Receiving a treating as with 〜れる

チノ:

「でもココアさんは味(あじ)の違(ちが)いわからないじゃないですか」

“But you don't know the difference in taste, right?”

「ただのカフェイン中毒(ちゅうどく)ですよ」

“That makes it just a caffine addiction.”

ココア:

「中毒(ちゅうどく)扱(あつか)いされた…」

“I got treated like an addict...”

Key Points

1. 中毒(ちゅうどく)扱(あつか)いされた = “I got treated like an addict”

   • 扱(あつか)い after a noun means treating, labeling, or classifying someone as that thing.

   • Cocoa is reacting to Chino’s カフェイン中毒(ちゅうどく) comment as if Chino has labeled her an addict.

2. Ⓐ扱(あつか)いする → Ⓐ扱(あつか)いされる

   • Ⓐ扱(あつか)いする means “to treat someone as Ⓐ” or “to regard someone as Ⓐ”.

   • The receptive form Ⓐ扱(あつか)いされる means “to be treated as Ⓐ”.

3. された is the past receptive of する

   • する becomes される, and in past tense された.

   • The sentence focuses on Cocoa receiving the treatment, not on Chino as the person doing it.

4. Omitted subject: Cocoa is the receiver

   • A fuller version would be 私が 中毒(ちゅうどく)扱(あつか)いされた or 私は …, depending on emphasis.

   • The line leaves 私 out because the reaction is thought by Cocoa herself.

5. Do not split the さ as sentence-ending さ

   • In 扱(あつか)いされた, the さ begins された, the receptive past of する.

   • The structure is 中毒(ちゅうどく)扱(あつか)い + された, not 扱(あつか)い + さ.