常習
Common
Noun
Irregular
Transitive
Noun
1
noun (common) (futsuumeishi)noun or participle which takes the aux. verb surutransitive verbnouns which may take the genitive case particle 'no'
custom;common practice;habit
シンナーなどの常習性のある物をしてると言う事は、更正する可能性が低いと思います。
I think that, as he's using addictive substances like thinner, the chance of rehabilitation is low.