Heroes are often defined and made what they are by two things: the villains they face and the burdens they carry. Superman carries the burden of fear and anxiety, living a life afraid of breaking something, of killing someone should be be careless with his power. In some ways, Spider-man fought off depression after the death of his Uncle Ben by turning to crime-fighting. Batman turned his fear and anxiety into a weapon in his personal war, fueling his lone crusade against crime. However, in very few heroes is the relationship between burden and heroism as blatant and as prominent as in Tony Stark, the Iron Man.
The armor worn by the Iron Man, unlike the costumes of so many other heroes, is more than a mere tool for fighting crime. The armor also bears several components designed to help him cope with his physical ailments. Tony Stark's heart was compromised in Vietnam, such that the armor's primary purpose was to sustain him – keep him alive and moving – long enough to get proper medical care. In many ways, the early years of his career was marked with mild hints of depression. The armor was less of a tool in his eyes, and more a reminder of the frailty of his condition. The fact that the chronic pain he felt was alleviated better by the armor than by medication only added to his problems.
Still, despite the frailties, the Iron Man continued to do what he felt needed to be done. More so than any other hero, he risks his life whenever he engages his enemies in battle. The slightest malfunction or damage to his armor could prove fatal for him. The slightest disruption in the systems could cause the systems to go berserk and take many innocent civilians along with him. The burden has, at certain times, been too great for the character to bear. In a contrast to many other superheroes around him, Tony Stark tried to fight his depression and the pressures of his life in a very human way: alcohol.
Of course the decision to make him an alcoholic was controversial, but then, Marvel Comics has always pushed the line that way. Harry Osborne had been a drug user in an even more sensational storyline from the Spider-man comics. However, the difference here was that, unlike Osborne, Stark was a hero. As a hero, he was supposed to be above the petty squabbles and flaws of ordinary human beings. He eventually recovered, but not before his alcoholism caused great turmoil among his teammates and pushed his already strained relationships to near-breaking point.
The Iron Man character is often overlooked in the long list of superheroes that have become more human over the years. This is probably due to the fact that Tony Stark isn't quite as fitting into the comic book niche-worlds that others seem designed for. Spider-man is the everyman of the superhero world, designed so that anyone who reads his comic can find something about him that they can relate to. Superman is the vision of an ideal, a dream given form and power. The Batman represents the darkness in everyone, honed and shaped into an overwhelming power. It is arguable, but there are some that would say Tony Stark is more human than any of the above. The armor may make him seem invincible, but like a turtle, underneath the shell is something soft and vulnerable.