 This is evidenced by the fact that he experiences physical withdrawal symptoms when he attempts to stop drinking.Jack also appears to be an opportunistic substance abuser, given that, in various episodes, he drinks Kenneth's cough syrup in lieu of alcohol, sniffs paint (and Jenna's breath) to alleviate his alcohol withdrawal symptoms, scoffs at the notion of sober air travel, takes mysterious purple pills offered to him by Dr. Spaceman, and is shown on the cover of a 1985 GE Quarterly Newsletter claiming that a wheelbarrow full of cocaine was just out of view.While trying to adjust to life as a housewife, Liz finally realises that Jack did not have everything figured out and was "just an alcoholic with a great voice."