Psycho-reflective Screen

Protects you from 15% of combat damage.

This is a skill you can use through the whole game. It's really long lasting, and coupled with it's very low Psi point cost, you should automatically cast this every time you enter a new area. You'll want to pick this skill during your 3 year training at the start if you choose the O.S.A. as your career path.

Neuro-reflex Dampening

Eliminates all weapon kickback.

I've learned, from much use of weapons in this game, to control kickback that weapons have. If you too can manage to control the recoil, then there's not much point in having this skill. On the other hand, if you are just having a tough time getting the hang of recoil, this is a good, low cost method of eliminating recoil all together.

Kinetic Redirection

Pulls an object toward you.

This skill has minimal use. There's at most 1 or 2 times where this skill is the only way you can get an item. Skip it and save the upgrade modules for something else.

Psychogenic Agility

Increases your Agility by 2.

Some people would argue differently, but I really like this skill. It lasts for a really long time and costs only 1 psi point. Because I'm an agility whore, I prefer to dodge attacks and flank enemies rather than take them head on, so every point of agility I can get is a god-send.

Psychogenic Cyber Affinity

Increases your CYB by 2.

I recommend this to any player trying to go through the game as a hacker, the 2 CYB points are invaluable assets. However, if you don't hack very often, there's not much point to this skill.

Projected Cryokinesis

Launches a heat-draining projectile at a target. Higher PSI increases damage.

This is only mildly useful throughout the game. It takes a long time to charge it, far longer than any other attack in the game. Add on to that the fact that it really isn't a very strong attack, and you've got a pretty poor weapon on your hands.

Remote Electron Tampering

Makes active alarms time out faster.

I can't think of much use for this skill. With the fact that simply right clicking on any security console deactivates the alarms completely and for free, there's no point in having this.

Anti-entropic Field

While this discipline is active, your ranged weapons cannot break, and their condition will not degrade.

This is an alternative to using the maintenance skill. Personally I'd prefer the maintenance skill because it allows you to put more energy into your energy based items, armor, and weapons.

Adrenaline Overproduction

Increases hand-to-hand damage by a factor equal to PSI.

This ability multiplies melee damage by a factor of PSI. For example, if you have a PSI of 6, all melee damage will be multiplied by 6. With a decent melee weapon, strength, and this skill, you can do insane amounts of damage.

Neural Decontamination

Shields you from 80% of radiation damage.

Use the BioHazard suit instead and spend the upgrade modules on something better.

Cerebro-stimulated Regeneration

Regenerates lost hit points.

This skill is invaluable. Of all the psionic user's skills, this is the most powerful. A lack of Health Hypos or Med Kits shouldn't be a problem if you have this skill.

Psychogenic Strength

Increases your Strength by 2.

The biggest use for this would be for hand to hand combat. This doesn't give you nearly the damage bonus that Adrenaline Overproduction can, but the benefit of this over Adrenaline Overproduction is that this can be used later in the game when your inventory space is getting crowded.

Recursive Psionic Amplification

Increases your Psionics by 2. Psi point costs are doubled while active.

In my opinion, the 2 extra Psi points aren't worth the double cost. Just use the skill twice for the extra benefit instead of getting this.

Localized Pyrokinesis

Damages all creatures within a five foot radius. Higher PSI increases damage to enemies.

I really didn't like this skill until someone on the TTLG boards pointed out some rather enticing info about this skill. First, this skill negates any incendiary damage you would normally take. This means that the really annoying protocol droids on the Engineering bay can't damage you while this ability is active. Second, if you activate this ability first, then the invisibility ability second, you can walk right up to enemies and watch them fall to your feet dead, all while remaining unnoticed. Quite a powerful skill when used right.

Molecular Duplication

Use some Nanites to duplicate one ammo clip or hypo.

This is a useful skill when you're low on an item, but the nanite cost is expensive, so be careful.

Electron Cascade

Recharges a single charged item or weapon.

This can be an invaluable lifesaver, or a complete waste depending on how you're playing the game. If you're using energy based weapons, armor, or items, this skill can be used as a fairly cheap source of power. If you're not using energy based stuff, just skip this skill.

Energy Reflection

Provides 50% immunity to all energy-based damage sources.

50% is a lot of protection, but there's just not enough enemies with energy-based attacks to justify getting this skill.

Neural Toxin-blocker

Shields you from 100% of toxin absorption.

By the time you see the spiders, it'll be too late to use this skill. Just skip it.

Enhanced Motion Sensitivity

Shows the location of all nearby creatures.

Use your god-given skill of hearing instead, and you'll do just as good as with this skill.

Projected Pyrokinesis

Launches a fiery projectile at a target. Higher PSI increases damage.

This, like Projected Cryokinesis has only limited usefulness. The benefit of this over Projected Cryokinesis is that this skill doesn't take very long to charge, and it does more damage as well. Unfortunately, this skill can't damage mechanical enemies, and it can drain your Psi points very quickly. This does come in useful against the Psi Reavers that appear late in the game, though.

Psionic Hypnogenesis

Target non-robotic creature will stand still and docile. If the creature takes damage, the effect ends.

Another ability I had my mind changed on. At high PSI levels, you can put an enemy to sleep with this for over 2 minutes with a single shot, which is such a long length of time that they're basically as good as dead. This skill can be useful against the stronger enemies late in the game. Just make sure you don't hit them by accident and wake them back up.

Photonic Redirection

Renders you invisible to all creatures. Firing a weapon will end the effect.

By itself, this ability is useful for sneaking past strong enemies instead of taking them on. When coupled with the Localized Pyrokinesis ability, this ability becomes invaluable to a Psi user. This is one of the most useful Psi abilities.

Remote Pattern Detection

Shows the location of many useful items, including nanites, ammo, hypos, implants and audio logs.

I've never used this skill, when I do, I'll be sure to write something about it, but as it stands, a keen attention to detail seems like it would better than using upgrade modules on this skill.

Electron Suppression

Immobilizes any robotic target.

Pretty much the same as Psionic Hypnogenesis, but it works only on robotic enemies.

Psychogenic Endurance

Increases your Endurance by 2.

Endurance just isn't useful unless it's permanent. Skip this skill.

Molecular Transmutation

Turns ammunition and hypos into nanites.

Use the item recycler instead.

Remote Circuitry Manipulation

Allows you to hack psionically. Uses half you PSI stat (rounded up) in place of both Hacking skill and CYB stat, and costs psi points instead of nanites.

This will allow you to hack into some of the earlier crates and consoles, and I get it for that, but don't expect to be hacking anything on the Rickenbaker with this skill.

Cerebro-energetic Extension

Turns your Psi-Amp into a powerful melee weapon.

The second strongest melee weapon in the game, but by far the most useful. With Adrenaline on and decent STR you can kill a rumbler in one hit.

Advanced Cerebro-stimulated Regeneration

Regenerates lost hit points.

This skill is just too powerful. Cerebro-stimulated Regeneration can generally refill your entire health bar, and it costs much less than this skill.

Soma Transference

Drains target non-robotic creature of hit points, and adds those hit points to your total.

This is an interesting skill. It takes your enemy's health, and adds it to your own. With that use alone, this ability might have questionable usefulness, but there's several neat things you can also do with this ability. This ability is the only attack that can work through a Metacreative Barrier. That means that you can trap strong enemies behind a barrier, then simply kill them while they pace around helplessly. Also, probably more as an oversight by the developers than a true intention for this skill, Soma Transference can kill the mind of the Many before you kill the protective stars that normally prevent damage to it.

Instantaneous Quantum Relocation

Teleports you to a marked location. If there is no marked location, this will set a marker at your current position. You can clear an obsolete teleport marker by hitting Alt-T.

Mildly useful if you're impatient. More patient people can just walk to where ever and spend the upgrade modules elsewhere.

Imposed Neural Restructuring

Causes a non-robotic target to become hostile toward all non-human creatures.

This is a really fun skill to use and nailing a rumbler with this can really help you out late in the game. Just make sure you hit strong enemies with this skill if you get it.

Metacreative Barrier

Creates a wall of psionic force directly in front of you.

The barrier has a large amount of HP and is useful for blocking off strong enemies so that you can ignore them instead of having to deal with them. An added benefit is that this ability goes hand in hand with the Soma Transference ability. Rather than being stopped by the barrier, Soma Transference works through the barrier, allowing you to drain away an enemies HP while never being exploited to harm yourself.

External Psionic Detonation

Drops a psionic proximity mine. Does no damage to robots, and double damage to psionically sensitive creatures.

This is more of an oddity than a truly useful skill. It's good for setting up ambushes or traps, so that's a plus, but then again, you can always do the same with a trusty ol' shotgun or rifle.

Psycho-reflective Aura

Protects you from 60% of all combat damage.

This is a matter of opinion. Coupled with the Powered armor, you can attain near-immortal levels of protection. Unfortunately, this skill is short lived and very expensive. Use it with care.