I've never told it to anyone, but your thread made me think of these times when I walked kilometres during dark hours just to collect stones to eat them later. Felt like I was doing something illegal, I was so embarrassed of it, but I don't care at all anymore. I had a serious addiction for few months at least. Not usual stones that you can't swallow, but soft stones made of grout and cement (?) or something that melt in your mouth. Now I'm reading that I had a psychological disorder Pica. Eating paper is also one form of that disorder if it happens longer than one month. I also ate a lot of snow and ice at some point. I'm glad it happened more than 10 years ago and I don't feel the urges anymore, I find it quite disgusting now.
Pica is a psychological disorder characterized by an appetite for substances that are largely non-nutritive, such as ice (pagophagia); hair (trighophagia); paper (xylophagia); drywall or paint; metal (metallophagia); stones (lithophagia) or soil (geophagia); glass (hyalophagia); feces (coprophagia); and chalk.