While many aspects of LGBT health disparities are heretofore uninvestigated, at this stage, it is known that one of the main forms of healthcare discrimination  LGBT individuals face is discrimination from healthcare workers or institutions themselves. A systematic literature review of publications in English and Portuguese from 2004–2014 demonstrate significant difficulties in accessing care secondary to discrimination and homophobia from healthcare professionals. This discrimination can take the form of verbal abuse, disrespectful conduct, refusal of care, the withholding of health information,  inadequate treatment, and outright violence. In a study analyzing the quality of healthcare for South African men who have sex with men (MSM), researchers interviewed a cohort of individuals about their health experiences, finding that MSM who identified as homosexual felt their access to healthcare was limited due to an inability to find clinics employing healthcare workers who did not discriminate against their sexuality. They also reportedly faced "homophobic verbal harassment from healthcare workers when presenting for STI treatment". Further, MSM who did not feel comfortable disclosing their sexual activity to healthcare workers failed to identify as homosexuals, which limited the quality of the treatment they received.