Has anyone written a stat-block for the effects of alcohol and/or synthahol? I couldn't find any in the books.

My idea would be to reduce Reaction and grant High Pain Tolerance. Other stats might be affected too, but I'd like to keep it simple. I'm thinking the addiction threshold would be 1 on the 1-3 scale, given that alcohol is not necessarily a "powerful" drug for runners to abuse (like Kamikaze or Nitro).

Also, what exactly is synathol? Is it like Star Trek synthehol, which tastes the same but lacks the buzz, or is it just cheap, unhealthy booze?

I may well be wrong here, but I think synthahol is just cheap, synthetic alcohol.

I'd say Synthahol is cheap, unhealthy booze that's slightly reminiscent to Victory Gin from 1984.
Addiction threshold should be 3 (for sedatives), but i wouldn't call for Addiction tests too frequently.
SR4 drug rules are entirely dependent on GM common sense to work anyway.

Giving exact stats is difficult, as effects vary with dose, whereas the rules do not differentiate in that matter.
So you'll either end up with a very abstract, possibly implausible representation of the effects or with something that is not in line with existing substances.
But your suggestion seems a good approximation.

Thanks for the replies.

Let me make sure I understand how a moderate addiction works by RAW. Here's my notes (assuming alcohol is threshold 1 and primarily a physical addiction):

Alcohol Addiction (Moderate):
Craving 1/day. Suffers -4 dice to resist cravings.

Roll Body + Willpower (1) for Addiction Tests after repeated use, a particularly brutal bender, or exposure to strong concentrations in a short time. Failure leads to a Severe addiction.

Roll Body + Willpower - 4 (1) to resist daily cravings. Failure leads to withdrawal symptoms (dice pool penalties, etc.) until I get my fix.

I would go with -1 Agility, -1 Reaction and -1 Intuition (for perceptions purposes), High Pain Tolerance 2 and the possibility of 1 in 6 of becoming an annoying druken bastard no ones likes to hang out with

If you are going to do dice-pool modifiers, I would add +1 to Con and Etiquette while buzzed, which changes to –1 for the whole Influence group when drunk. (Not just Charisma because of Negotiation etc.)