Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Time course of individual craving scores observed in the placebo (s) and smoking (d) periods with the estimated median curves (solid lines). The median value of the observations has been estimated at each time point and a spline function has been used connect these points.
