Abbreviations:

Xan = Xanax
rehab = Rehabilitation at Switzerland
AP = Addiction Points
BSR = Battle stat Reduction (side effect from drugs)
JP = Job Point (gained while in Job)

AP values

1 Xan = 35 AP (without toleration, a faction perk)
With Toleration perk @ 50% addiction Reduction: 1 Xan = 18 AP

1 rehab = 90 AP reduction (at first rehab) ---> declines up to 1 AP reduction (with number of rehabs done, not with number of drugs taken)

So refrain strictly from clicking multiple times on rehab when in Swiss.

Natural addiction decay = 21 AP/day

So, when we have max 'toleration', we can take 8 xan per week without ever needing rehab.

Company specials for drug addiction reduction (Flower shop/Cruise line/Night club) =>

 1 JP = 1 AP
(Can save upto 250k/JP @ max rehab)

Cost of Rehab

it starts at
1 Xan = 100k

35 AP = 100k => 1 AP = 2857

Cost goes up with number of rehabs done (you can find the 'number of rehabs done' in personal statistics tab on your profile page)

Equation
[2857 + (12.85 x no of rehabs done)] per Addiction point

Ex:

A person with 12 rehabs done --> next rehab costs at 3011/AP
Which clears 250000/3011 = ~83 AP (~2.5 Xan)

At 2000th rehab => 1 rehab cures only ~ 8 AP => 1 xan needs almost 4 rehabs.

The max tolerance for rehab is 1 AP = 1 rehab (250,000$) => 1 Xan rehab = 8.7 mil

Education kick

You will be kicked out from any ongoing education course when you have...
-7% BSR or 250 AP (~ -30 to -32 Company efficiency reduction)

P.S: Job at Night Club can have a Passive at 10* which allows you to rake up addiction without getting kicked out of education (but you will be kicked out of the company soon. So it is mainly useful for the Director. Director's addiction has no role in company efficiency.)

Addiction & Company

If you have a job at player company, you need to worry about your addiction status as it reduces your work efficiency which can make your director unhappy.

So when to go for a rehab while working?

You have to go to a rehab too frequently if your efficiency is just around 100%, because there would be no buffer to take your addiction points.

The math...

8 AP = -1 Point of Efficiency (This is how you can tell your AP exactly @ 1800 TCT)
Now its up to you when to rehab.

Ex: If you have an addiction brain icon showing (-4% BSR) = 200 AP = -25 Efficiency reduction in company.

Addiction Gain on Xanax Over Dose: (need further conformation)

It is said to be [1-3x] => upto ~100 AP per OD

Best suggestions:

1. Always utilize natural decay. (No full addiction rehab at swiss)
2. Always try to get your rehab done just before 1800 TCT, which can improve your job efficiency significantly.

This is the hard work of number of players who did wonderful math to find these out. I have just compiled it here for easy reference.

Thank You.