let’s examine Borderline Personality Disorder symptom-by-symptom, while acknowledging that neither of us is a professional psychologist or psychiatrist, and give it our best educated guess!
My short answer is NO, I don’t think so. I once discussed this with another Tumblr user (moselle-green/mosellegreen was her username but she’s not coming up as an active Tumblr user now, so she may have changed her name) and she had some good insight into this, so I’d ask her opinion, as well.
Why do I say no? Because even though Loki exhibits most of the symptoms of Borderline Personality Disorder, if we really examine context, the CAUSE for those symptoms can be found OUTSIDE BPD and in either LIFE EXPERIENCE or ANOTHER disorder. Let’s go through the list:
Frantic efforts to avoid real or imagined abandonment: CHECK. But Loki does this BOTH because of innate predilection, and because learning that he was a member of the Jotun race, literally considered an inferior SPECIES by the racist imperialist Aesir, made him suspicious that Odin’s preference for Thor was due to xenophobic undertones as well as Odin’s admitted planned use of Loki as a political tool to court peace with Jotunheim. Loki has “evidence” that he is thought worth abandoning both because Laufey abandoned him (if we believe Odin’s story of Loki’s origins) as a physically deformed runt, and because Odin hid the implicitly “awful” truth of that “monstrous” heritage from him. So Loki’s feelings of inferiority and abandonment? They come from a legitimate traumatic experience, not just an inborn predilection.
A pattern of unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation NOPE. Loki spent the first 1048 years of his life forming close, stable, meaningful bonds with Frigga and Thor and, to an extent (so long as he was obedient), Odin. Loki was considered both by his parents and by Thor’s friends to be the sane and stable sibling, until everything went south and Thor was banished to Midgard. It’s true that Loki saw Odin in highly idealized terms, and that his adoration for Thor turned on a dime due to his JEALOUSY, but this is again due to his UPBRINGING. Odin reared his sons to be antithetical and used Loki as a sort of grooming companion horse to Thor’s race horse, to train Thor to be the best possible potential king by being his constant companion and competition. Loki has significant COGNITIVE DISTORTIONS because he’s learned that Thor gets what he wants with comparably fewer consequences, and it makes him frustrated and jealous that he makes identical good efforts without identical rewards. Odin is CULTURALLY ASCRIBED the end-all judge of ethical “worthiness” not ONLY by Loki but by ALL of Asgard, so it’s natural that Loki first revered, then loathed, Odin, in such a passionately extreme manner. This is SOCIAL CONDITIONING, not a personality disorder.
Identity disturbance, such as a significant and persistent unstable self-image or sense of self CHECK. But again, WHY? See the first symptom. Response to lived trauma, not a personality disorder.
Impulsivity in at least two areas that are potentially self-damaging (e.g., spending, sex, substance abuse, reckless driving etc) NOPE. Loki is an incredibly calculating, cautious, methodical person, to the extent that he’s frankly clinically paranoid. Does he enjoy chaos for its own sake, and is he a thrillseeker who loves the intellectual jouissance of getting into and out of a deeply dangerous situation using wits and resourcefulness? Yes. But thrillseeking is not unique to BPD. In fact, it could be as easily a symptom of attention-seeking behavior borne of being so long neglected in the past (so again, emotive attachment issues and a bit of the social conditioning), and a mood disorder. This symptom is comorbid with a shitload of other disorders.
Recurrent suicidal behavior, gestures, or threats, or self-mutilating behavior CHECK. But ONLY after he lost his family, his personal identity, his life goals, and exacerbated after he was tortured in a war zone in deep space. So again, trauma response, not a personality defect.
Emotional instability due to significant reactivity of mood (e.g., intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days) CHECK. But I call Post-Traumatic Stress Disorder here. Now, disclaimer: I do believe Loki is a naturally high-strung, sensitive individual, but only to the point of mild neurosis, before horrible things happen to him. See above. The volatility is a hairtrigger coping mechanism that comes LATE in life.
Chronic feelings of emptiness CHECK. But I call Clinical Depression here. Loki only seems to have failed to give a shit after Frigga dies. He’s grieving. That’s not BPD.
Inappropriate, intense anger or difficulty controlling anger (e.g., frequent displays of temper, constant anger, recurrent physical fights) CHECK. But I call Post-Traumatic Stress Disorder here. Loki has what’s called hypervigilance, and temper control issues, ONLY after he’s fallen into that wormhole in space and met Thanos.
Transient, stress-related paranoid thoughts or severe dissociative symptoms CHECK. Once again, however, I call Post-Traumatic Stress Disorder and severe mood disorder.