The Chop Suey group haven't released an album since 2005's Hypnotize and the 57-year-old singer admitted he became "very passive" in the final days of the group because he was in a "weird place" at the time.
He told Metal Hammer magazine: "I had a very unique relationship with the last few records because I had, to a certain degree, emotionally checked out of the band while making them.
"Because of the push and pull, I became very passive.
"There was music I wanted to bring in that I felt like I couldn't… I was in a weird place.
"I contributed creatively but I didn't… I don't know. I needed oxygen – I felt like there was too much going on."
However, the Sugar singer thinks Hypnotize and its predecessor, Mezmerize, feature "great" songs and making the records still had some "beautiful moments", even if it wasn't a good time in his life.
Tankian said: "Recording (the albums) had its beautiful moments.
"I still think those songs are great.
"But when I think back on it, I also remember that it was a weird phase of my life and that's something I have to be aware of as well.
"We really enjoyed recording the albums at Rick Rubin's place in Laurel Canyon, right across from the Houdini house."
Once the group went on hiatus in 2006, it was "incredibly important" for Tankian to keep working.
He said: "It was incredibly important for me to stay active.
"I was writing songs while on the buss for Ozzfest.
"To a certain degree, I felt I couldn't do everything I wanted to within the realms of the band and that's fine – I don't think anybody can.
"I had a vision for what I wanted to do and wanted to present a new vision, so I wrote the songs separately and ultimately put it out as my first solo record, Elect The Dead, a year after we announced the hiatus."
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