Somewhat. There's multiple types of foam board used for insulation in buildings. The most common types are EPS, XPS, and polyisocyanurate. EPS and XPS are Expanded and eXtruded PolyStyrene, respectively. Both are closed-cell foams.
EPS is styrofoam, and is made by putting a bunch of polystyrene beads in a container, and then heating it up so they expand into a big block either in the desired final shape, or later cut into the desired size and shape.
XPS is foamed up with a blowing agent, previously an hyrdoflourocarbon gas (I don't know what's used currently), and then extruded into its desired shape.
Polyiso is its own animal, but I know little about it, other than it's not polystyrene.
EPS is styrofoam, and is made by putting a bunch of polystyrene beads in a container, and then heating it up so they expand into a big block either in the desired final shape, or later cut into the desired size and shape.
XPS is foamed up with a blowing agent, previously an hyrdoflourocarbon gas (I don't know what's used currently), and then extruded into its desired shape.
Polyiso is its own animal, but I know little about it, other than it's not polystyrene.