Emotions are often implicit undertones to our communication interactions, and decoding them requires substantial social and cognitive abilities. A study of the ability of chronic male alcoholics to recognize the emotional component of irony in relation to their empathic abilities has found a clear deficit.
More specifically, the alcoholics demonstrated: a deficit of empathic functions; a specific impairment of the "social skills" component of empathy; a disturbed comprehension of irony; difficulties in recognizing the emotional dimension in communication; difficulties in identifying speakers' emotional states and intentions; and an overestimation of positive emotions and a misunderstanding of the negative connotation of ironic situations.
[Of course . . . hard to know which came first. It's entirely possible that their low levels of empathy and resulting relationship difficulties led to the chronic alcohol abuse to begin with.]