Background: Efavirenz has been a mainstay of antiretroviral therapy (ART) for over 15 years in the US. Its association with neuropsychiatric side effects may influence clinical prescribing and management. Methods: We included HIV-infected adults enrolled in care at seven sites across the US, who initiated combination ART between 1999 and 2015. We examined the proportion initiating and continuing on efavirenz, overall and by mental health status. Log binomial and Cox models were used to estimate associations between mental health, clinical and sociodemographic characteristics and initiating or switching from efavirenz as first-line ART. Results: Of the 8,230 participants included, 3,710 (45%) initiated efavirenz. In multivariable analyses, prior mono- or dual-ART, ART initiation after 2006, being female, intravenous drug use, antidepressant prescription, previous mental health diagnosis and baseline CD4+ T-cell count >350 cells/mm3 were inversely associated with initiating efavirenz. Participants initiating efavirenz had a faster time to a regimen switch, compared with those initiating an efavirenz-free regimen (P-value <0.01). Among efavirenz initiators, starting efavirenz in more recent time periods and a previous mental health diagnosis were associated with faster time to switching from efavirenz. Despite this, 40-50% of participants with a previous mental health diagnosis initiated and continued on efavirenz for much of the follow-up period. Conclusions: Multiple clinical factors, including mental health diagnoses, appeared to influence efavirenz use. While mental health diagnosis status and more recent treatment starts were associated with shorter duration of efavirenz therapy, a previous mental health diagnosis did not preclude efavirenz initiation or continuation in many participants.