I think it would be useful to discuss the following ideas with your doctors.

Keep a diary of the symptoms and relate that to the peaks and troughs of the daily drug regimen. For instance, is the psychosis absent before the first dose of the day, but present a hour after the dose?

A paper by Latoo et al. gives some pointers of how to continue [1]:

"The main extrinsic cause of Parkinson’s disease psychosis is thought to be the medication used to treat the condition ... , although levodopa and catechol-O-methyl transferase (COMT) inhibitors are implicated to a lesser extent than other drugs."

I take this to mean that one should withdraw first agonists, possibly replacing them with levodopa to make up for any motor deficiencies (see posts on levodopa equivalent dose for conversion factors). It may be possible to get some extra benefit from using a COMT inhibitor such as entacapone (Stalevo = levodopa/carbidopa/entacapone). A further benefit may come from smoothing out levodopa plasma levels by taking into account the pharmacokinetic properties of levodopa. Possibly, by reducing the dose, while increasing its frequency.

Reference:

[1] "Diagnosis and management of psychosis in Parkinson’s disease"
Javed Latoo MBBS, DPM, MRCPsych, Minal Mistry BM, BSc, MRCPsych, MSc, PGDipEd, Francis J Dunne MRCPsych, FRCPsych
Progress in Neurology and Psychiatry
Volume 16, Issue 5, Version of Record online: 12 OCT 2012
Diagnosis and management of psychosis in Parkinson's disease - Latoo - 212 - Progress in Neurology and Psychiatry - Wiley Online Library

John