4. Risk of bias summary for trials in the included reviews.

Review	N trials	randomisation %			Sustained abstinence %	Biochemical validation %	Blinding %
		Low risk	Unclear risk	High risk			Low risk
NRT	147	25	72	3	70	86	33
Antidepressants	60	48	50	2	85	85	50
Nic recep partial ags	24	66	33	‐	75	84	58
Anxiolytics	7	‐	100	‐	29	29	0
Clonidine	6	‐	100	‐	0	67	0
Lobeline	0	No included studies
Mecamylamine	2	100	‐	‐	100	100	100
Nicobrevin	0	No included studies
Nicotine vaccines	4	25	75	‐	50	50	50
Opioid antagonists	4	50	50	‐	50	100	100
Rimonabant	3	‐	100	‐	100	100	0
Silver acetate	2	‐	100	‐	100	100	50

Numbers from columns 3 to 8 are percentages of the total number of trials for each review.