When Vienna finished its subway system in 1978, a lot of people started to commit suicide by throwing themselves in front of the trains. Suicide attempts numbered nearly 40 per year. Obviously the media reported about this, causing the increase of attempts. This is caused the "Werther effect", after the protagonist in the book of Goethe. Psychiatrists started to work with the journaists and a stop on the suicide reports were implemented in 1987. This resulted in a drop of suicides to roughly 6 per year.
Source: Nicholas Christakis & James Fowler, Connected, 2010, Harper Press