He became trapped in that space between words and could only stand and watch [...] the thoughtless boyish part of him crashing on out of sight blindly [...] while he, trapped, the grownup Al, watched in oddly impersonal suspense. (1.32)
Alfred's mental state is compared to that of a young boy throughout the novel, which serves to both illustrate his helplessness and show just how far he's deteriorated.
"That's what Gary and Caroline say too [...] They say he was a workaholic and that work was a drug which when he couldn't have it anymore he got depressed." (2.435)
While there's truth to this, Alfred's problems run way deeper than just unemployment. Gary has incentive to downplay his dad's problems—after all, if it happened to Alfred, then why couldn't it happen to him?
That his impulse, instead, was to jump to his feet and answer the phone [...] cast doubt on the authenticity of his suffering. He felt as if he lacked the ability to lose all volition and connection with reality the way depressed people did in books and movies. (2.530)
And now, a brief commercial interruption from Chip "I Wish I Were More Interesting" Lambert. To our surprise, Chip turns out to be the sane one in the family. Here's our advice for you, little buddy: Be careful what you wish for.
"The idea," Doug said, "is your basic gut cerebral rehab. Leave the shell and roof, replace the walls and plumbing. Design away that useless dining nook. Put a modern circuit breaker in." (2.680)
This is a distinctly modern idea about the mind. The brain—like any piece of property—needs renovation, upkeep, and modern amenities. We'll see the implications of this later.
From certain pop-psychology books on Caroline's nightstand, however, he'd learned to recognize the Warning Sign of clinical depression, and one of those Warning Signs, all authorities agreed, was a proclivity to inappropriate weeping. (3.18)
Trust us: Well people don't spend this much time trying to prove how healthy they are.
He'd had the sense, moments earlier, that Caroline was on the verge of accusing him of being "depressed," and he was afraid that if the idea that he was depressed gained currency he would forfeit his right to his opinions. (3.298)
Gary believes that he'll lose his standing in the family if he admits to having a mental illness. Whether or not he's right is beside the point—Gary is afraid of becoming Alfred.
Depressed? He was not depressed. Vital signs of the rambunctious American economy streamed numerically across his many-windowed television. (3.968)
Ah yes, there's nothing like a hot cup of denial to wake you up in the morning. Gary hides his fears in the financial world, but if there's something we've learned, it's that the market always corrects itself.
She reached behind her for the water glass from the sink. She filled it and refilled it at the bathtub's tap, pouring the hot water over her husband's head. With his eye's squeezed shut he could have been a child. (6.165)
It's hard to believe that this is the same man who terrorized his family for so many years. Although it makes us sympathetic toward Alfred's struggle, we find ourselves admiring Enid's dedication even more.
With the lifting of his "depression," he'd developed a new interest, hobbylike in its intensity, in frameable and collective railroad memorabilia, and he could happily have spent the whole day—the whole week!—pursuing it… (6.333)
It's worth noting that Gary "beats" depression by playing with model railroads—an activity Alfred detests for its phoniness. We'll let you connect the dots...
"My head doesn't seem to work right."
"I know. I know."
But Gary himself was infected, there in the middle of the night, by his father's disease [...] Gary, too, had the sensation of things dissolving around him (6.420-422)
There's no way that Gary can deny his mental health problems after his second psychotic episode in a year. That being said—never say never.