There is no info in the game about the actual effects of a drug withdrawal. These information were depicted in the past, but have been removed in the patch that changed and added description to the drugs itself (so like 2years ago I think).
Wake-up addiction/withdrawal:
https://steamuserimages-a.akamaihd.net/ugc/1841409905608326908/762432AC91E5FBA4F6B5A7AA0E4DF4FDF2F68CDF/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
https://steamuserimages-a.akamaihd.net/ugc/1841409905608329285/CFE8B9CF0FA1F3A8EF7189F009C9C41F91A72836/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
Alcohol addiction/withdrawal:
https://steamuserimages-a.akamaihd.net/ugc/1841409905608327278/024F6AFE57941622843029232BEDE5BAEB9E5F1E/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
https://steamuserimages-a.akamaihd.net/ugc/1841409905608329668/BCE8286857A5A08521DE1555C8C9953390056973/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
What has been added in the past is information about the chance and cost of an addiction, but almost all information you would like to know when you want to get rid of the addiction has been removed. The only thing that is known is the recovery time needed, yet that time is also only available on the drug itself and not the addiction, making the information hidden if you do not have the drug.
Random drug addiction info: https://steamuserimages-a.akamaihd.net/ugc/1841409905608330107/77D317069192A229788153E89F70C52FD0B138D7/
You can of course read all entries in the health tab to add up the effects of the addiction yourself (like reduced manipulation), but even that does not show everything (like rest fall rate changes). Since the addiction/withdrawal entries on the health tab used to show the effects of withdrawal, I would call this a "bug", since it was probably removed by accident. In addition to the health effects it could be cool to see at least some info from the drug's addiction paragraph on the additional info card of the withdrawal too.
Example of what wake up withdrawal does to the health (+other info): https://rimworldwiki.com/wiki/Wake-up#Withdrawal_Symptoms
Both DLCs, no mods used.
Thanks for the report. It may have been removed for some reason I'm not aware of, but either way I will bring up the absence of the actual game effects of withdrawal for each drug in the health tab.