This article is not available in English yet so I'll translate the important bits with the poor help of google translate:
Special Researcher Martti Lehtinen at the Legal Policy Research Institute says that they are going through the medication history of everyone who committed murder or manslaughter between 2003 and 2011. More than a thousand perpetrator medications compared with a control group of approximately 10 000 people.
- The study is in the preparatory phase and it is intended to investigate this matter thoroughly. We have a unique opportunity to do that in Finland because our people are so thoroughly registered, says Lehtinen.
The survey is conducted as a collaboration between Professor Jari Tiihonen and Legal Policy. Lehtinen says there is reason to look more closely at the possible link between drugs and violent crime because some patients become afraid and stopped taking their medications.
The first research results are expected this year.
Article continues to say they're looking into this because some patients got scared and stopped taking their medication!
Source if foreign language, bt source of my source is the Finnish News Agency