Answer:
Ostracism
If Glenda is ostracized, it means that she is excluded from social groups is real life, and this rejection leads her to take refuge in her online presence. It is a negative feedback loop because the more she is ostracized, the more obsessed she because with the online world.
Narcissism
If Glenda is a narcisist, she will use social media to showcase how good or superior she perceives herself to be, and how great her life is in regards to everyone else's life, even if in reality, her life is average, and her personal qualities are not extraordinary. This would cause constant cognitive disonance, self-esteem issues, and obsessive social media use.
