The claim that installation of blue streetlights in Japan caused a reduction in suicide rates is unproven by research since experts say there’s no conclusive evidence that blue lights will prevent suicide and the effectiveness of the blue lights in this regard has not yet been proven. The limitation for the study in 2013 showing decrease in suicides is that the analysis relied on data from a single railroad company and it did not examine the underlying suicide-mitigation mechanism of blue lights.
- In 2014, Keio University color psychology professor Tsuneo Suzuki stated that effects have not been conclusive for research that proves that blue lights will dissuade people from killing themselves.
For instance, for a period of time, people talked about the color blue as having a calming effect on the mind. There have been attempts to test this theory, such as making running tracks blue to aid concentration, or installing blue LED lights at railway stations to prevent suicides, but the effects have not been conclusive.
Officials from Tokyo-based private railway company Tokyu recently paid Keio University’s Suzuki a visit to seek his advice about the psychological effect of colored lights. Forget about it, he said, not least because the lights would be switched off during the daylight hours. “I told them that I understood their concerns but that they won’t solve a deeply rooted societal problem like suicide by putting up lights,” he recalled. “If you showed that it was possible, you would probably win the Nobel Prize.”
Per Kenji Hall in 2009, Tsuneo Suzuki stated,
Train operators are desperate to do anything that will bring down the number of suicides. But there’s no research that proves that blue lights will dissuade people from killing themselves.
Also, East Japan Railway Company spokesman Koji Takano had said in 2009 that the decision to use blue LED lights wasn’t based on any researchers’ specific findings.
- A 2014 research article titled "Reconsidering the effects of blue-light installation for prevention of railway suicides" stated that "The exact proportion of nighttime suicide attempts at the ends of railway platforms was not calculable. Nonetheless, the proportion of suicide attempts that is potentially preventable by blue lights should be less than our conservative estimate."
A recent preliminary communication suggested that the calming effect of blue lights installed at the ends of railway platforms in Japan reduced suicides by 84%. This estimate is potentially misleading from an epidemiological point of view and is reconsidered in the present study. The installation of blue lights on platforms, even were they to have some effect in preventing railway suicides at night, would have a much smaller impact than previously estimated.
Limitations: The exact proportion of nighttime suicide attempts at the ends of railway platforms was not calculable. Nonetheless, the proportion of suicide attempts that is potentially preventable by blue lights should be less than our conservative estimate.
Another research article published in the same journal in 2014 reported no measurable increase in suicides at neighboring stations, suggesting the installation of blue streetlights did not simply inspire potentially suicidal people to seek out another platform on which to end their lives. While some limited data suggests a minor effect has been observed areas where blue streetlights have been installed, there is no documentation establishing a definitive causal connection between blue streetlights and reductions in suicide.
Per Abimbola Farinde in 2014, seasonal affective disorder (SAD) is recognized as a type of depression that occurs in the affected population on a recurring annual basis and there has been evidence that a much less bright blue light may be all that is necessary to combat SAD.