“…Thus, one of the outstanding explanatory variables, because of its influence on drug consumption in adolescence, is the use of drugs by the peer group (Ciairano, Bosma, Miceli and Settani, 2008;Dick et al, 2007). In other words, friends' smoking behaviour (particularly the best friend) is one of the most influential factors in nicotine consumption behaviour of a teenager (De Leeuw, Engels, Vermulst and Scholte, 2009;De Vries, Engels, Kremers, Wet-zels and Mudde, 2003;Fisher, Winickoff, Camargo, Colditz and Frazier, 2007;Hall & Valente, 2007;Hoffman, Monge, Chou and Valente, 2007;Molyneux et al, 2004;Okoli, Richardson and Johnson, 2008;Otten, Engels and Prinstein, 2009;Piko, 2006). Nevertheless, the results of Szabo, White and Hayman (2006) suggest that prohibitions in the home in relation to tobacco reduce the likelihood of a teenager trying nicotine despite their friends' consumption behaviour.…”