Tell them everything. You may or may not be aware of the full spectrum of disqualifying conditions. Just because you think something is trivial doesn't mean the military agrees.
If you develop a disqualifying condition mid-HPSP and inform the program, you may be dropped but the military is not going to demand to be refunded monies already paid on your behalf. The exception might be if you acquired that condition while committing some crime; eg, you snap your spine while DUI'ing your car through a kindergarten.
Another bad way to go would be to conceal some condition, finish up the scholarship living high on the HPSP hog, then tell them you developed disqualifying condition XYZ three years ago. Then, the military will likely tell you to take a hike and, oh by the way, here's a bill + interest for everything the military paid for you or to you. Due in 120 convenient equal non-dischargable-in-bankruptcy installments.