i am currently a few months in.. it is really hard.. but i keep getting told that it does help but it takes time.

3 girls from my group graduated yesterday after their yr in DBT and they were all saying they are doing a lot better now than they were before by far but there is still a long way to go in therapy before things are 'better'.

i'm not sure how helpful a 20 week one will be because from what i've been told it take about 4-6months before things 'click' and make sense and then you start understanding more and therefore it helping more..

good luck.