@ DarkWalker, I guess the problem is when your writer is the legacy founder and/or the only sim in your house. Then it becomes really hard to actually get writers block. I tried dazed by drinking 2+ coffee which also produces dazed but that didn't help. Did you look at coding to understand how writers block works like a need? That would make sense because at level 7 it took hours and hours of writing before my sim got writers block.
Tunings, actually, but yeah, that was from looking at the game files. The hidden need is commodity_Buff_Object_Writing-WritersBlock , which "decays" (i.e., removes the writers block) at 0.41667/minute. The sim needs to get 200 points of that writers block hidden need go be struck with the Writers Block moodlet.
I'm not completely sure how fast the sims accrue writers block points, though. They seem to gain those points at 0.81/minute while writing, though I suspect the decay is still in effect, for a net gain of 0.39333/minute at skill 1. Those points also appear to be reduced by the effective level of the Writing skill, up to a 60% reduction at level 10. Being inspired further reduces how fast sims get Writers Block (and, in fact, might, for practical purposes, make it impossible to get even at low levels).
If it works like I suspect, it means that sims with writing skill 8 or above are for practical purposes immune to getting Writers Block unless something is artificially reducing their effective skill levels, and sims with a effective skill level of 7 (such as a sim with Writing 10 kept dazed or enraged during the whole process) need two days writing nonstop to get it. And I do mean non-stop, every minute not writing requires about 6 minutes to make up for the lost time.