Treatment of Tourette's Syndrome with Δ9-Tetrahydrocannabinol (THC): A Randomized Crossover Trial - Müller-Vahl, K R; Schneider, U; Koblenz, A; Jöbges, M; Kolbe, H; Daldrup, T; Emrich, H M (Pharmacopsychiatry, 2002)