TheSavage

You could take a class or two in any are you think you might not have an equivalent background to someone with an MPH (ie, epidemiology courses, maybe biostatistics, general public health, etc?). You're right that a whole extra masters isn't worth the time and money - you're better off focusing on relevant work/research experience.

Also check out Columbia's epidemiology program (which will give you important skills/tools for public health research) as the department has a really good psych epi focus (check out Dr. Schwartz, who is a fabulous second semester epi professor).