Can blue colour actually prevent suicides?

It had been reported that the installation of blue-coloured streetlights in Japan and Scotland led to a drop in the rates of suicide and crime in these two countries. The claim dates back to a study done in 2008 and a recent 2015 thread on Reddit popped the question again – What was the role of the colour blue with the decrease in the rates of crime and suicide?

THE COLOUR CHANGE IN JAPAN: The change in the colour of street lights was brought at two locations in Japan – Nara and Keihin Electric Express Railway Co. The changes were brought around 2005.

THE COLOUR CHANGE IN SCOTLAND: Though there wasn’t a valid science or motive behind the street light change in Glasgow, Scotland despite aesthetic, what it resulted in has been worth some research.

RESULTS OF COLOUR CHANGE: What followed the change in the colour of the street lights is that in Glasgow, the number of crimes noticeably decreased. In Nara, the crime rate dropped by 9 per cent while at the railways, which had been a spot for suicide attempts, no suicide occurred since the change in the colour of the lights was made!

RESEARCH: Many research articles have been published in the Journal of Affective Disorders in order to understand why the change in the streetlight colour led to a drop in suicide and crime rates. Their analysis showed that the drop in number of suicides at the railroad company was a whopping 84 per cent. As to why this happened, there have been many theories from experts across the globe.

THE WAVELENGTH OF THE COLOUR BLUE: Another reasoning goes thus: Short wavelength lights, such as blue, can have an effective treatment for disorders that are seasonal, such as a seasonal kind of depression. Such colours have been proven to have a soothing impact on fish and reduce its stress response. However, if it is also valid for humans is not yet proven.