PARIS – Genetic studies are finally making an impact in addiction medicine, as evidenced by the inclusion of three genomewide association studies in one expert’s list of the year’s top 10 developments in the field.
The three genetic studies that made their way onto this admittedly personal top 10 list of advances in addiction medicine include the surprising results of the first-ever genomewide association study of pathological gambling, a methylomic profiling study implicating a gene that regulates low-density lipoprotein cholesterol in the pathogenesis of alcohol use disorder, and a study that identified a specific microRNA as a regulator of motivation for cocaine, Philip Gorwood, MD, PhD, said at the annual congress of the European College of Neuropsychopharmacology.
Bruce Jancin/Frontline Medical News
Dr. Philip Gorwood
“This was an extremely important development, because it means pathologic gambling is a behavioral addiction,” said Dr. Gorwood, also head of the Clinic for Mental Illness and the Brain at Sainte-Anne Central Hospital in Paris. “This makes a difference to research because it means what we observe in the brain is really due to the patient’s behavior, to his or her choice to gamble, and not because they’re taking alcohol or cocaine or nicotine.”
His list of the year’s top 10 studies in addiction medicine follows:
Deep TMS in AUD
There is a general sense within the field of addiction medicine that transcranial magnetic stimulation (TMS) might have efficacy in some addictive disorders, but it has been hard to make a convincing case for the therapy when the mechanism is unknown.
Italian investigators have brought clarity in a study published in European Psychopharmacology (2017 May;27[5]:450-61) in which they randomized 11 patients with alcohol use disorder (AUD) to 4 weeks of real or sham deep TMS sessions, coupled with baseline and follow-up single-photon emission computed tomography (SPECT) imaging of dopamine transporter availability in the striatum of the dorsolateral prefrontal cortex. After 4 weeks, the group receiving real TMS showed a clinically important reduction in alcohol intake accompanied by a significant decrease in their elevated strial dopamine transporter availability, while sham-treated controls were unchanged. “This was a small study, but I loved the way the investigators merged a pilot clinical study with a biologic mechanism study,” Dr. Gorwood commented.
Coffee drinking and mortality
Investigators for a prospective cohort study of 521,330 people enrolled in the 10-country European Prospective Investigation into Cancer and Nutrition concluded that, during a mean 16.4 years of follow-up, participants in the top quartile of coffee consumption had a significantly lower risk of all-cause mortality, compared with those who did not drink coffee: a 12% reduction in men and a 7% reduction in women.
Moreover, the risk of mortality tied to digestive disease was reduced by 59% in high– versus non–coffee-consuming men and by 40% in women in this report from the International Agency for Research on Cancer, in Lyon, France . High–coffee-consuming women, but not men, also had a significant 22% reduction in circulatory disease mortality and a 30% lower risk of cerebrovascular disease mortality, compared with those who did not drink coffee.
Of particular interest to psychiatrists, the investigators also examined suicide risk. In a multivariate analysis, men in the third and fourth quartiles of coffee consumption were at 36% and 29% lower risk of death by suicide than those who did not drink coffee. Suicide in women occurred less frequently and was not related to coffee intake.
These various associations did not vary by country, even though coffee preparation methods vary considerably across Europe. And when the investigators excluded participants who died within 8 years of baseline, the results were unchanged, a finding that makes bias tied to reverse causality less likely as explanation for the results, the findings published in the Annals of Internal Medicine (2017 Aug 15;167[4]:236-47) showed.
“As addiction specialists, our patients often complain that we are forbidding everything. We are the bad guys: Don’t drink too much, don’t eat too much, and so on. The key finding in this European study is that you will not die of coffee drinking, even if you are having 8 cups a day. Yes, we know that coffee has a psychotropic effect, we know that you have a tendency to repeat its consumption, but it is really quite readily distinguishable from other addictive substances,” the psychiatrist said.