Elements of Gothic Literature
1. Nighttime Action
2. Supernatural Events
Sometimes the protagonist is just insane, but the book portrays her hallucinations as real (because it is from her point of view), leaving the reader to question whether the things she was seeing were real or fake.
3. Intense Emotions
Very often, the character is somehow socially isolated, and is prone to irrationality or insanity due to intense loneliness and a lack of exposure to healthy strains of thought. She may be driven to attach herself, often romantically, to people she thinks she shares a bond with because she is desperate for human interaction.