Fans of Rumiko Takahashi’s work are no strangers to her lead heroines having tsundere personalities. This is true of her iconic heroines like Lum Invader from Urusei Yatsura, Akane Tendo from Ranma ½ and Kagome Higurashi from Inuyasha.
While Maison Ikkoku’s Kyoko Otonashi can also be described as tsundere, she has one thing noticeably different from those heroines: Kyoko is a young widow navigating through adult life without the support of a loving, nurturing family. Given her relationship with her parents, her childhood experiences and how this informs her adult relationships, it can be better argued that Kyoko has symptoms of Borderline Personality Disorder.
Kyoko's Life Is Defined By Instability
One of the hallmarks of Borderline Personality Disorder (BPD) is that it's a Cluster B disorder characterized by instability. This includes having an unstable self-concept, unstable relationships, unstable moods and difficulty controlling emotions. Throughout the Maison Ikkoku manga and its subsequent anime and live-action adaptations, Kyoko struggles with all four of those things.
While Takahashi doesn't dive too deep into Kyoko's upbringing, both the flashbacks and present storyline make it clear Kyoko doesn't have a stable relationship with her parents. Between the two, she manages to get along slightly better with her father. Unfortunately, he still sees her as his "little girl" and hasn't come to terms with the fact she's already an adult. As such, Kyoko's father is not supportive of her decision to marry and is harshly critical of the men in her life.
Kyoko's relationship with her mother Ritsuko is particularly troublesome. To start with, it's characterized by Ritsuko's frequent violations of Kyoko's personal boundaries and autonomy. Too often, she is seen attempting to control her adult daughter's life by making major decisions about her employment and the men she feels she should marry. In the latter case, she consistently pressures Kyoko into accepting a marriage proposal from her wealthy tennis coach, Shun Mitaka.
This unstable relationship significantly informs Kyoko's self-concept. As someone who is constantly criticized by her parents for the choices she makes in life, she rarely receives any meaningful support from them. This naturally takes a nasty toll on her self-esteem and she is unable to define her own self-worth. As such, she does not manage to develop an individual identity, which leaves her vulnerable to getting into codependent relationships.
Kyoko Has An Intense Fear Of Abandonment
Another major hallmark of BPD is an intense fear of abandonment, which is also Kyoko's greatest fear in Maison Ikkoku. In fact, so much of her emotional instability is linked to this fear of real or perceived abandonment. It also informs Kyoko's extreme black-and-white thinking and her difficulty trusting others, which are also symptoms of BPD. This aspect of her character is more strongly explored in her relationship with Yusaku Godai.
It's clear throughout Maison Ikkoku that Kyoko is romantically interested in Yusaku in part due to the attention he gives her. The other part is due to her persistent feelings of emptiness as a result of losing her husband, Souichiro Otonashi, and having low self-esteem. Despite this, Kyoko -- for most of the series duration -- never communicates her feelings to Yusaku. She does, however, consistently get angry at him whenever he spends time with other female friends like Kozue Nanao.
While Kyoko's anger is inappropriate, it still comes from a place of perceived abandonment as she finds Yusaku's relationships with other women threatening to her own with him. This fear is especially intensified by Yusaku's inability to communicate his personal boundaries, which leads him to agree to dates with women he has no romantic attraction for. He's also not beyond thinking about sleeping with other women as a way of building sexual experience if Kyoko ever decides to take their relationship to the next level. This proves to be a major trigger for Kyoko's explosive emotions.
In one particular Maison Ikkoku episode, where Yusaku's roommate Akemi Roppongi was left at a love hotel by her date without paying the bill, she called Yusaku to pick her up and help out with the bill. He acquiesces to Akemi's request, but in helping his roommate out, Yusaku is seen by his friend Kozue. This encounter causes her to mistake his presence with Akemi at the love hotel for something else. When Kozue communicates this encounter to Kyoko, she explodes with anger at both Akemi and Yusaku.
Kyoko's Emotional Instability Leads To Impulsive Behavior
Difficulty in controlling emotions is a primary reason Kyoko is unable to form stable relationships. It's also a major source of impulsive behavior for Kyoko, another known symptom of Borderline Personality Disorder. Whenever she gets angry at Yusaku, her impulsive behavior tends to include making scenes in public spaces, hitting him with insults, and even making decisions for him on a whim.
At one point, a misunderstanding with Yusaku led Kyoko to take a holiday at select locations throughout Japan on an impulse. She also left behind an itinerary in hopes of prompting Yusaku into following her around the country. The first time Kyoko summoned the courage to express her feelings for Yusaku by kissing him, she promptly quit her job after Kozue expressed romantic interest in him as well. Despite the impulsive nature of her quitting, her own manager (who also happened to be her former father-in-law) still hired a new person to temporarily fill her position.
Kyoko's most impulsive act in response to a fight with Yusaku happened exclusively in the Maison Ikkoku manga. After the love hotel incident with Akemi led to a major fight between them, Kyoko attempted to make up for her behavior by offering to sleep with Yusaku at a love hotel. Yusaku didn't feel this was the right solution to their relationship problems, as he wanted to make love with Kyoko for honest reasons. As expected, it proved to be an embarrassing first sexual encounter for both.
While Kyoko Otonashi has many of the prominent symptoms of BPD throughout Maison Ikkoku, she does eventually become aware of her behavioral patterns and actively works on changing them. She does this by learning to trust Yusaku better and by removing herself from emotionally triggering situations. Though she still struggles with an unstable self-concept, she does work on having a better relationship with her parents and being more empathetic toward others.