bipolar 1 or 2? my mom and i both have bipolar 2, so i can give you perspective on that as someone who’s experienced it both firsthand and secondhand.
(tw for self-harm and substance abuse going forward)
the thing that comes to mind right off the bat for my mom is how different she is depressed vs hypomanic. she’s a very image-focused person, and i think most of her peers see her as a very driven, organized, put-together person. i see her like that too, sometimes. when she’s hypo, she’s super motivated, will usually go on some kind of exercise regimen/diet and get very fit or lose weight, has a lot more trouble controlling her anger, and (she’s a caterer) will sign on to do a good amount of parties. but i also see her during her depressive periods, where she’ll be practically sedentary for days on end, won’t move from her laptop for hours, won’t cater any parties, will drop her health kick and lament about how out of shape she is (which i am not making any kind of value judgment on, these are her words), etc. she also won’t yell or snap as much, but will instead get really sad over small things: for instance, when i was 17, i drank some vodka from our liquor cabinet (not much), and while she’d previously been fine with letting me drink in moderation, she cried when she found out and was convinced that i was going to become an alcoholic since it runs in our family.
as for my own experience, what comes to mind is that i feel like i sustain myself on waves of energy that crash before i’m ready. i’ll go for months being depressed, sleeping all day, unable to finish my work on time, unable to write anything new, unwilling to make plans with my friends… then one day, things will start to pick up, and for a little while, i finish all my current and missing assignments, i try to sustain myself on like 4-6 hours of sleep a night (if that) and make up for it with coffee and energy drinks, i want to surround myself with people all the time, i want attention from those people, i do potentially unhealthy things to get attention from those people….
i think something to keep in mind, whether you’re writing a bipolar 1 character with mania or a bipolar 2 character with hypomania, is that while hypo/mania is not actually a healthy state of being (i.e. my mom’s anger issues, my self-destructive tendencies), it will often look to others like we’re “doing better.” our affect will be brighter, we’ll be more productive, we’ll be more social, etc. and a lot of the time, it will feel to me like i’m doing better, for the same reasons. but when i’m depressed, i’m not particularly self-destructive, i don’t care enough to be, and when i’m hypo, i am extremely self-destructive. i can think of at least 3 periods in my life when i thought i was “doing well,” or was at least excited to wake up every day, but i was also cutting myself regularly and sincerely threatening suicide like all the time. i have a friend who’s bp1, and every time she’s manic, she makes detailed plans to kill herself (in addition to making detailed plans to travel halfway across the world). this is a goofy analogy, but it would be like if you lived on a little farm where it’s been cloudy and overcast for months, and then one morning there was a brilliant light out your window, and you were so excited! but then you went outside and realized it was because all your crops were on fire.
this is sort of disorganized and ramble-y but i hope it helps regardless haha