenosis
- severe depression
- severe obstructive sleep apnea
- sexual functioning
- sexually transmitted diseases
- sexually transmitted infections
- sezary syndrome
- sickle cell anemia
- sickle cell disease
- sinus infections
- sjogren's syndrome
- skeletal dysplasias
- skin cancer
- skin infection
- sleep apnea
- sleep deprivation
- sleep disordered breathing
- sleep disorders
- sleep disturbances
- sleep paralysis
- sleeping sickness
- smoking cessation
- social phobia
- spina bifida
- spinal cord injury
- spinal muscular atrophy
- sports injuries
- squamous cell carcinoma
- staph infections
- stigma
- stomach cancer
- stomach ulcers
- stress
- stroke
- subarachnoid hemorrhage
- subdural hematoma
- suboptimal response
- sudden cardiac arrest
- sudden cardiac death
- sudden death syndrome
- sudden infant death syndrome
- sudden sensorineural hearing loss
- systemic inflammatory response syndrome
- systemic lupus erythematosus
- systemic scleroderma
- systemic sclerosis