Ah, my first post...
On the topic of mental toughness and psychological intensification:
Being an avid sports fan, I find that "mental toughness" is a quality which is only measurable in truly adverse conditions. We speak of mental toughness and psychological intensification in instances where an athlete is at a significant disadvantage as compared either to his rivals or to his normal physiological state of being, instances such as sickness, fatigue, grief, mechanical failure, etc.
It is therefore difficult to come to any conclusion with regard to Armstrong's mental toughness because, both by his own design and by the great privilege of luck, he never faced adverse conditions. Of all the Grand Tours, he focused exclusively on Le Tour, thereby reducing to almost nil the possibility of being overly fatigued for Le Tour or coming into Le Tour with an injury.
During his 7 years with U. S. Postal/Discovery and subsequent return with Astana, he always rode with the best team in the peloton. He had the best domestiques, the best support staff and, beyond this competitive advantage, he had the best doctors and the best system of doping and masking. His doping also meant that he fatigued far less than other likely more talented cyclists.
In none of his 7 victories did he suffer any significant mechanical failure apart from a slight pedal malfunction for 1 mountain stage in 2003. His entourage of bodyguards and lawyers insulated him from the criticisms of doubters and probing journalists and ensured that all he had to focus on was his training and his doping strategy.
I cannot think of any great tragedy, such as a death in the family or some debilitating illness, that has ever befallen him during his period of dominance.
Armstrong was no doubt extremely competitive, but there's absolutely no evidence that he is truly mentally tough, because he's never had to rely on mental toughness to win anything. The circumstances for his victories were almost cruelly ideal to his advantage and to the disadvantage of his opponents.