COVID-19(26) Substance use(14) COVID-19 pandemic(13) Treatment(12) Result(11) reported(10) HIV(10) alcohol(9) disorder(8) Patient(7) public health(7) lockdown(7) change(7) Prevalence(7) participant(7) MOST(7) medication(6) Methadone(6) positive(6) social distancing(6) substance-related disorders(6) suggested(5) Opioid use disorder(5) effort(5) Effect(5) mental health(5) while(5) pandemic(5) Substance use disorder(5) female(5)