Scott Higginbotham says James Slipper’s cagey persona meant he never knew the full extent of his troubles.

The Queensland and Wallabies veteran copped a two-month ban and $27,500 fine from Rugby Australia after it was revealed on Thursday he had twice tested positive to cocaine this year.

Reds captain Higginbotham, a good mate of Slipper’s, said he knew of the prop’s mental health struggles but didn’t have “any idea” about his drug habit.