In order for rappers to maintain the attention of their listeners, they must be able to effortlessly breathe lyrics that drip with personality. For Substance Abuse, a two-man outfit from L.A., Overproof comes as a vanilla debut that seems ignorant to that fact, with socially-conscious Eso Tre and Subz rapping with skill but delivering in a flat and distracted way. Sticking to an esoteric sound, Substance Abuse mostly succeeds on the production tip, like on the horn-cum-flute lull “No Guarantees” and the piano-washed “Collateral Damage”, but fails when it comes to lyrically spicing them up. Abuse’s delivery on “Night on the Town”, the album’s pasty single, is typical and excessively pushed forward, but Kool Keith fortunately graces the track with a restricted version of his typical off-kilter and comedic persona. While Keith offers a glimmer of light in a plain lyrical landscape, MF Doom and Rasco also drop by to save the listener from ominous boredom on “Profitless Thoughts” and “Everyone’s a Critic” with their signature blossomed personalities. Although they may not have the character to match that of their guests, Substance Abuse does have something to say, as they intelligently critique education on the bubbling “The Graduate” and adrenalized hip-hop on “Sickness”. But even though they sometimes have a righteous message, Substance Abuse may be one of the few rap duos that would benefit from adopting a cheeky gimmick to make their music more interesting.