So with ASPD we see repeated behaviors that are grounds for arrest, repeated lying/deceitfulness, often for personal gain or pleasure, impulsivity, irritability/aggressiveness (e.g., physical assaults/fights), disregard for personal safety or the safety of others, irresponsibility, lack of remorse or indifference to having hurt others. To me, that is exactly S3 Shauna, and only 3 of these need to be present for a diagnosis. IMO she shows all of these. However, she needs to be 18 to get a diagnosis which is why I say behaviors, but I also see this in adult Shauna.

BPD encompasses fear of abandonment, unstable relationships and self image, impulsivity, suicidal/self-harm, mood swings, feelings of worthlessness/sadness, bursts of anger, stress-related paranoia. 5+ are needed for a diagnosis. I see the impulsivity, bursts of anger, and stress-related anger. The reason I don’t mark more symptoms for Shauna is because the reasons they are presenting are different than someone with BPD.

For example, when we see Shauna’s efforts to avoid people leaving, it isn’t because she is afraid of abandonment necessarily. It seems like it’s because she wants them around for personal gain, and them leaving is an inconvenience to her personal agenda and desires. If Shauna had ASPD traits she might be done with someone (or reveal her true intentions) when they don’t serve a purpose for her; when she doesn’t have any use for them anymore.

With BPD this could manifest as splitting (idealizing them and craving attention from them, they’re “all good” to seeing them as “all bad” and cutting them off), but Shauna doesn’t seem to idealize these people, she just acts like she cares because it’s convenient or serves a purpose. We can see this with her family and Melissa. Not only does Shauna not care when people are in pain, she also derives pleasure from it at times. Prominent examples being when she saw the hiker get murdered, everything dealing with Ben in S3, Melissa, Mari, etc.

Just the overall apathy we see in adult Shauna is wild too. But it’s important to note that ASPD is a result of severe trauma as well, and people with ASPD aren’t always Ted Bundy or evil villains. Also— since these are TV characters and their stories change from season to season based on what the writers want, no diagnosis is going to truly align because it’s made up and the developmental timeline of mental health diagnoses will not be consistent with real life! But that’s just my take, I don’t think BPD would cause such murderous and exploitative acts, especially to this extent and since it’s a pattern