Neurofeedback effects on smoking behaviour. (A) Long-term effects on smoking behaviour. Smoking behaviour was assessed by the average number of cigarettes smoked per day from the last visit/telephone interview to the current one. Error bar (standard deviation, SD). (B) The correlation between the average deactivated neurofeedback performance and the number of cigarettes smoked per day at the 4-month follow-up. *P < 0.05; **P < 0.01; ***P < 0.005. NF = neurofeedback.