I've been using light and sound machines since 92. Note, I do not take any medications for anxiety / depression. I dont suffer from epileptic fits / siezures.

I would think these machines could have an effect on anyone who is not comfortable with closed spaces, strange visual patterns or anything that seriously throws off your perception and can drastically change your brainwave patttern in a short period of time. Outside of perhaps feeling uncomfortable at times, I don't think it would affect you physically.

Note, you should always consult your doctor when using such a device and taking medications.