Boogiepop wa Warawanai, Shinreigari Recommendations
Both very dark series that are psychological as well.
Very similar creepy atmosphere and sirious history theme background. Boogiepop darker than Hound, more chaotic and mystical.
Dimly remembered nightmares, eerie occurrences, and a sense of something sinister happening that you're never quite let in on; though Ghost Hound is still airing, it looks as if it's got ample-enough mind candy to keep you thinking until the very end, as well as a few chills to keep you occupied - just like Boogiepop Phantom.