It is important to understand what the laws consider a disability to be, especially if you intend on applying for disability benefits such as Social Security Disability or Supplemental Security Income.
Social Security Administration definition
The SSA defines disability to determine who qualifies for the benefit programs. It considers disability as any inability to engage in a substantial gainful activity due to a physical or mental impairment that a doctor can determine medically. This disability must last continuously, or be expected to last, for at least 12 months or result in death.
I have had some claimants fail to appeal a denial because they read the denial notice to require that their disability must last 12 months before they can be found disabled. Other claimants wait to apply until their disability has lasted twelve months. Don't make this mistake. If you expect your disability to last for at least 12 months, go ahead and file and if you are denied before you have been disabled for 12 months, go ahead and appeal.
For disability or impairment to be medically determinable, a doctor must be able to prove it using clinical and laboratory diagnostics. Although, a doctor's statement alone is not sufficient to prove disability to collect Social Security or SSI benefits, a statement from your treating doctor explaining how your medical impairment is disabling and explaining and referring to the tests that support the finding of that disabling impairment, can greatly assist you in proving that you are disabled.