Syndrome old Technical Writers get, especially those in the Technical Writing too long. Symptoms include forgetfulness, confusing simple words like there and their (words that have been commonplace for their entire careers) and replacing pictures with 1,000 words each. Similar to Alzheimer's or Dementia in the average public.
The Tech Writer knew he had succumbed to documentia when he replaced a photograph of a beautiful sunset with a corresponding 1,000 word description.
To use an ability by instinct; to use innately an ability or reaction.
The bear instinctly used his hunting skills to catch the fish.