Poor self control gives a character a negative compulsion if they fail a composure (2) check.
Adrenal regulator (from WAR!) reduces the threashold of composure checks by 2.

Just putting out there to GMs that if a player has this combo then they're probably gaming the system, and should choose something else.

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Poor Self Control gets you between 5 and 15 points, and requires a Composure (2) check.

Adrenal Regulator costs 9,000 nuyen (so basically 2 points of of your equipment budget, and 1/25th of your total allowable equipment budget,) an 0.1 Essence.

Does the player come out ahead? Slightly. However, even if the threshold is 0, they still have to roll, a roll on which they may still glitch, or critically glitch. If they glitch, I'd say the threshold went up by 1 for half of the die coming up 1s, and another +1 threshold for every additional 1.

I believe in the German Errata the regulator increases the dice pool for Composure tests by 2. Because that's what the author intended, but he didn't know SR4 dice mechanics.

How the christ did some jackass get to write mechanics without knowing the dice rolling system?

This was only an asumption of mine, of course. But really, isn't that how Catalyst works these days?

Or, is it entirely possible that he felt that an adrenaline regulator should reduce the threshold of Composure tests by 2?

To the best of my knowledge you can take multiple poor self control negative qualities, potentially filling your entire 35 bp with them.
also, add the MPC bridge (another 3 BP of wealth and 0.1 essence) to ignore normal glitches and downgrade critical glitches to normal glitches.

Eh. I see that combination as no worse than taking the BiPolar quality, then automatically increasing your lifestyle costs by 500/month (for the medication).

That combo is a perfect justification why the trait does usually not affect the story. In specific situations I as the GM would ask for harder composure checks.

I am reminded of one of the rules in GURPS regarding disadvantages.

If a Disadvantage has no effect then it provides no points. Or something like that...

If the GM allows a player to take it then more power to them, just don't expect it to fly at other tables.

Or just annoy the players by having them roll the dice for it very often. At some point, they'll hopefully become annoyed enough with it to buy off the disadvantages or ask to get them changed.

I would never have them roll dice for it... At threshold 0 all they need to do to get a critical success is roll 4 hits... I would not give edge back for a flaw that is not a flaw.

Emphasis mine.

I see no problem with a negative quality giving a threshold 0 composure test.

mainly because another negative quality already exists that allows it out of the box. That is the Prejudiced quality at the Biased level. So the standard is already set.

As shadowdragon pointed out, you still have to roll.

Meh... True enough...
We house rulled that you need to get at least half of your dice pool as hits and have a minimum of 4 hits over the threshold to get an edge back...

We have so many house rules at our table to the point that I forget the actual rules sometimes.

Close enough. I don't recall the exact text, but the effect is the same. Disadvantages cost 0 if it has no impact on the character.
(Likewise positive advantages, of which there are many--gender qualifies as such!)

Sure and fine, but then, the player HAS felt an effect: they've spend essence and starting nuyen on an implant to counteract (most of) the bad effects.

Yes... HAS...
It is the same as starting with the In Debt quality and paying it off after one run. It no longer has an effect and therefor is no longer worth points and must be bought off.

I am a player more than a GM and even as a player I see it as abusive... If other players and GM's want to go that route that is fine I will not, as a player or as a GM.

Actually, it does have an ongoing effect, albeit a small one: they are still down 0.1 essence, and that 0.1 essence is still "occupied" (meaning, "is not a hole that can be filled with other implants").

Frankly, it's the same as being Paraplegic ... then buying a wheelchair (or better, a Transys Steed drone) and modifying it to minimise or negate any mobility issues. (One buildI have partway done did just that - the Steed has Walker mode, and Gecko Tips, so technically the character is (when properly strapped in) more mobile than before: he can literally walk straight up a wall.