Hi Bill. If I understand you correctly, you are asking if Topaz Studio will open the individual layers in created in a layered PSD or layered TIF file. Studio is able to open both PSD and TIF files, but only the flattened images from those layered files, not the individual adjusted layers.
However, if you start in Photoshop, duplicate a layer, send that layer to Topaz Studio, it will return you to Photoshop which you will now have two layers to save in a desired file format.
If you are using Topaz Studio as a standalone, you can open a flattened PSD or TIF file, make adjustments in Studio then you can save in Studio's proprietary format (like Adobe's PSD) by saving as a TSP file, which will allow you to go back and re-edit the image in Studio.