In this video Marc Whitehead, a Board Certified Disabilities Attorney, explains that most Long Term Disability Insurance policies have a Pre-Existing exclusion which can be used when a claimant has been disabled for less then a year, sometimes possibly two years.
The Insurance company will view your medical records of the year prior to the date of your disability, mostly to see what symptoms the claimant has complained of, what conditions you were diagnosed with and what medication you were taking.
If any of the symptoms from the year prior to your date of disability are able to be linked to your current disability. The insurance company is likely to deny your claim based on the Pre- Existing Condition Exclusion.