I am planning on attending Judson University and I would like to double major in Biology and Psychology and minor in Intercultural Studies. I was wondering will this be doable? Can anyone tell me how difficult it is to get a minor along with two majors? Is it done very often? I would like to become a geriatric psychiatrist if anyone was wondering.
Yeah it’s doable. It’s also pointless. It’s not going to increase your jobs odds at all, you’re just going to stress you out and possibly be detrimental if you mess up due to the insane workload. But hey, I’m imaginary, so do what you gotta do.
How easy that will be depends entirely upon the college. I have no idea how easy it is to do a double major at Judson. You might want to e-mail someone there and ask them.
I know my middle son opted for double majors (Bio, Brain & Cognitive) and double minors (Psych, American Sign Language) at his school and it wasn’t difficult at all, but his school has very few requirements for “other” classes, so taking what he wanted was easy. Many students opt to double or even triple major there.
He was also pre-med too.
You don’t have to major in something in order to study it. Your major will have a structured list of courses, often in a sequence of increasing difficulty, that’ll form about 1/3 of your total courses. You’ll have 12-15 required classes. You’ll thus have quite a few classes you choose freely, in any subject for which you may have taken the pre-reqs through gen ed or core classes. You could take bio major science classes for gen ed instead of "non major"gen ed, major in Psychology, add a couple upper-level biology classes that interest you that you can take thanks to the bio/gen ed combo, and add some Intercultural Studies classes. 
2 majors and a minor will most likely be a hard row to hoe if you want to graduate in no more than 4 years. Don’t bite off more than you can chew.
This is the kind of question you will want to discuss with an academic advisor. My S just graduated from a liberal arts college with a double major and a minor. However, he entered college with a lot of AP credit, and his school didn’t have onerous distribution requirements. My D graduated from a different liberal arts college, and her distribution requirements were a lot more demanding, and her school didn’t grant AP credit in most situations, or even transfer credit. She had taken a couple of college courses while in HS but her school did not accept the courses.