Two or three questions in various categories should be enough. Also, there are a number of excellent forms you can try. The American Medical Association also has history forms to assist with providing adolescent preventive services. Personally, I believe health history forms that kids can fill out on their own work well. Kids are used to forms, and there's a degree of anonymity with this type of information gathering.
Healthcare providers can then scan the form for issues that warrant further discussion.
Involve the parents As healthcare providers, we are in a unique position to work with parents. We know many parents get into trouble setting boundaries for their adolescent children because they can't decide where the boundaries should be. They are unclear themselves and transmit that ambiguity to their kids. Typically, parents suddenly feel they must become authoritarian, and kids, of course, balk. We tend to spend a lot of time providing anticipatory guidance to parents of young children.