IN my experience IOP and PHP both focused on mental health. I don't have a substance issue. I think substance abouve has its own IOPs and pops away from mental health groups. have there own IOP/PHP for those issues. IOP is just a less intense usually a step down from a PHP program. In my experience PHP pick you up drive you to the program and you are there all day and get served lunch. They are like hospital but you sleep at home. IOPs are a further step down and you have to get yourself to the program and its only a couple hours of mainly group talk. It can be mornings or afternoon s so there's an option to work. Phps have more information groups and coping skill groups along with the talk therapy.