Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Thread Tools Display Modes
Old 04-03-2020, 08:44 AM   #1
Join Date: Oct 2010
Location: Cambridge, UK
Default [Basic] Disadvantage of the Week: Split Personality

Split Personality [-15] is a mundane mental disadvantage with a self-control roll, a fairly cinematic version of the real condition of ďdissociative identity disorder.Ē You have two (or more) distinct personalities, with different mental traits, who interpret their memories differently, and may use separate names. This disadvantage first appeared at GURPS 1e, although its mechanics have changed significantly, and older-edition Split Personalities arenít always exactly convertible to 4e.

To build these personalities, create a ďpackageĒ of mental disadvantages and quirks, and at the GMís option, variations in IQ, Per, Will and mental advantages. Your different personalities have different packages; only one is available at a time, and you only have to pay for one package. This is because you donít have any control over which personality you use: in a stressful situation, you need to make a self-control roll, or change to a different personality. This canít happen more than once per game hour, and if there are several possibilities, the GM gets to select a personality, or roll randomly.

Their total cost of each package must be the same, and the GM gets to enforce limits on disadvantages, on the number of quirks and/or perks you have at a time, and any other character generation rules they feel are relevant. Everything that isnít in a package, including physical traits and skills, is the same for all the personalities, although they are at liberty to not use skills, and pretend their other traits are lower (or higher, with Delusions, Overconfidence, etc.) than they really are. They can also have abilities that are only accessible to one personality: thereís a specific Accessibility value of -40% for that case.

Note that the number of personalities you have doesnít affect the cost. This leaves you free to create new personalities in play if the GM will let you; Iíd restrict it to after traumatic events, such as serious injuries and failed fright checks. All of your personalities are a bit shallow and unnatural, which gives you -1 to all reaction rolls. Anyone who witnesses you changing personality is likely to feel youíre seriously mentally ill, and react at -3 thereafter.

Split Personality is a plausible Secret Disadvantage, and an Evil Twin is readily mistaken for it. Personality Change is a Basic Set quirk-level version. Characters who have Shapeshifting with the Uncontrollable limitation may well have a linked Split Personality as well. Unethical Bio-Tech can cause it, and High-Tech psychiatric medication can suppress it, although itís always grounds for refusing gun licenses according to Pulp Guns. Reich-5ís unfortunate Mules suffer it in Infinite Worlds, which is probably worse than the Tsarevich Curse version from Worlds of Horror. Power-Ups 2 makes Split Personality a valid Controllable Disadvantage perk, and Power-Ups 6 has the interesting Residual Personality quirk for shape-changers.

A Psi-Tech Mind-Transfer Machine can fail this way, and itís a possible result of Psionic Powers crippling, or Steampunk Shocking Revelations. Some Supers characters have a Split Personality for their civilian identity, but a formal diagnosis forbids a Concealed Carry Permit most places, in the realism of Tactical Shooting. Thaumatology allows this disadvantage as a consequence of spiritual possession, and Ultra-Tech does the same for personality downloading.

A full case of Split Personality is character-defining, and fits much better into some genres, such as horror or illuminated games, than action-adventure. The only case Iíve seen in play was actually in Champions, but had similar mechanics: a descendent of Aramis, one of the Three Musketeers, was sometimes possessed by his spirit. This was made more complicated by the descendent being female, and Aramisí lack of interest in learning about the modern world. Eventually, the two personalities merged.

Has this disadvantage entertained in your games?
johndallman is offline   Reply With Quote
Old 04-05-2020, 12:38 PM   #2
Join Date: Apr 2005
Default Re: [Basic] Disadvantage of the Week: Split Personality

As written, it's a staple of Horror and Supers campaigns and works just fine.

To make it anything close to realistic requires lots of work. Realistic DID might actually be the most severe form of PTSD. In that case, traits such as Amnesia, Berserk, Compulsive Behavior, Delusions, Flashbacks, Odious Personal Habit, Phantom Voices, and/or Phobias might model certain aspects of DID better than Split Personality.

There's also the question of which personality manifests after a personality change. Realistically, DID "personas" emerge to help a victim of severe trauma survive. If the player can choose which personality emerges after a personality shift, it should be at least a -30% limitation.
Pursuivant is offline   Reply With Quote
Old 04-06-2020, 05:53 PM   #3
RogerBW's Avatar
Join Date: Sep 2008
Location: near London, UK
Default Re: [Basic] Disadvantage of the Week: Split Personality

I tend to feel that if anyone's in this state the narrative should really be about them Ė which in turn would mean that they're not just one PC in a party.
RogerBW is offline   Reply With Quote
Old 04-06-2020, 10:54 PM   #4
Join Date: Apr 2005
Default Re: [Basic] Disadvantage of the Week: Split Personality

Originally Posted by RogerBW View Post
I tend to feel that if anyone's in this state the narrative should really be about them Ė which in turn would mean that they're not just one PC in a party.
That's one way to play it. In a sillier or cinematic game, the other members of the party can get in on the game. Either, "OK, who are we actually talking to, and can you help us?" or "What do we have to do to get Adventurer-Clyde back in charge, instead of Nature-Spirit-Clyde?"
Pursuivant is offline   Reply With Quote
Old 04-07-2020, 01:13 AM   #5
Ultraviolet's Avatar
Join Date: Apr 2008
Location: Ňrhus, Denmark
Default Re: [Basic] Disadvantage of the Week: Split Personality

I played a character with this once, and it is the only time I've seen the Disadvantage in play in my 30 years or so of GURPS.

It was back in 3rd ed in the mid 90s, we playes a lot of Cyberpunk campaigns. Back then the Disadvantage said you made two character sheets, which may differ in IQ and mental traits, and the point value of the two had to even out to the campaign budget. So in effect you could get one weak and one strong personality.
IIRC I built the character on the manic-depressive concept, with one one personality quiet, careful, moody and the other loud and boisterious. I don't think that game lasted very long, I can't really remember it having much of an impact.
Playing GURPS since '90, is now fluent in 4th ed as well.
Ultraviolet is offline   Reply With Quote
Old 04-07-2020, 11:45 AM   #6
Default Re: [Basic] Disadvantage of the Week: Split Personality

I've used it on a few NPCs... but then I also made the 'personality swaps' controlled by the narrative. Which 'personality' did I require in charge at any given time.

One was a blandish "good" NPC vs "not-so-good" NPC switching, in other words the NPC didn't swap full personalities, just 'natures', from being very outgoing and helpful, to very (inappropriately) friendly, to withdrawn/unstable, to taciturn and vengeful.

The other was mind-controlled/rewritten and had a "helpful to the PCs personality and a "malevolent to the PCs" personality which took over at every chance it could and did things to hamper the PCs. Eventually the "good" personality fessed up, thinking it was suffering from a possession... well, the PCs cured the NPC of the split personality at which point it was the original "doesn't like the PCs" personality in charge and the sabotage continued...
  Reply With Quote

disadvantage of the week, split personality

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump

All times are GMT -6. The time now is 07:44 PM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2022, vBulletin Solutions, Inc.