Was going to respond to your question but I extrapolated it too much and ended up making another thread. Point being; you need to apply your suggestion to something gameplay wise.

I like the idea of players getting addictions because they take too many drugs (morphine, painkillers, etc) or alchol (because maybe there is nothing else to drink or they don't have painkillers?). Perhaps their character starts suffering from Schizophrenia which gives away your position (character mumbling to himself) and/or causes delusions (impaired vision/seeing zombies). Given how fond of PZ Rocket is I don't think this is too far wrong. Take it further and you could add in addictions to food where your character becomes 'fat' and requires more food to survive the fatter you become until you run it off and eat healthy (wouldn't take long within the running simulator). Also the fatter you are the quicker you become exhausted and/or can carry less. Of course this would require the game to have unhealthy foods which is a little out of character, especially with Rocket's ideals of survival, living off the land and such. Its all a question of how far down the rabbit hole you want to go. This idea is sponsored by Project Zomboid. Sorry if this has been suggested (probably has) previously or discussed by Rocket. I posted this kinda by accident (was writing a reply and ended up just started a new thread).

It is so easy to dodge and kill zombies with fists, or at least knock them out and run away that I don't mind not having a weapon. It is also very easy to find weapons and avoid zombie encounters all together, so again I don't see a reason. Perhaps with more experience you too will find zombies aren't really a threat.