Wangst. Lydia's suicide note is a little over-the-top.
"I am...alone. (Scraps, starts over) I am... utterly... alone. By the time... you read this... I will be gone... having jumped (scratches out jumped) having... plummeted... off the Winter River Bridge."
- Lydia's whole role in the film is a deliberate invocation of this. The Maitlands (and even Betelgeuse himself) essentially talk her out of this attitude, and by the end she's a changed girl.