Hear's the strait dope, so to speak, fresh from 5E.
QUOTE ("SR5 @ p. 414)
Every time you use an addictive substance during (11 - Addiction Rating) weeks in a row, you need to make an Addiction Test. The clock on this keeps ticking even if you skip a week, but every week you go without indulging reduces the Addiction Threshold by 1 (it returns to normal when you use again). If the threshold hits 0, you’re off the hook until you use the substance again. This means that substances with high Addiction ratings (like kamikaze) could get you hooked in a single dose.
Now, this is
very confusingly worded. Let me see if I understand this properly.
You take a dose of Kamikaze, which has an Addiction Rating of 9 and an Addiction Threshold of 3. That sets your "Addiction Timer" to 11 - 9, which equals 2 back-to-back weeks, during which time you need to make an Addiction Test any time you take a dose of Kamikaze?
Except that doesn't make much sense, does it? Kamikaze is supposed to be highly addictive, so why is the time period you risk addiction only 2 weeks long? Meanwhile, drinking alcohol, which has only an Addiction Rating of 3, would mean that you make an Addiction Test every time you drink during an 8 week period? So that
can't be how this operates.
Okay, wait. I think I got it now. You risk Addiction after having spent X number of weeks, back to back, taking at least one dose of the drug per week? So if you take a dose of Kamikaze one week, and then another one a week later, you have to make an Addiction Test. Meanwhile you have to partake of alcohol for 8 weeks in a row before you run the risk of addiction and have to make a test to resist it?
So.. what's all the mumbo jumbo about the timer counting down? Lemme see... I think I've made sense of it. Let's say you have a drink. That sets you at an eight week timer. During that time, if you drink every week, you'll ultimately have to make an Addiction Test against a Threshold of 2 to avoid being addicted. If you drink the first week, but then don't drink the second week, the eventual Addiction Test threshold drops by 1. So if you spend two weeks during that eight week period not drinking, you drop the Threshold to 0, meaning you can't become Addicted until such time as you take more of the drug and start a new Addiction Timer.
However! If you start out with a drink in week one, then only take one week off of drinking, and then on week three hit the bottle again? The drop in Addiction Threshold you earned by not drinking in week two is eliminated - the threshold returned to it's full, original power when you partook again.
But now I don't understand the bit about getting hooked on Kamikaze in a single dose, though. Unless... okay... so if you take a dose of Kamikaze, even just one,
at the end of 2 weeks you have to make an Addiction Test? So you take one dose in the first week, and then in the second week you stay clean. However, that only reduces the Addiction Threshold from 3 to 2, so you still have to make an Addiction Test - which you can fail, thus becoming addicted from a single dose? Is that what they mean?
Okay, let me sum up where I currently stand in terms of understanding this...
Step 1: Take a drug.
Step 2: Set a Timer for 11 - Addiction Rating weeks, at the end of which you may need to make an Addiction Test.
Step 3: For every consucutive week spent clean before the test, reduce the Treshold for the Addiction Test by 1.
Step 4: If the Threshold hits 0 before the Timer is up, you no longer have to make an Addiction Test. Congratulations!
Step 5: If at any time you take more of the drug before the Threshold reaches 0, it returns to full.
Step 6: When the Timer goes off, make an Addiction Test at the modified Threshold.
Step 7: Either meet the modified Threshold and be clean, or fail your Addiction Test and gain the Addiction Negative Quality.
Except... this doesn't mesh well with the way the rule is worded!

Can a dev come explain explain this mess?
~Umi