It's pretty well documented that the German army made use of meth and other stimulants to keep its troops going for days at a time, which played a part in the extremely rapid advancement of the early war. But I recently read that while this helped them in the short run, later in the war the German military machine was hampered by, well, systemic drug addiction.

Is this accurate? Do contemporary records or later accounts show that the military was actually significantly negatively affected by its drug use?