Mental Disturbance was an early band of the now legendary Belgian metalcore guitarist Michel Kirby (Deviate, Length of Time, Arkangel, etc.). Formed in late-1987 in Brussels, Belgium, the group recorded one demo as a four-piece (Hard of Hearing), added a second guitarist and recorded another demo, and also appeared on a handful of (mostly cassette) compilations. At some point they scaled back down to one guitarist (Kirby), and original bassist Beastie transitioned into the vocal slot.
It was this lineup that would be credited with the band's lone proper release: a self-titled, five-song 7" issued by French label Alternative Noise in 1990. Expect top-notch crossover hardcore/thrash in the vein of D.R.I. and the like. Heavy, yet sarcastically pissed off and fun, as represented herein by "Living in a Slum," one of my personal favorites—hello slap bass! Speaking of which, apparently Mental Disturbance broke up later that same year when bassist Marc de Backer joined Mucky Pup (he later did some work with Dog Eat Dog as well). Go figure!? (Fun fact: Michel and Marc have now reunited in Wolvennest.)
You can also dig up some Mental Disturbance demo material and a live set on YouTube. More importantly, however, to my surprise, there are quite a few very inexpensive copies of this 7" for sale on Discogs, where I recently grabbed one myself. In fact, I actually just ordered a second, because the listing mentioned inserts, which my first purchase did not contain!