ion Human (Bauer 1998) Transmission risk HIV No info OST ↓ Frequency of injection drug use Human (Kwiatkowski and Booth 2001) HIV cART OST • ↓ Frequency of heroin injection • ↑ On ARV Human (Pettes et al. 2010) Motor and visual function HIV No info OST • ↓ Digital Finger-Tapping test • ↓ Visual motor pu