Professor Drake: Alcoholism

An empirical discussion of alcoholism's risk factors, biological vs. environmental, and PTSD comorbidity

One of my favorite units from my psychopharmacology class was the alcohol unit. Since I had to pay $70,000 a year to learn this information, I feel it is my leftist praxis duty to disseminate this knowledge for free, hence the creation of the Professor Drake series where I will share some of the most interesting things I learned in college. I know that this is probably not what most of you subscribed to see - I know you guys like me for my emotional writing, personal sharing, life perspectives, vulnerability, etc. I know that most normal people would not choose to read informational shit for fun that feels like biology class homework. But I also started my Substack to create content that more reflected me as a person and my mind and my inner world, and I am an autistic nerd. I love this shit. I enjoy learning about it and talking about it. So I want to acknowledge that Professor Drake content may not be everyone’s cup of tea, and that’s okay. I will be posting something for everyone.

Now, I am a woman of science, and I always strive to adhere to the basic principles of academic writing and scientific research review, which is to cite your sources. Unfortunately, I’m drawing from 1) my memory of what I learned in class and 2) my notes from class, neither of which include citations. So I’m sorry, this will be sourceless, but the sources could probably easily be found with a search.

What I found most interesting was learning about the predictors and factors related to who become an alcoholic, and in what ways.

I. First let’s look at the two alcoholic subtypes:

Type 1: These are people who start to drink problematically later in life. Their motivation for using alcohol is to cope with emotional distress or life circumstances, and they feel guilty about their drinking - they are aware that it’s bad and are ashamed. Most women are type 1.

Type 2: These people begin drinking early in life, most likely due to premature environmental/social exposure. They typically feel no guilt about drinking, or choose not to see it as problematic. They are thrill-seeking and usually antisocial, and typically have very low levels of serotonin. These types tend to have a high genetic vulnerability. Type 2 alcoholics are almost always male.

II. Causes/predictors of alcoholism: nature vs. nurture

I think it’s pretty widely known that substance abuse disorders, especially alcoholism, have a long-proven biological basis in genetics, at least in terms of risk prediction. Close relatives of an alcoholic have a 3 to 7 times higher risk than the general population for alcoholism. In monozygotic (identical) twins, there’s usually around a 40-50% concordance rate in alcoholism (meaning if one twin has alcoholism, there’s a 50% chance that the other twin will also develop alcoholism at some point). Interestingly, this varies by gender - between male monozygotic twins, the concordance rate is 50%, but only 30% between female twins. I will spare you from going too into detail about the more nuanced biological factors, but in case there’s anyone with remotely interested in that, I will briefly list them in a footnote¹.

The nature vs. nurture question is prominent in psychology to determine the genesis of various disorders, and if you have majored or minored in psych, you know the importance of comparing twin studies (like above) and adoption studies to analyze this question. So, to contrast to the genetic links, adoption studies found that children who are adopted by alcoholics are more likely to be alcoholic, regardless of genetic predisposition from biological parents. Also strengthening the nurture side of the issue is the unsurprising data that exposure to early life stressors increases the risk for developing alcohol use disorder (duhh). This opens up another conversation of the relationship between alcoholism, life experiences, and trauma.

III. PTSD and Alcohol Use Disorder: comorbidity/dual diagnosis and risk factors

While early life stressors are risk factors predicting the development of PTSD and AUD alone, childhood adversity also predicts the comorbid development of these. Studying PTSD and AUD from a dual diagnosis standpoint proves really interesting. For example, adolescents who experienced personal violence were more likely to develop comorbid/dual diagnosis of PTSD and AUD than either one of them alone. In a similar vein, people with comorbid PTSD and AUD were more likely to have had adverse childhood experiences than those who had just one or the other.

Women are twice more likely to be diagnosed with PTSD in their life than men, but men are twice more likely to be diagnosed with Alcohol Use Disorder (hereon referred to as AUD). This complicates the ability to understand gender differences in likelihood to develop comorbid PTSD and AUD. What is observable is that differences in the type of trauma experienced create vastly different outcomes/predictors in terms of singular AUD, singular PTSD, or comorbid AUD and PTSD diagnoses. While sexual assault is a global risk factor for PTSD, the risk for developing AUD depends on the circumstances of the assault (meaning, not all assault is empirically just as likely to predict AUD development). For example, women who were assaulted while intoxicated were more likely to develop AUD than those who experienced assault sober.

IV. Beliefs and thought patterns as predictors for alcoholism and factors in disease longevity

It’s difficult to place one’s beliefs/thoughts about drinking in the nature or nurture category of explanation, but this factor is extremely interesting in terms of its prediction of different features of alcoholism such as onset and continuation.

Among sexual assault survivors who had PTSD (already a group highly predisposed to developing AUD), women who believed that drinking could reduce stress were vastly more likely to actually develop AUD than others. This seems kind of duhhh, but it’s important to understand how beliefs can shape empirical outcomes.

One especially potent belief/thought predictor in alcoholism is expectancies - meaning, do you expect to get pleasure from alcohol. Some studies have found that expectancies are an even better predictor of alcohol use disorder than demographic and background variables, adding nuance to the nature vs. nurture analysis. For example, expectancies of alcohol pleasure/enjoyability among 7th and 8th graders predicted their rates of alcohol use one year later more accurately than almost all other factors.

1. Higher aldehyde dehydrogenase activity (the enzymes that catalyze the oxidation of aldehydes), variation in CRF1 receptor gene shown to moderate stress-induced alcohol drinking, and D2 receptors are expressed lower in alcoholic patients (possibly links to overactive release of dopamine, leading to finding drinking more enjoyable than most people).