Does the fifth precept refer exclusively to chemical stimulants? The fifth precept is 


  I undertake the training rule to abstain from fermented drink that
  causes heedlessness


but I have read interpretations that translate it as


  I undertake to abstain from intoxicants


Are there any references in the Buddhist scriptures about the fifth precept having a broader interpretations that refer to intoxicants of different forms - not just chemical stimulants? 

I'm interested in views of any schools as I imagine the interpretation of the precept may be different between them. I'm also interested in any references to more modern teachers who take this broader approach if anyone knows of them.
A modern teacher who takes a very broad approach is Thich Nhat Hanh. I became familiar with his "Five Wonderful Precepts" at a Seon temple where his translation of the precepts is used regularly. This is his translation of the Fifth Precept:


  Aware of the suffering caused by unmindful consumption, I vow to cultivate good health, both physical and mental, for myself, my family and my society, by practicing mindful eating, drinking, and consuming.  I vow to ingest only items that preserve peace, well-being, and joy in my body, in my consciousness, and in the collective body and consciousness of my family and society.  I am determined not to use alcohol or any other intoxicant, or to ingest foods or other items that contain toxins, such as certain TV programs, magazines, books, films, and conversations.  I am aware that to damage my body or my consciousness with these poisons is to betray my ancestors, my parents, my society, and future generations.  I will work to transform violence, fear, anger, and confusion in myself and in society by practicing a diet for myself and for society.   I understand that a proper diet is crucial for self-transformation and for the transformation of society. 


These are from his book "For a Future to Be Possible: Commentaries on the Five Mindfulness Trainings"

From "The Mindfulness Bell" newsletter, dated Spring/Summer 1990, Thich Nhat Hanh gives an in depth interview about his translations of the 5 precepts (which were in a slightly less detailed version back then). 


  Someone who practices the Fifth Precept could not say "This is my body, I can do anything to it. I have the right to." They cannot say that because they know that their body belongs to all their ancestors, themselves, and the future generations.


He talks about the interconnectedness of all things; how the grain used in the production of whiskey and meat can lead to starvation in the world when people don't have enough grains to eat. That particular idea may be arguable to some. But I think his statement below (also from The Mindfulness Bell) is really a key point for those who aren't quite ready to accept the Fifth Precept: 


  So mindfulness is the base of all precepts. Drinking a glass of whiskey with mindfulness is already practicing the precepts, because if you drink with deep mindfulness, you will live with the reality of the world and you will stop drinking very soon.