“…These included two studies examining use of illicit drugs ( Barratt et al, 2015 , Bauermeister et al, 2012 ), six studies that recruited men who have sex with men, and one study that recruited women who have sex with women. Other studies recruited participants with rare diseases such as myasthenia gravis (an auto-immune disease: Richards et al, 2014 ), Klinefelter syndrome ( Close et al, 2013 ), Haemophilia ( DiBenedetti et al, 2014 ) and neurofibromatosis ( Johnson et al, 2014 ). Other populations targeted included people living with HIV ( Yuan et al, 2014 ), ethnic minorities ( Carlini et al, 2014 ), parents of adolescents ( Gilligan et al, 2014 ), low-income earners ( Lohse, 2013 ), people with mental disorders ( King et al, 2014 , Morgan et al, 2010 ) and health professionals ( Child et al, 2014 , Mannix et al, 2014 ).…”