“…Depression and depressive symptoms are consistently observed in smoking adolescents compared to their non-smoking peers (Wu and Anthony, 1999 ; Goodman and Capitman, 2000 ; Albers and Biener, 2002 ; Jacobsen et al, 2007c ; Needham, 2007 ; Ilomäki et al, 2008 ; Audrain-Mcgovern et al, 2009 ; Morrell et al, 2010 ; Slomp et al, 2019 ). Most studies of this age group found smoking positively predicted the development of depression and depressive symptoms (Brown et al, 1996 ; Stein et al, 1996 ; Choi et al, 1997 ; Goodman and Capitman, 2000 ; Windle and Windle, 2001 ; Albers and Biener, 2002 ; Brook et al, 2002 , 2004 ; Galambos et al, 2004 ; Duncan and Rees, 2005 ; Rodriguez et al, 2005 ; Boden et al, 2010 ; Moon et al, 2010 ; Jamal et al, 2011 ; Beal et al, 2014 ; Gage et al, 2015 ), but not all findings have supported this association (Wang et al, 1996 ; Repetto et al, 2005 ; Clark et al, 2007 ; Munafò et al, 2008 ; Hu et al, 2011 ; Strong et al, 2014 ). Importantly, the relationship between smoking and depression in adolescence has been suggested to be bidirectional, such that baseline depression contributes to the risk for future smoking habits just as baseline smoking predicts depression (Brown et al, 1996 ; Windle and Windle, 2001 ; Galambos et al, 2004 ; Needham, 2007 ; Audrain-Mcgovern et al, 2009 ; Moon et al, 2010 ).…”