My understanding, Sitetest (and this is a question to you) is that one of the most straight forward reasons for legit annulments from the Church is if one person was under the influence of substance abuse at the time of marriage, alcoholic or otherwise.
The paperwork I recall reading stated that this was because it was impossible for someone to truly enter into the compacts professed to the other and the Church in that altered and dependent state.
Does that jive with your knowledge?
I don't know whether substance abuse at the time of the wedding is a particularly common ground, but lack of effective consent certainly is pretty common. Usually, though, lack of consent is attributed to extreme immaturity, or failure to understand the sacramental nature of marriage. But certainly, folks who are not sober, especially at the time of taking their actual vows, have an impaired ability to provide effective consent.
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