I don't buy this theory. Mine is that there are genetic and environmental factors that cause predispositions to mental illness, and some of us get unlucky with that.

I'm about as far away from emotionally repressed as you can get and had a great childhood. My life is pretty darn good on the overall. That doesn't mean that my body doesn't have an unusual brain structure and imbalanced neurotransmitter levels for entirely different reasons - like genetics. There's more evidence for genetic heritability of bipolar disorder than any other disease. Everyone knew that it ran in families before there was any scientific study to verify that - and verify that they have indeed done.

My advice is to do some research in the scholarly literature before coming up with theories of your own. This is a major step in scientific research, very time consuming, and very important. When you build off the work of others (which has to be carefully peer reviewed and subject to all kinds of criticism before it's even published) you can get a lot further with developing useful theories.