Amnesty has repeatedly criticized Sweden for too harsh conditions in the "häkte", where remand prisoners are kept in isolation for extended periods of time.
For some cases prisoners are kept in isolation well over one year. This is a form of low-intensity torture and causes measurable harm to a person's brain and personality - PTSD being one of the more common residual damages done.
And remember, people kept in "häkte" remand prison are suspects, still to be treated as innocent, and frequently exonerated by the courts. They still suffer the harm from the extended isolation.
Sweden in many ways have a good prison system but the extensive and common use of isolation by prosecutors is really bad and a disgrace.
