 "Sweet but Psycho" is a pop, dance-pop, electropop, and synth-pop song, which is inspired by music in the 1980s.According to the sheet music published at Musicnotes.com by Hal Leonard LLC, it is based on common time, the tempo is 137 beats per minute (BPM), and is played in the key of D major.Max's vocal range spans from the low note A3 to the high note of D5, while the song is constructed in verse–chorus form.