Differences between hybrid and MTB handlebars?
 

Are there difference between hybrid and MTB handlebars? Are these interchangeable?

A flat bar is a flat bar. A drop bar is a drop bar.

While they did have different clamp diameters, 31.8 mm has made stems universal.

Modern MTBs will run a wider bar with a short stem, while most hybrids will still run an older school setup of a slightly longer stem and not-as-wide bars

As DD said, they are completely interchangeable as far as fit and components. I will add that true MTB handlebars will likely be stronger and more expensive than identical looking handlebars made for lower level hybrids intended for for casual riding. If you see huge price differences, this is likely the reason. You'll have to decide which type your riding style demands. Also, you need to know the clamp size of your stem. It might be 25.4, 26.0 or 31.8 mm. You can always use shims if the stem is larger than the handlebar clamp area but it's best if the two sizes match (I've used shims and they are a PITA).