Except for the three-plus months following my quadruple bypass in 2007, I've never suffered from writer's block, and that wasn't writer's block as it's most commonly defined. Instead, it was a drug-induced block that disappeared as soon as I made my cardiologist aware of the problem and he modified my drug regimen.
I do, however, sometimes suffer from writer's constipation. The stories are still in my head and the words still want to come out, but they don't come easily. Instead of them flowing out in paragraphs and pages, I must squeeze them out one word or one sentence at a time.
There's no perceptible difference in quality between the work I squeeze out and the work that flows out. There is, however, a difference in how I feel during the creative process. I feel frustrated. What I've not determined is if writer's constipation causes my frustration or if something else causes the frustration and writer's constipation is the result.