Twelve studies met the inclusion criteria: 8 nicotine gum studies (n=616), 3 inhaler studies (n=138) and one microtab study (n=20). No published studies of lozenges were found.
P-values were reported for the studies reporting the outcomes of irritability, depression, anxiety, poor concentration, restlessness, sleep disturbance, hunger, craving and total withdrawal.
Irritability: the p-value was statistically significant in all 9 of the studies (6 gum, 2 inhaler, and 1 microtab).
Depression: the p-value was statistically significant in the one study (1 gum, 0 inhaler, and 0 microtab).
Anxiety: the p-value was statistically significant in 3 of the 4 studies (3 gum, 0 inhaler, and 0 microtab).
Poor concentration: the p-value was statistically significant in 5 of the 9 studies (3 gum, 1 inhaler, and 1 microtab).
Restlessness: the p-value was statistically significant in 2 of the 5 studies (2 gum, 0 inhaler, and 0 microtab).
Sleep disturbance: the p-value was statistically significant in one of the 2 studies (1 gum, 0 inhaler, and 0 microtab).
Hunger: the p-value was statistically significant in 2 of the 5 studies (2 gum, 0 inhaler, and 0 microtab).
Craving: the p-value was statistically significant in 7 of the 11 studies (3 gum, 3 inhaler, and 1 microtab).
Total withdrawal: the p-value was statistically significant in 6 of the 7 studies (5 gum, 0 inhaler, and 1 microtab).