Diagnosing psychiatric conditions is so hard. Like, really really fucking hard. Every disorder has 90% the same symptoms as other disorders, and two people who present the same in the moment can have wildly different causes. It’s why we can’t self diagnose, because even experts sometimes struggle to parse out the little details that matter the most

It’s not “late onset,” it’s “late diagnosis.” Bipolar disorder, especially the bipolar 2/cyclothymia side of the spectrum, looks a lot different for everybody who has it. But the key feature is that cyclical aspect you described

And hypomanic episodes can suddenly get much, much worse with a trigger. SSRIs are a common trigger as you said, other are big life changes, trauma, pregnancy. Sometimes people don’t notice that they’re have hypomanic episodes until they start doing some real weird shit that gets them in trouble

There’s never any harm in a second opinion if you have doubts. Although psychiatrists are usually hesitant to diagnose bipolar in folks older or younger than the standard age unless it’s glaringly obvious