There's a slump in classroom performance and psychological well-being around 6th-8th consistently-observed enough that it's got one or more names in the fields

There's a slump in classroom performance and psychological well-being around 6th-8th consistently-observed enough that it's got one or more names in the fields of education and psychology ("middle school slump", "middle school malaise", "middle school plunge", et c.) Mention it to a teacher and they'll likely know what you're talking about.