There is a discussion going on now as to whether or not the investment demand for precious metals really matters to their prices, or if the price affects investment interest.
There are some who analyze the precious metals markets only taking into account the industrial demand for the commodities. I think investment demand also impacts the price. However, that idea needs to be tempered. Part of the demand also seems to be affected by significant increases and decreases in prices. To the extent that is true, you could say that prices create investment demand instead of the other way around.
Source: NumismaticNews