Old films involving mind control (say episodes of Gerry and Sylvia Anderson's UFO) often mixed sound cues and music to build up tension.
Only skimmed this thread out of general interest, and I somehow ended up thinking about this all day long when I should've been working.
Not wanting to lose the fruits of my labour, thought I'd throw out them out here for consideration. Might be doubling up what's already covered.
State of mind
Following on a similar line of thought, a soldier's mental state could be simplified as:
Bravery, Morale, Mental State
Bravery is pretty much to morale what armour is to health. It just reduces how severe bad events influence the soldier. Same as it is now. In addition to natural improvements in bravery, it could get small one time bonuses from current rank and how many battles the soldier has seen.
Morale, or should I say the fear and confidence meter. The usual 0 - 100 meter, but should balance at 50%. That's the stable level. When it goes above 50% by way of good events, the soldier gets more confident. When it goes under 50% through bad events, the soldier gets more fearful. So you can have various severity levels such as fearful, slightly distressed, normal, feeling positive or even very confident.
Rather than resetting after reach battle, the morale level at the end of the battle should stick with the soldier. Over time, the score rebalances itself until it is back at 50%. Events outside of combat could influence the current level from time to time, such as promotions/demotions or a surprise birthday party just to make up an example.
Now, we know low morale in X-COM makes soldiers lose control and use up all their TUs with some action or ther. How about the more morale starts to fall, it starts introducing various degrees of involuntary movement from the soldier that occur randomly. Lower level panic, in a way, which is more frequent.
For example, in a highly fearful state, a soldier pointing a weapon might visibly be hold the weapon unsteadily - too afraid to attack. In real-time, this would mean the build up before the gun is fired would be much slower to execute. In TB, more action points would be spent than usual. The worst case scenario being the soldier completely fails to attack and says something like "I... I can't do this!", while wasting time/TUs in the process.
Another example, a soldier can get really jittery and will jump at any may even turn to look at any nearby sudden noises. Say you had a soldier walk nearby across some dry twigs. The twigs crack and the jittery soldier will jerk around to see what made the noise. Things like doors slamming in the distance, or screams out of the darkness.
None of this results in complete loss of control of the soldier, yet. This is where the next stat comes into play.
This works in tandem with morale. It could go from stable, wavering to unstable. Maybe even further down into psychotic. Guess it's the same as the psychosis stat mentioned. This will determine the severity of the involuntary actions taken when morale is low. Also doubles as how suggestive you are to psi suggestions (more on this in a bit). The weaker they are, the easier psi attacks effect them.
When it hits rock bottom while morale is low, the soldier may do something extreme. Like panic, freeze for a moment, go berserk or even flee - being the classic responses. The soldier could even surrender or even curl up into a foetal position and won't move again. These two would mean complete loss of control of the unit, requiring some sort of intervention from others or medical (maybe psi) resuscitation to get them functioning again.
The mind control in the first three X-COM games was way too powerful because you got near-complete control over the alien for the duration of the mind control. So rather than full control, how about instead changing it to suggestion
That is to say, you use your psi abilities to suggest to the alien to do something, and both sides do a battle of wills, and if the alien fails, it does what you want it to do. Say, "attack target", "move to Y", "interrupt what you are trying to do". In effect, it's a milder version of mind control. Throw in the classic panic attack that attacks the morale and the mental state of the target.
An interrupt attack would be almost like a stun command, but not for knocking the target out. Makes the target fail or really mess up its next action. Or you could even make it psionic feedback that makes the target cringe and reel about in pain. Only thinking it is in pain, when it is not. Again, a form of momentarily stunning the unit but not knocking it out. Could be useful for setting it up for a melee attack to really knock it out.
I think psi could be used for a few other support abilities as well. The classic mind probe could be expanded a bit. Such as being able to get an idea of what the alien is doing (idling, on routine patrol, searching for enemy, attacking X, fleeing), or taking a moment to see what it can see, or probing its mind to get a brief glimpse of the location of (where it thinks) its nearest out-of-sight allies are. Could also use it to get information on operating alien thingamajigs to open up shortcuts through UFOs or alien structures in the current map for example.
Other more useful support ability would be to calm targets to normalize (but not boost beyond) the morale and mental state of soldiers that are in a very bad frame of mind. A psi variant of EUTFTD's pain killers.
I also wrote "Placebo" in my notes, which I can't seem to remember what it was about. Probably using hypnosis to make soldiers think they aren't suffering from wound trauma. Oh well.
There was one idea I was playing with for a sword and sorcery type magic system I was fiddling with that can be adapted to psi. A psionic assist ability where multiple weak psi users can channel focus on one psi user to bolster that user's skill momentarily for a combination attack on a strong psi enemy. With appropriate usage/time costs, obviously.
Imagine it like the weapon control systems from Apocalypse, but withpeople. Each person assisting would provide a fixed bonus to the person they are assisting. Say a +10% improvement. Each person that joins into the combo would have their contribution drop in effectiveness. Say by dividing by 2 for each member in the team. The first would get the full 10%. A second person would add +5%, the third 2.5% , the fourth 1.25% and so on and so forth. This way it wouldn't get too overpowering.
Not sure if any of that can inspire any new ideas, but there you go.
NKF, narrow minded fuddy duddy who refuses to let go of the past and will not accept anything newer than 1979.