According to a 47-page secret American Military Intelligence dossier and the medical diaries and journals of his personal physician Dr Theodor Morell, Hitler was a nervous hypochondriac with an extreme drug habit.
The Fuhrer is said to have been hooked on a cocktail of over 74 different types of medications including crystal meth.
The drug can give an intense and prolonged high but a severe comedown, where feelings of hopelessness and despair are common, the NHS writes.
The revelations are part of an upcoming Channel 4 documentary entitled Hitler’s Hidden Drug Habit.
The Nazi leader is said to have taken crystal meth before his final meeting with Italian fascist leader Benito Mussolini in July 1943, during which he reportedly ranted solidly for two hours.
Dr Morell’s diaries, which have been locked away since 1945, also suggest Hitler was treated with Mutaflor for stomach cramps, barbiturate Brom-Nervacit, the morphine-based sedative Eukodal, bulls’ semen for testosterone boosts and Pervitin, a pill containing crystal meth.
The programme contains footage the German censors tried to repress and which appears to suggest that by 1945 Hitler was in an advanced stage of a serious degenerative disease, believed to be Parkinson's.
Dr Morell’s journal also appears to dismiss popular rumours Hitler had only one testicle or was a homosexual, noting in November 1945: “He was neither a pervert nor a homosexual. His sex organs showed no indication of abnormality.”
Bill Panagopoulos, an American collector who discovered the dossier said: “Morell was a quack and a fraud and a snake oil salesman.
“He should not have been practising medicine anywhere outside a veterinary clinic.”
Last year one of Germany’s leading post-war writers claimed Nazi troops used crystal meth in order to stay awake during marches.
Called an “alertness aid” and packaged as Pervitin, widespread use of the drug was confirmed in letters home penned by Nobel prize winner Heinrich Böll, as published by Der Spiegel.
In November 9 1939, whilst Böll was in Poland, he wrote to his parents: "It's tough out here, and I hope you'll understand if I'm only able to write to you once every two to four days soon. Today I'm writing you mainly to ask for some Pervitin... Love, Hein."
As he became, by his own admission, "cold and apathetic, completely without interests," he asks for more and more of the drug.
Aside from handing out Pervitin, Military doctors dosed chocolate with methamphetamine too, giving Fliegerschokolade or "flyer's chocolate" to pilots. The speed sweet was given to tank crews too, and dubbed Panzerschokolade or "tanker's chocolate."
But the drugs came with horrendous side effects. Aside from dizziness, depression, sweating and hallucination, some soldiers died of heart failure while others who shot themselves in a psychotic haze
The drastic physical effects of methamphetamines, taken in much larger quantities by addicts today, are laid bare in the below gallery of users.
The images feature on Rehabs.com, an American website which gives information on the treatment of various addictions, lists of clinics and general advice.
It also provides an account of the rehabilitation process and recommendations for relapse prevention.
Free, confidential information and advice is available by calling the Release Drugs Helpline on 0845 45 00 215.
Hitler’s Hidden Drug Habit will air on Channel Four on 19 October 2014.