The much-publicized suicide last week of comedian-actor Robin Williams provided another tragic reminder that no amount of wealth or fame, no mental toughness or great physical gifts can keep the black dog at bay.
"One does not abandon, even briefly, one's bed of nails," the author William Styron, who battled severe depression, wrote in Darkness Visible. "It is attached wherever one goes."
Even when one steps onto the playing field.
Baseball historians estimate that as many as 85 major-leaguers - many in their prime, others recently retired - have committed suicide over the years. A few, like Moore, were given a formal diagnosis of clinical depression. Most, though surely enduring the disease's tortures, were not.
In sports such as football, hockey, and boxing, the growing concussion epidemic has exposed - and quite likely exacerbated - the instances of suicide and depression.
Andre Waters, Junior Seau, Wade Belak, Marc Potvin, and Alexis Arguello are just a few of the well-known victims of an infirmity that rarely gets discussed in sports.
No one knows how many athletes suffer from depression. But various studies suggest that it's a higher percentage than in the world at large, and that in 2014 there could be more than ever.
If you're looking for the blues in sports, you don't have to travel to St. Louis.
For a 2013 study, researchers at Georgetown University compared a large group of current college athletes in a variety of sports with a similarly sized sampling of former athletes. Depression, they discovered to their surprise, was twice as prevalent in the younger group.
"We expected to see a significant increase in depression once athletes graduated, but by comparison it appears the stress of intercollegiate athletics may be more significant than we and others anticipated," said Daniel Merenstein, a lead author of the study.
And those stresses may be even worse in professional sports.
Our pastimes are populated by those most vulnerable to the ravages of depression. Among those ages 25 to 34, the American Medical Association reports, suicide is the second most common cause of death.
While it's generally conceded that depression is a genetic disorder, there clearly are factors in big-time sports that may worsen the condition.
Tireless conditioning, rigorous travel, separation from families, the pressures of winning and sustaining a career, the withering glare of the spotlight - any or all of those things might push the susceptible past the breaking point.
It's not surprising that athlete suicides often occur in the years immediately after retirement.
Their self-worth, after all, is often linked closely to their sporting success. Many are able to sidestep the dark demons while performing. But when that outlet is no longer available, they are forced to face life without a familiar safety net.
It can be, for the severely depressed, a dangerous transition.
"When I went out on the court, I could shut everything out," said Bernard King, the NBA superstar who was abused as a youngster and turned to alcohol to ease the depression he believes it created. "That was a sense of escape."
When he had to miss a few seasons to rehab a severely injured knee, King no longer had that option, and the depression that ensued nearly overwhelmed him.
It's one of the great ironies of this 24-7 social media world that the more athletes are able to be seen, the less many of them want to be.
With virtually no place to hide, some, like King, retreat into seclusion where alcohol or drugs are their only companions, their only comfort.
"Being an athlete at the top of your game can be a lonely and dark place," British sports psychologist Michael Caulfield said. "It can be absolutely heartbreaking when something doesn't go your way - when your body lets you down, for example."
Our passion for sports blinds us to the vulnerabilities of its stars. We assume our heroes are all as strong inside as out. We like to glory in their ups while attributing their downs to some easily corrected shortcoming.
But sometimes it's more than a tweaked muscle that's bothering them. There are no MRIs that can detect depression.
Williams' death hit us so hard because it reminded us that harsh reality can intrude on the places we retreat to escape it - TV and the movies, the sports world.
In the Simon and Garfunkel song "Richard Cory," based on the Edward Arlington Robinson poem of the same name, the title character might easily have been a superstar athlete.
He had, after all, "everything a man could want: power, grace, and style."
And yet Richard Cory went home one night "and put a bullet through his head."
Maybe Williams' suicide will be the tipping point. Maybe professional athletes one day will be as ready and willing to treat a broken spirit as they are a broken bone.
And may the cheers they generate cheer their troubled souls.