The Genetics of Problem Gambling

Can your genes make you a problem gambler?

People often blame genetics for a variety of bad things in their lives. But could losing the proverbial genetic lottery result in you becoming a problem gambler? This question has occupied researchers since the late 1990s. By the end of this article, you will understand the past 20+ years of scientific research and discover the answer to that very question. But first thing's first – the basics.

The terms problem gambling, gambling addiction, pathological gambling, and compulsive gambling refer to the same phenomenon called gambling disorder.

The American Psychiatric Association describes it in DSM-5 as an addictive behavioral disorder that involves repeated problematic gambling behavior that causes significant problems or distress.

Problem gambling affects all aspects of sufferers' lives, including their families, relationships, careers, physical and mental health, and of course, finances.

A person is considered a problem gambler when they manifest at least 4 of the 9 possible symptoms listed below (a.k.a. markers) over a period of twelve months.

1. needs to gamble with increasing amounts of money to achieve the desired excitement
2. restless or irritable when trying to cut down or stop gambling
3. repeated unsuccessful efforts to control, cut back on or stop gambling
4. experiences frequent thoughts of gambling
5. gambles when feeling distressed
6. chasing losses
7. lies to hide their gambling activity
8. jeopardies or loses a meaningful relationship, job, or education due to gambling
9. borrows money to resolve financial issues or to supply their gambling activity

Problem gambling was first recognized as a disorder in the late 1980s, thanks to Dr. Robert L. Custer, who spent years studying and describing the phenomenon. He initially defined it as an impulse control (or compulsive) disorder rather than an addiction. However, further research into the subject revealed a significant link between problem gambling and substance abuse, which lead to the change in classification.

Nowadays, problem gambling is understood, identified, and treated as an addictive behavioral disorder. Like any addiction, it's a complicated issue, impossible to assign a single cause, manifestation, or treatment.

The Role of Genetics in Problem Gambling

Conspicuous by its absence in this addiction model is genetics, which isn't necessarily the same as biological factors. Biology describes all natural processes which occur within our bodies, while genetics invariably involve heredity. Meaning, if problem gambling is genetic, it can be passed on from parent to child. Fascinated by the proposition, several studies were published independently of each other to try and confirm or disprove the possibility.

They tried to achieve this via several different genetic research methods:

1. Family studies
2. Twin studies
3. Neurobiological studies
4. Molecular genetic studies

1. Family studies

In terms of complexity, family studies are the simplest of all research methods described in this article. However, due to their comparable simplicity, they don't always produce the most reliable results. Family members don't only share their genes but are often subject to the same environmental and cultural factors. Therefore, familial transmission doesn't necessarily equate to genetic heredity.

There are two possible approaches to family studies:

• family-history method – a series of interviews with a sufferer of the illness in question, inquiring about the disorder's perceived presence in their relatives
• family-study method – a series of interviews with the sufferer and their relatives, studying the disorder's presence in their family

Several studies utilizing these methods were carried out over the years. One such study found that subjects who perceived their parents as problem gamblers were 3-times more likely to score as probable problem gamblers themselves. Ones whose perceived familial problem gambling history stretched to their grandparents were 12x more likely to score high on the problem gambling probability index.

A study of 817 high school students, out of which 4,7% were pathological gamblers, mentioned that the literature clearly established that parental gambling is a good predictor of adolescent gambling.

Taking a look at adults, a study of 95 pathological gamblers found that 11% of their first-degree relatives were definite or probable pathological gamblers themselves, whereas this percentage was only 1% in the control group. Like the studies above, these results suggest a strong link between problematic gambling habits of first-degree relatives.

2. Twin studies

This method compares monozygotic (born from one egg) and dizygotic (born from two eggs) twins. The logic behind it lies in the fact that monozygotic twins share 100% of their DNA, while dizygotic only 50%. Therefore, monozygotic twins should have higher odds of both being problem gamblers than their dizygotic counterparts.

The first study of this kind examined 3359 male twin pairs from the Vietnam Era Twin Registry. It claimed that heritability could account for 35% – 55% of the probability for problem gambling symptoms. So, for example, the marker "gambled more than intended" could potentially be explained by 55% heritability and 45% environmental factors.

Significantly higher chances of problem gambling were present in both monozygotic and dizygotic twins with clinical or sub-clinical level problem gambling parents. Furthermore, clinical and sub-clinical problem gambling behavior showed comorbidity (joint manifestation of multiple disorders or illnesses) with substance abuse, antisocial behavior, and mood disorders.

3. Neurobiological studies

This method investigates problem gamblers' brain chemistry and functions. As can be demonstrated via CTR scans, addicts' brains function differently than those of healthy individuals. And since a person's genetics can severely affect their brain chemistry and function, researchers saw fit to pursue this topic further.

They discovered that there are 3 chemicals and 3 parts of the brain, which play a significant role in problem gambling.

Chemicals with a significant role in problem gambling:

1. Serotonin is in charge of controlling emotions and encourages motivated behaviors (eating, drinking, sleeping, etc.). Disruptions in serotonin flow lead to moodiness and prioritization of non-essential activities over essential ones.
2. Dopamine governs the brain's reward systems by evoking feelings of euphoria whenever we engage in desirable activities, such as the motivated behaviors mentioned above. However, it stimulates us equally when we give into addictive urges (gambling, drinking alcohol, using drugs) and causes withdrawal symptoms when they are not fulfilled.
3. Norepinephrine (noradrenaline) prepares and motivates the brain and body to action. It controls our fight-or-flight instinct, promotes alertness and arousal, and helps with remembering and recalling memories. It also has to do with restlessness and stress. Gamblers experience high norepinephrine levels when gambling, resulting in "the Zone" effect and creating more gambling memories.

Parts of the brain with a significant role in problem gambling:

1. Cerebral cortex influences thoughts, emotions, reasoning, memory, etc. Changes in this part of the brain lead to impaired decision making, compulsivity, and impulsive behavior.
2. Amygdala is associated with "recording" positive and negative memories and creating habits.
3. Hypothalamus manages stress levels, so its inhibition can lead to an inability to deal with everyday life, resulting in unhealthy coping mechanisms like gambling.

It's worth stressing that these chemicals and brain parts don't only concern gambling addiction but other addictions (substance abuse, compulsive shopping, etc.), social (antisocial disorder), and mood disorders (anxiety, depression, etc.) as well.

4. Molecular genetic studies

Molecular genetic studies are the logical next step after neurobiological studies. These methods dive deep into researching subjects' DNA and look for anomalies in the genome in the form of allele variations and polymorphisms. Researchers then attempt to establish whether or not the presence of any given abnormality can determine the presence of addiction or illness.

Although it could be considered the most scientific method mentioned here, it still has its fair share of potential issues. The sample size of subjects, sexual and ethnic diversity, and the human gene pool's unfathomable size result in a considerably high risk of "false positive" results. Despite that, if the investigated genes are well-chosen and there is a diverse sample of subjects, this is one of the most useful study designs with the ability to detect moderate to small genetic changes with good statistical certainty.

Molecular genetic research has so far concentrated on the allele variations and polymorphisms present in genes associated with dopamine, serotonin, and norepinephrine. Additional research has been dedicated to investigating the role chromosomes play in the addiction.

Dopamine is of particular interest due to its involvement in the brain's reward system, as the reward system deficiency syndrome has a strong connection to many addictive behavioral disorders. Because of this association, dopamine receptor genes (DRD1, DRD2, DRD3, DRD4) were closely examined throughout the studies. Over the course of these studies, DRD2 and DRD1 were repeatedly connected to problem gambling, as was DRD4 to a lesser extent. Curiously, the DRD4 association was linked to female problem gamblers specifically.

In terms of serotonin, the polymorphism of its 5-HTTLPR transporter gene was common in male problem gamblers. Similarly, an association between the enzyme MAO-A was also represented only in male problem gamblers.

Verdict

After reviewing the body of works produced on this topic, we're ready to answer our initial question. However, it bears acknowledging that depending on the phrasing of the question, the answer may change and require clarification.

Can your genes cause you to become a problem gambler?

Yes, to a certain extent. However, cultural and social environments also play a significant role. So, depending on their circumstances, a potentially genetic problem gambler doesn't have to develop the disorder, while even a non-genetically predisposed individual can become a problem gambler.

Can problem gambling be inherited?

Yes. Certain DNA variations raise your chances of developing the disorder. As discussed in family and molecular genetic studies, these can be passed on from one generation to another.

Is there such a thing as a "problem gambling gene"?

Most likely not. PG's comorbidity with other addictions and disorders, such as alcoholism, drug use, depression, anxiety, and compulsive shopping, was repeatedly observed throughout the studies. So, while hereditary genes may make you more susceptible to these pitfalls, it is unlikely that there would be one for problem gambling specifically.

If problem gambling is genetic and biological, is it even possible to overcome it?

Yes, it certainly is. Despite all that was said in this article, problem gambling's nature doesn't make it impossible to beat. While battling any addiction is very difficult, rehabilitation is always possible through proper treatment. If you suspect you may be a problem gambler or know someone else who might be struggling with this addiction, we implore you to read up on the issue and seek help as soon as possible.