Linkin Park guitarist Brad Delson, Blackbear, K.Flay, Deftones lead vocalist Chino Moreno, Machine Gun Kelly, Ross Golan, Kevin Hissink (Boonn), and Grandson helped write some songs, though most were written by Shinoda.

On January 25, 2018, Shinoda revealed his second project as a solo artist with the release of the Post Traumatic EP, consisting of three tracks focusing on his feelings after the death of his Linkin Park bandmate and longtime friend Chester Bennington, who died by suicide on July 20, 2017.

[9] In early March, he unexpectedly announced that he was working on a solo album, inviting fans to meet him that day in Los Angeles to hear a new song and to join a music video.

"[11] In May 2018, Shinoda unveiled the tracklist, which included collaborations with Blackbear, Grandson, K.Flay, Machine Gun Kelly, and Deftones frontman Chino Moreno.

Hopefully as I go, the lighter days become more frequent.Shinoda wrote most of the music on the album himself, but songs like "About You", "Make It Up as I Go", "Lift Off" and "Running from My Shadow" were written with co-writers including: Brad Delson, Blackbear, K.Flay, Chino Moreno, Machine Gun Kelly, Ross Golan, Kevin Hissink and grandson.

A leftover song from Linkin Park's last album One More Light, "Place to Start", features percussion from band member Rob Bourdon.

I'd make all these things with no intention of putting them out, but just diving into some of the ideas that were already in my head.The music was recorded at Shinoda's home studio The Stockroom in Los Angeles.

Shinoda was helped by Frank Maddocks, who has previously contributed to artworks for Deftones, Green Day's Revolution Radio and Linkin Park's One More Light.

The soft-cover art book was available bound with a clear O-card slipcase and includes the CD tucked inside a baby jacket.

Neil Z. Yeung of AllMusic praised the album, stating that "While Post Traumatic takes an emotional toll, it ultimately instills feelings of hope and the idea that things can get better.

[1] Dave Simpson from The Guardian, noted that although Post Traumatic contains "flaws", he said that "its raw emotion is unusually touching and many will find it a source of tears, strength and comfort", giving 4 out of 5 stars to the album.