Starting from the social network existing before incarceration, we show the great importance of kin relationships (spouse, girl friend, parents) as sources of support during detention. The defense lawyer plays a very significant role as well. Within the prison, the other detainees and the staff of the medical service play a very significant role in providing help and support. Contrary to our initial hypothesis, the best supported prisoners are not necessarily best off with regard to mental health. Nevertheless, the feeling of having been supported is in general rather favorable to mental health, but paradoxically, is also associated with greater medicalization. Relations between social supports and mental health are complex and often contradictory: the meanings of social support are not the same for the different subjects of this quite heterogenous population. Kin supports and help from the defense lawyer are clearly beneficial for socially well integrated individuals. In contrast, supports of whatsoever kind appear to have no positive effect on persons already socially and penally stigmatized before their incarceration. Finally, drug addicts having had regular visits from kin express suicidal thoughts much less frequently and are less inclined to become overly medicalized. (Author summary)