Are adult add and adhd tests requested by a psychatrist expensive or no ?

It depends. : Testing may be 100% covered by insurance or may be something you need to pay for. Some basic pen-and-paper tests can be done by a non-specialist like a pediatrician, and typically have very accurate valid results. Ask your doctor before taking any tests if you are worried about the cost involved. They can give you a list that you can discuss with your insurance company to verify that they'll pay.

Ask!: Ask the psychiatrist how much therapy, testing, and other interventions will cost. It may be less expensive than the consequences of living with untreated adhd.