Claim, maybe, true, no.
JFK was on drugs, but not recreational. The most reliable information I have found shows that both Jackie and John were kept 'high' on methamphetamines by the White House Physician. This was in an effort to allow them to handle the demands of being President. At the time, amphetamines and their derivatives had not the negative connotation they do today. The President being kept "UP" by meth injections was likely considered no worse than mouthfuls of 'bennies' and black beauties the truck drivers were taking.
Jackie had to be hospitalized several times due to 'overexhaustion'( Known today as tweaking too long, and crashing.)