How to encourage my players to be reckless and violent.

[frogglesmash]

A little background: I plan on starting a Vampire the Masquerade themed d20 modern campaign, in which the players find themselves turned into fledgling vampires very early on.
In the setting I've dreamed up the process of turning into a vampire doesn't actually make you evil, but it does cause the victim to exhibit sociopathic behaviour i.e. reduced empathy, and remorse, and increased recklessness. These behaviors also tend to be far more pronounced in newly turned vampires, often resulting in them going on feverish feeding sprees that somewhat reminiscent of frat parties, but with more blood.
Another consequence of the turning is that the progeny becomes intensely devoted to their sire. as time goes on this relationship can either strengthen depending on whether it's nurtured or not as it is not a purely supernatural bond (the sire can issue unbreakable commands if they so choose, but the feelings of devotion are not supernaturally reinforced).

The problem: I'm basically looking for methods -be they game mechanics, DMing techniques, etc- of encouraging my players to roleplay these psychological changes without it feeling like I'm trying to play their characters for them. So far the only ideas I have are to have will saves to stop feeding/to avoid attacking and feeding on people under certain circumstances (when very angry, or when blood is shed for example), and to simply let them know the changes their characters have undergone and some of the ways this could potentially influence their decisions (I recognize that I'll have to do this regardless of what mechanics are in place).

[Troacctid]

Restore hit points every time you perform a violent act. They'll attack bystanders and smash objects between every combat to top up their health.

[frogglesmash]

Restore hit points every time you perform a violent act. They'll attack bystanders and smash objects between every combat to top up their health.

This would actually work really if it weren't for the fact that vampires have fast healing. Though d20 modern uses action points, so if I put a cap on those and have reckless behaviour grant action points it would probably have a similar effect.

[Extra Anchovies]

This would actually work really if it weren't for the fact that vampires have fast healing. Though d20 modern uses action points, so if I put a cap on those and have reckless behaviour grant action points it would probably have a similar effect.

Well, then the solution is to change the fast healing. Maybe for each hit point restored by their fast healing, one point is added to a running total (let's call it the bloodlust pool), and their fast healing stops working when [current HP] + [bloodlust pool] ≥ [maximum HP]. Whenever they commit a violent act, their fast healing starts working again for one round and the amount healed that round is subtracted from the bloodlust pool, so they can keep their fast healing running constantly by committing a violent act every other round. Without the violent-act exception, this would prevent fast healing from restoring more than half of the damage they take, so after a few combats your players will be itching to torture a hobo in a back alley or smash up a grocery store.

[Deophaun]

Change how you describe the setting and characters. If they're supposed to feel less remorse, cast the innocent bartender they just killed as an utter jerk. If they're supposed to grow attached to their sire, give them a penalty to Sense Motive checks against him. Invent "clues" that make them think their sire is secretely helping them. Basically, you control reality. Warp it.

[frogglesmash]

Well, then the solution is to change the fast healing. Maybe for each hit point restored by their fast healing, one point is added to a running total (let's call it the bloodlust pool), and their fast healing stops working when [current HP] + [bloodlust pool] ≥ [maximum HP]. Whenever they commit a violent act, their fast healing starts working again for one round and the amount healed that round is subtracted from the bloodlust pool, so they can keep their fast healing running constantly by committing a violent act every other round. Without the violent-act exception, this would prevent fast healing from restoring more than half of the damage they take, so after a few combats your players will be itching to torture a hobo in a back alley or smash up a grocery store.

The majority of damage players take is during combat, and since the majority of actions taken during combat are violent by necessity, the players will actively be draining their bloodlust pools during combat preventing their bloodlust pools from ever getting that full. If the players do take enough damage during combat for bloodlust to accumulate significantly the players will go out of their way to prolong/seek out conflict resulting in an uncontrollable domino effect of slaughter instead of a night of feeding a debauchery. I could be wrong about this, but that's how I predict it playing out.

I do like the idea of a bloodlust pool though, and I think it might pair well with some if linked to some sort of frenzy mechanic (a la frenzied berserker).