An irritated Joe Biden snapped at a reporter when pressed Wednesday on whether he had taken a cognitive test — defensively asking the interviewer if he was a junkie and tested for cocaine use.

The 77-year-old Democratic presidential nominee also confirmed he has never taken a cognitive test, countering remarks he made in June where he said he was “constantly tested” for mental decline.

The heated exchange happened during an interview with CBS correspondent Errol Barnett who asked Biden to clarify if he had taken a test to measure his mental acuity. Read more at NY Post