(Warning: this post contains spoilers from Episode 7.) On Netflix's new series 13 Reasons Why, Clay Jensen listens to several cassette tapes that his classmate Hannah Baker left behind before committing suicide. As Clay goes deeper and deeper into the tapes, learning what, and who, led Hannah to decide to end her life, it's clear the tapes are beginning to take a toll on his own mental health and his parents are becoming concerned. It turns out Clay used to be plagued with nightmares in the past, which begs the question: why does Clay have nightmares on 13 Reasons Why?
Early on in the show, Clay had a nightmare that he was at the school dance with Hannah and though things were going well for them the dream, it turned bad when Hannah stepped away, revealing she was bleeding from her wrists. In Episode 7, it's revealed that this is how Hannah ended her life, which is probably why Clay's nightmare took form in this way. However, in the same episode, Clay's parents made it clear this isn't the first time Clay's had bad dreams.
Clay's mom is very concerned about her son and even tried to get him to take some kind of medication that he'd been prescribed in the past. It isn't clear what kind of meds they are or why Clay was given them in the first place, but it seems like it may have to do with a different tragedy from his past, especially because his mom also suggested that he should start seeing his therapist again.
Later, Clay's dad then asked Clay point blank if he was having nightmares again and makes it clear that if Clay is, it's OK if he needs to talk to someone "that doesn't share your DNA" about it. However, Clay assured them that he's fine even though it's clear he is not.
His nightmares have begun to seep into his waking hours. At the basketball game, he saw Hannah lying on the court bleeding out and even yelled out for the game to be stopped, thinking what he was seeing was real. This continued to happen to him throughout the episode, where he saw and heard things that weren't actually there. Clay finally snapped towards the end of the episode when he called out practically everyone for not caring about Hannah until it was too late.
While Clay makes valid points it's also clear that he's reaching some sort of breaking point due to his grief. Let's just hope that he's able to get these nightmares under control and find a way to cope with this tragic loss.