Looking Pink, Feeling Blue

Twilight paced in circles as Rarity read the letter. "Depression?"

"That's what I said," Twilight said.

"Oh dear. This is quite serious. How could the happiest pony in Equestria have depression?"

Twilight pulled out some books. "I've done some research." When Rarity gave her an 'I'm not surprised' look, Twilight continued, "I couldn't help myself. These books all say that when a pony has depression, usually they don't want anypony to know. Usually, so no one worries about them. Pinkie could be doing that."

"For her whole life? Well, since she was a filly?"

"It's possible. It would surprise me even more, but it's possible. I ask you because I know you had depression as a teenager."

Rarity nodded, and then turned to her marefriend Applejack. "Darling, you would tell me if you had depression right?"

AJ nodded. "A' course. Apple Bloom had depression before she got her Cutie Mark, but we only thought of it that way when she saw a therapist a few months ago. As for me, ah had it when mah parents died." She turned to Twilight. "Ya know, in both cases, we Apples just kinda...let that thing run it's own course. But if Pinkie's has lasted this long...ah don't think ah'm the right pony to be askin'."

"Apple Bloom, huh?" Twilight lifted her hoof to her chin. "Do you two know anypony else who's had depression?"

"Well...Rainbow Dash said she had it for a little while in Flight School," Applejack recalled. "But ah don't think it affected her all that much."

"Fluttershy did as well. She told me once that she saw a therapist many times. She even took medication." Rarity turned back to AJ. "She actually...told you that?"

"Yeah. Ah didn't ask or anythin'. She had too much cider and just kinda...spilled." She snickered. "Pun not intended."

"Well, I'm not going to ask her." Twilight put the books away. "And I don't want to make Fluttershy uncomfortable."

"Maybe you should ask her parents, darling. Or her sisters."

"That's a great idea, Rarity! You two should come."

The marefriends shared a glance before Applejack said, "Twi, ah think this is somethin' you need to do on your own."