If i have a teenage boy with new onset psychoses, do i want to get an mri with or without contrast?

With contrast: I would suggest getting the MRI with contrast as part of your initial evaluation. Most pediatric neurologists will want this study prior to a referral.

An MRI: with contrast will provide the most information. However, depending on the level of suspicion your doctor has for various diagnostic possibilities, a non contrast MRI might be sufficient. You should discuss the pros and cons of contrast relative to your son's particular clinical picture with your doctor.