Yes, MassHealth is secondary, while you are on your parents' insurance. But, once you are off your parents' insurance, it becomes primary.

Medicaid (MassHealth) is always the insurance "of last resort." However, once it kicks in, it is about as comprehensive as a health insurance policy can get. It covers everything. So you have nothing, really, to worry about. Plus, Massachusetts tends to fund its Medicaid program more generously than any other state. So what meds and providers it allows you to access should be reasonably close to what you get through your parents' policy. Plus, Massachusetts has one of the best healthcare infrastructures of any state. You've got some of the best hospitals and physicians in the world in your state, so healthcare standards there are high. You can really relax.

Since you've been too old for CHIPS for a few years, I would presume your parents already got you transferred over to adult Medicaid, if that didn't happen automatically, which may have been the case. Ask them to show you your Medicaid and MassHealth cards. If they prefer to hold on to them for you, get copies made. Then carry the copies in your wallet.

I would be surprised, if you have any co-pays at all, once MassHealth becomes your primary. As in other states, MassHealth probably operates through private healthcare networks with which it has contracts. Typically, you would choose from amongst those networks. (Blue Cross and OptumRx may have those contracts. I think OptumRx would be for prescriptions only.) They might differ slightly from each other in which doctors and which meds they steer you towards. As a MassHealth subscriber, you won't be able to get any other insurance (besides your parents'.) And you wouldn't want to.

It sounds like your parents are a bit confused, themselves, or they would have told you that you have nothing to worry about. So do ask your dds worker to help you understand. Your dds worker may not be expert and may have to refer you to a dds supervisor. Or go to Income Support and ask to speak to a supervisor there. Ideally, have your parents sit in on the explanation.