This page is under construction - these are freeform comments on Psionics taken from Q&A with NKF
Psi is a long term investment in Apocalypse. You only earn 3 times your base Psi stats. Hence humans will only ever be useful for low level simple attacks like probes. Hybrids will be your core psi users. Even then they may not be able to do much at the start. They need plenty of uninterrupted practice time in the psi lab before their skills pay off (when I say uninterrupted, I mean: no health loss when the clock ticks over midnight).
Psi may not be immediately useful, but they come into their own once they've built up their stats and can easily strip enemy anthropods or human guards of their disrupter shields in a flash while setting all of their carried grenades to explode on impact with the ground and dropping them.
Can you practice Psionics safely in raids, on operatives of neutral organisations? The only time I've ever got a neutral organization hostile towards me when doing psi practice was when one of my psi troopers mind controlled a gangster then made him jump off the building. When he hit the ground, the gangster was still under my psi trooper's control. The loss in health was attributed to X-COM, and they started shooting. However, if my psi trooper had broken the psi link before the gangster hit the ground, the gangster would've eventually died of critical wounds (or the impact), and the psi trooper would've been free to roam about the map as if nothing happened. A morbid way of killing neutrals and not getting blamed for it.
Stun attacks will have the same effect as you'd get with stun gas or a stun grapple.
Psi attacks require line of sight. Breaking line of sight breaks the link.
Psi attacks expend Psi Energy, a rechargeable resource. In turn based, psi attacks are generally a one time expense. In real-time (RT) mode, you are charged by the attack attempt. If successful, you'll start paying maintenance costs for as long as you maintain the psi link. You can break the link by going out of line of sight or readying another psi attack. Check the mind bender's information panel for the psi energy bar. Stun and panic for example require you to maintain the link long enough for stun increase or morale loss to take place. Probe lets you access the enemy information any time you want as long as the probe is in effect. Mind control lets you control the unit for as long as you want, but is also the most expensive in costs and maintenance. To make the best use of it, try not to spend any maintenance costs at all. Pause the game, control the enemy, go to their inventory and wreak as much a havoc as you can (for example: arm grenade. Right click grenade, then 'drop' the grenade). Once done, break the MC link and let time run and watch the fireworks.
-NKF 00:47, 16 October 2008 (CDT)