 The assumptions used to estimate the recruitment period needed to reach that sample size are as follows: Using a conservative estimate of number of visits per day from those 18 years old and over 30 visits for each public clinic and 55 visits for private clinic, with 10 a prevalence of moderately risky levels of alcohol use, based on a study conducted in similar PHC centres in Kenya using the ASSIST; subtracting returning patients an average of 30. An enrollment of 80 was assumed. This is a conservative estimate, since enrollment has reached about 95 in previous studies of drug and alcohol use or mental illness, conducted by AMHF. Based on these assumptions, about 570 patients in the public clinics and 520 in the private clinics should be enrolled in three months. Loss to follow-up is estimated at 10 at one month, another 10 at three months, and another 10 at six months. At six months of follow-up it is expected to have approximately 370 recruited patients in public clinics and 340 patients in private clinics. This would result in sufficient power to detect the expected decrease in consumption separately in the public and the private sector. If for any unforeseen reason, the estimated needed sample size is not reached in three months, the enrollment period will be extended, and still have the capacity to do a 6 months follow-up on all the recruited subjects. 