Here is an AAMC piece about BS/MD programs. While these curricula do provide some benefits to students with an early interest in medicine, I am generally not a proponent of the BS/MD option, as it really precludes most participants’ ability to take full advantage of the college experience; the caveat may be 8-year programs (like Brown or Tufts) that don’t accelerate students, as much as give them early assurance of admission to medical school (assuming individuals maintain their grades). 

My bias is that taking more time – for example, a gap year – is a way to enjoy the school experience and approach medical training with maturity and career choice confidence.