Complex sentence: Dorion later worked toward the treatment and prevention of drug addiction, founding the intervention centre "De l'autre côté de l'ombre" in 1996 and remaining as its president and director until 2007.
Split into simpler sentences: Dorion later worked toward the treatment and prevention of drug addiction. He founded the addiction and prevention centre "De l'autre côté de l'ombre" in 1996, and remained its president and director until 2007.