Medical Definition
From the New England Journal of Medicine, added March 21st, 2010:

Lifesong Disorder

Mental and Physical Disorder affecting nearly 37% of the world's population, and growing rapidly. Still under investigation, it is difficult to pinpoint the exact causes and reasons for many patients' reactions to particular songs.

Physical Symptoms
- Chest Pain
- Dizziness
- Migraine
- Tingling of limbs
- Hyperventilation
- Drymouth
- Nausea
- Disorientation
- Fever
- Hypertension
- Chills
- Hives / Rash

Mental Symptoms
- Feelings of panic or fear
- A false assumption that the patient's life is tied to the song; feeling of helplessness or loss of control
- Egocentric ideals; the patient believes that they're somehow special
- Overwhelming sensitivity; one can be painfully blinded by light or even feel as though they can taste the smells on the air

For some people, the reactions to their 'song' is highly euphoric and peace-inducing. For others, it can be a painful and torturous experience. For those who wish to consider treatment, there are a small amount of options available.

Treatment Options
- Voluntary admittance to a psychiatric ward or asylum; this option has seemed to work quite well for numerous patients who have a hard time accepting their disorder.
- Isolation from music; this option proves successful in suppressing the panic attack-like symptoms that one's 'song' brings about.
- Inner Ear Surgery; only for those who suffer from severe reactions. Still under critical research, this procedure pinpoints the key tones and frequencies in one's 'song' and then alters the hearing of the patient so that the song will not affect them. Cons include a partial loss of hearing, and in rare cases, constant ringing in the ears.

Research is still being conducted in hopes of finding a medication that suppresses the symptoms while bypassing a cure. Much like the days when medications for the common cold were meant to soothe a sore throat or a stuffy nose, these would be meant to keep the heartrate steady and block physical reactions due to the part of the brain that reacts when that patient's particular song is heard. Very few advances have been made, but the work that has been done is largely significant.

Developing theories in the Lifesong community state that some experience similar symptoms in conjunction with what are typically considered ballads and various romantic songs. The key difference is mental -- the patient is convinced that the song governs how their romantic relationships are to be carried out, instead of feeling as though their lives in general are being controlled by the song. Medical research is still studying this particular branch of the disorder, but has yet to find substantial evidence of any such condition.