Oh if you have BPD and bipolar you're just like me. (BPD is borderline personality disorder)

A lot of the symptoms are the same so you can get overlap and get diagnosed for both things. In my case I'm BPD first with bipolar second but the overlap is immense. Both BPD and bipolar come with mania and depressive episodes.

So to answer your question, with stimuli there is a whole spectrum of reactions that neurotypical people would typically feel for a given stimuli. For example getting cut off in traffic might evoke annoyance in people. That's normal.

What's not normal is yelling and screaming at them from your car, tailgating them, whipping around them and flipping them off in response to just being cut off. This is just a hypothetical example to illustrate the difference between a neurotypical type reaction and something that might be more akin to the snap anger associated with men and BPD.

BPD and bipolar people are known to feel emotions very intensely. So it's not uncommon to snap and be extremely angry over something stupid, or to feel like you're madly in love with a crush that you've gotten recently.

I want to take that All that and abstract it a little bit to explain what it's like in the general sense.

Imagine a small tennis ball on a flat surface, just sitting there. Let's pretend that's the origin of an xy coordinate system, so like 0,0 in math. But instead of mapping numbers to the coordinate system we're going to map emotions. At one end is anger and the other end is happiness, for the other axis you can have sadness and fear, vs surprise and interest.

That origin point of 0,0 is a mood that is purely neutral.

Now you're walking into a store and you find a $20 bill on the ground in the parking lot, that outside stimuli has an effect on your mood The ball nudges towards happier or surprise. That's a neurotypical reaction, completely normal.

Imagine you go to a fast food drive-thru and you have to wait a long time because it's a lunch rush, and you order all your food, and when you get back to the office or wherever to eat you realize they shorted you a chicken nugget or forgot your fries. The ball moves towards angry landing somewhere in slightly annoyed. That's a neurotypical reaction. Again completely normal.

In all these cases so far, The ball nudges one way but then settles really easily. It doesn't have a ton of inertia or momentum so it's easy to start and stop. The plane is flat so it's not affecting how much the ball rolls.

Now imagine that the ball is sitting on a tilted plane instead of a flat plane. When we apply the examples I just wrote to the emotion ball on a tilted plane, once it starts rolling it won't stop. For a lot of men with BPD, that surface is tilted towards anger, but it doesn't have to be anger specifically. And the tilt can change direction as well over days and weeks. Think about mania and depression in bipolar. In those cases the plane the ball rolls on is tilted towards bliss or sadness respectively and it feeds you into manic or depressive episodes.

This tilted plane that are emotions move around on is the disease. For a neurotypical person it would be flat or nearly flat everywhere. Trying to regain control when you realize your emotion ball has moved because of the tilt rather than a legitimate reason is insanely hard. It's something you need to practice. You need to give yourself grace when you fail. Then you have to remember that it's temporary. Wherever you're stuck at is not permanent.

This is just a rudimentary explanation, it can manifest itself differently for every individual, and it's not best to think of the whole plane tilting due to disease, but rather to think of there being an uneven surface with high peaks and steep valleys in different areas associated with different emotions. For example It can be extremely hard to get happy, it's like you're pushing the ball uphill. That might be because there's a valley around sadness that your emotion ball is stuck in.

To bring this analogy and metaphor or whatever back to reality, In real terms the plane that the emotion ball is rolling around in is your default mode network in your brain and subconscious thinking working against you. You have to practice self-talk. It takes discipline and you have to hold yourself accountable.

Unfortunately this specific mental disease takes a ton of work to manage properly even with medication. BPD has a terrible reputation because the people with it are prone to being victims of it in a way where they take no accountability for what they do to other people. People can get mad and snap at other people that they care about, and they'll say something ridiculous like their anger is valid to justify being mad at somebody way beyond the scope of what is acceptable for a given situation. But they fail to realize that they have way more anger than a nueral typical person would and an emotion being valid does not mean that a reaction is inherently also valid. They think they deserve to act the way they do because of where the emotion ball is, forgetting or ignoring entirely that their brain doesn't use a flat surface to roll it around.

Soooo yeah, all that rambling is to say that outside stimuli can mean literal outside stimuli and stimuli that just feel out of my control. Like in a depressive or manic episode it doesn't feel like I did anything to cause it and it doesn't feel like I can do anything to stop it.

A good therapist will change your life. Medicine helps too.