The mere concurrence of illicit drug use and crime is not enough
to conclude that illicit drug causes crime. According to
qualitative research based in the European Union (EMCDDA - QED)
there is little evidence of crime consequences from the vast
recreational drugs scene across Europe. Alternatively there is
an almost universally identified connection between "hard"
dependent drug use, poverty, prostitution and crime.  Prison
generally does not have a rehabilitative effect. Prisons may
exacerbate harm caused by drug use - this harm may then be
spread to the community outside prisons. There is also an
adverse impact of arrest and imprisonment on employment, that
fact increases the later involvement in crime. Owing to these
and other pressures, interventions have been suggested and
developed as a more effective way of working with problem drug
users who commit crimes.  There is some evidence that law-
enforcement measures as an alternative to prison for drug users
offenders have a positive impact in reducing or