That BPD, similarly C-PTSD, results in fairly inflexible behavioural patterns that will be the more difficult to change the older one gets. And the older one gets, the bigger the damage that cannot be undone, and the shorter the time to benefit from any improvement.

And every behaviour related setback only solidifies my tendency to isolate, thus reinforcing negative beliefs and self-defeating behaviour. I haven't yet found a remedy, nor have I heard of DBT in my area.