PsyGivesTrauma
 Psyker Build - Warhammer 40k: Darktide 

Force Greatsword (other force swords, or dueling swords... whatever tickles your fancy) I like the IV as it has the stab as heavy 2 (don't need to push attack to access it)
Perks:

• Elite - Most common you see in groups that you can't one shot with special. Maniac Allows you to one shot head shot Mutants with stab. 
• Unyielding - Your staff generally does poor damage to this group of enemies, and the sword stab does fantastic damage

Blessings:

• Shred - it is incredibly easy to keep high peril with Illisi so you can basically always get the buff even out of combat. Shred/Riposte are easy pickups if you don't want to play the peril game
• Riposte - this is a horde clearing weapon, and this blessing will help clear elites and specials in hordes. Uncanny, or Shred are very viable options here.
   

Trauma
Perks:

• Flak - with the increase to damage flak elites can now be one shot with this
• Elite - Maniac is fine, but this helps more with all maniacs as well as Ogryns. Unyielding is okay, but the boss damage on this staff is not great.

Blessings:

• Rending - with the changes to Flak and carapace damage, and the buff to rending this is a great option now (also using shield to keep people from interrupting your charge) Focused channeling is a good alternative.
• Warp Flurry - not as strong as it once was, but you can keep stacks after quelling.
  note Full Charges will massively overkill trash mobs so you can cut your charges around half way to clear hordes.
   

Assail
Spam the ever loving heck out of this to kill ranged elites and specials - you will have so much peril resistance you can blow through all your charges without issues murdering anything beyond reach of Trauma staff. This is also the best way to build up peril for more damage on warp rider.

Telekine Dome
Dome + Sancutary on a 20~ second CD means you will likely be able to have one whenever you need one with a substantial amount of toughness regen.

Warp Siphon
This will provide you with ult cooldown, damage and peril resistance allowing you to spam Assail and your Staff till all heretics are a viscous goo on the Hab floor.
There are enough Elites, Specials, and mobs to get stacks from you don't have to worry about losing your stacks during hordes specially when you have Assail stacks ready.
Inner Tranquility + Battle Meditation means you will essentially have infinite peril as long as you are killing any enemies with Trauma.

A note on Sanctuary, Warp Battery and Mettle (and 15 toughness node) Sanctuary is nice, but can easily be replaced by Mettle as that will proc basically every other hit in melee - this is for a more melee heavy style of play. If you are dropping shield off cooldown, you are unlikely to get 6 stacks of Warp Battery so consider dropping both for Lightning speed.
OR** the 15 toughness node will increase your total toughness (and therefore all toughness regen) by nearly 13% so it is definitely worth considering.