In case anyone is wondering if Quick Cast reduces the damage interval of channeling spells, it doesn’t. At least not for Psychic Pressure.
However, the 50% magic damage amplification from attributes does apply.
Since I couldn’t find anything regarding the topic, I tested it myself with my c3 wizard -> c1 psychokino.
Was having such hope that the combo of Quick Cast + Psychic Pressure dealing insane amount damage, but well…