Drug laws have changed over time in many countries. In some cases, possession of certain drugs has been made a criminal offence, while in other cases it has been decriminalised
The Portuguese case - From 1930's to 1975 Portugal had been ruled by a right-wing dictatorships as a 'closed' and strictly regulated society.
After revolution in 1975 it became a democracy and increased influx of drugs and soon Portugal had the highest rates of heroin addiction in Europe
From 2001 the possession of drugs was changed from a crime to a civil offence in Portugal
The thinking behind decriminalisation was the drug use should be regarded as a public health issue aimed at harm reduction, rather than an issue for the criminal justice system
Since the change in law drug use has fallen sharply
the rapid growth in the scale of drug addiction in Portugal after 1975 led to calls for drastic action to tackle the problem
It was also felt that, as a relatively poor country, the new law would reduce the cost resulting from drug use and one source points to a saving of 18%