Researchers Find Hereditary Link in Pathological Gambling
When the topic of addiction disorders arises, substance and alcohol abuse are always at the forefront of the discussion while other addiction disorders get pushed to the side under skepticism. While there is clearly plenty of work to do be done to progress the biological mechanisms that contribute to addiction-related disorders like pathological gambling, a new study provides a step forward.
The study from the University of Iowa confirms that pathological gambling is hereditary and first-degree relatives of pathological gamblers are eight times more likely to develop this problem in their lifetime compared to relatives of those without pathological gambling.
“Our work clearly shows that pathological gambling runs in families at a rate higher than for many other behavioral and psychiatric disorders,” says Donald W. Black, psychiatry professor at the UI. “I think clinicians and health care providers should be alerted to the fact that if they see a person with pathological gambling, that person is highly likely to have a close relative with similar or the same problem. That is a teaching moment and they should probably encourage the patient to let their relatives know that help is available.”
Pathological gambling is defined as a gambling problem serious enough to become a clinical issue and is a major public health concern estimated to affect between 0.5 and 1.5 percent of American adults at some point in their lives.
The UI study is the largest of its kind to date, evaluating 95 pathological gamblers and 91 control participants, matched for age, sex, and level of education. The study also included 1,075 first-degree adult relatives of the study participants. Using interviews and proxy interview material, the team determined a gambling diagnosis for every individual in the study.
They found that 11 percent of relatives to pathological gamblers has gambling problems themselves, compared to 1 percent of the control relatives.
“People have always thought pathological gambling ran in families—anecdotal evidence certainly suggested it. But when you finally do a study like this, which is the largest of its kind, and come up with figures like this, it is quite striking,” says Black, who was lead author of the study published in the March issue of the Journal of Clinical Psychiatry.
The team then expanded their analysis to focus on problem gambling, which includes a larger group than those with the more narrowly defined pathological gambling. Their findings showed 16 percent of relatives of the pathological gamblers were problem gamblers, compared to 3 percent of relatives of control participants.
Lastly, the researchers examined the relationships between pathological gambling and rates of other psychiatric and behavioral disorders among study participants and found that relatives of pathological gamblers had higher rates of major depression, bipolar disorder, social anxiety, disorder, substance use disorders, post-traumatic stress disorder (PTSD), and antisocial personality disorder.
The researchers said antisocial personality disorder, social anxiety disorder, and PTSD were more frequent in the relatives of pathological gamblers independent of whether the relative also had pathological gambling, which “suggests that pathological gambling may share an underlying genetic predisposition with those disorders,” said Black.
It was previously believed that antisocial personality disorder may be biologically related to pathological gambling, however the connection with social anxiety and PTSD was a surprise to the researchers. Black says, “no one has ever published that and it’s hard to know what to make of it yet.”
The study also confirmed that mood disorders like major depression and bipolar disorder, as well as substance abuse, are common in pathological gamblers, however this is most likely not due to a shared biological factor.
“I think our findings should give impetus to neuroscientists who conduct molecular genetic studies to really pursue this,” Black says. “Maybe this situation provides a better chance of finding genes that are linked to the gambling disorder, and maybe that would pave the way for improving our understanding of the genetic transmission in general for psychiatric disorders, particularly in the realm of addiction.”