[phineastcat]

When I got diagnosed with manic depression, I did some research on my family medical history going back several generations. Many of them through two lineages (my father's mother's family, and my mother's father's family) in my family exhibited symptoms of manic depression, but have no corresponding diagnoses.

Not anything scientific, but it does point toward the fact that destigmatizing mental illnesses and our better understanding of them is leading to more diagnoses, not anything else. Everyone's quick to forget how horrifying psychiatric care in the US was up until quite recently.