No ... i am afraid but answer is i would not recommend this combination..
my reasons are below..
1) you are already on an anti psychotic in the form of zyprexa , so adding one more anti pscyhotic would open the shore for distressing side effects such as extrpyramidal side effects , weight gain , seizures , increased blood pressure and sugar levels.. increase cholestrol ,etc ..
2) you are already on 1 psychostimulant drug which works to improve concentration and attention in the form of provigil , which still i think you can tolerate , because of its different mechanism of action as compared to ritalin or adderall , but ritalin / adderall ,id at all used then even a minor dose would react with anti psychotic drugs that you are on making the drug efefcts ineffective and thereby leading to worsening of the clinical picture ..so i am sorry but i cannot suggest you something which is going to bring adverse effects to you ..
3) While i am open to the idea of you being add , but i strongly feel that the difficulty in concentration that you suffer from could very well be from unattended unaware depressive phase that you could be in which you might have not been noticed it and which can simulate symptoms of add..
4) My remedy for you would be to ask your doctor to raise the dose of lithium to 900 mg/ day , to be taken as 300 mg does , three times a day , morning , afternoon and evening , roughly in a gap of 6-8 hrs ..
5) another change that i will recommend is to raise the dose of provigil by 25 mg, that is by taking a separate dose of 25 mg in the afternoon other than the morning 100 mg dose , this will help with your cognition and concentration .
6) Add lexapro in the morning at dose range of 5-10 mg in the morning ...this is an anti depressant which will help you with your depressive cognition and also in improving your concentration an clear thinking ...
So, discuss these changes with your doctor and start on them and observe the symptoms for atleast 3-4 weeks , i am sure that you will no longer have complaints with your concentration and feel better ..
I hope this helps..
Wish you all the best..