Troubled teens often come from homes where they are abuse or neglected. Kids who lack parental support, don't feel like they belong to the family and will tend to look for love somewhere else. Abused or neglected kids are often afraid to tell someone about their needs.
Time that is supposed to be spent in school trying to get an education is often wasted using up desk space, daydreaming, or skipping class because somebody neglected to take time to make sure basic skills were learned. Time that was supposed to be spent preparing for adulthood is lost because a mother or father neglected to spend time with their child, teaching them basic values and skills. Time that was supposed to be spent teaching children how to give and earn respect, lost because a father or mother decided to let the schools do it for them.