I just increased my clozapine from 225mg to 250mg 3 days ago.
And now since yesterday I’m not able to speak properly, i stop in middle of the sentence, i mumble, i forget the words i wanna say. I simply go confused about what i wanna say and words come out incorrect.
I have been taking clozapine since 5 years and never had this problem.
Pdoc said to please go back to the previous prescription when I was doing well. I said ok, i will go back to 225mg.
I am on 500mg a day of Clozapine and have not experienced the that. 
I have been to as high as 350mg before and never had this problem but i dont how i got this speech problem now.
Never heard of that side effect, but if your pdoc says go back you should go back.
No more speech problems now after reducing clozapine to 225mg.
I have stuttering. I take 800mg of Clozaril a day and was also on 30mg of Prolixon a day. I thought my stuttering was due to the Prolixon so went off it. My stuttering has somewhat stopped but not completely.
I had this side effect when I went up in dosage too quickly…for example, when I first started clozapine I went from 50mg-300 in a couple of days…like you I couldn’t communicate properly…I had in my mind what I wanted to say but it came out different.
We started from scratch after that…going from 12.5 for a week to 25mg for a week, going up by 50mg every week or so until I got to 300mg…and since have not had any issue…
I have great empathy for you as I know how horrible and scary that is…
i had something like that happen to me once. Was on either quintapine or invega i believe
I would like to update that my speech problems on clozapine was because of myoclonic jerks(type of seizures), when i increased my anticonvulsant drug dose, the speech problems went away