Any psychological or physiological overdependence
of an organism on a drug. Originally the term was used only for physiological
dependencies in which the drug had altered the biochemistry of the individual
such that continued doses (often of increasing size; See Tolerance, drug) were
required, as is the case with drug opiates and alcohol. However, the line
between the purely physiological addiction and the psychological dependence is
far from clear. The confusion led the World Health Organization to recommend
recently that the term "dependence" be used, with proper qualifiers when drugs
are
involved.
