I was often bored in school, but because I was shy and a real teacher pleaser, I was also very well behaved. This was a big problem though, in that the boredom combined with the desire to please set me up for some serious perfectionism issues. Is your DS4 showing signs of perfectionism? If so, you might want to look at things from that angle. In general, I do believe that kids who are bored but don't act out often develop other unhealthy behaviors (like perfectionism), but I don't know any good articles.
