In all 620 hospital out-patients who screened positive for both tobacco and alcohol moderate risk in four hospitals were randomized into 2 control and 1 intervention condition using the hospital as a unit of randomization ( 2 intervention and 2 control hospitals ) to 405 patients in the two control groups ( tobacco only intervention , n = 199 , and alcohol only intervention , n = 206 ) and 215 in the intervention group .