“Any one of us could be an addict at any time. Addiction is not fundamentally a moral failing—it’s not a disease of weak-willed losers,” David J. Linden, professor of neuroscience at the Johns Hopkins School of Medicine in Baltimore, MD said.
As part of the Mind Science Foundation Distinguished Speaker Series for 2011, Linden spoke about how research is allowing us to gain a better understanding of how pleasure affects our brain. The lecture was held Sept. 19, at the Pearl Stable Auditorium, near downtown San Antonio.
In his lecture titled Feels So Good: Vice, Virtue, and the Brain’s Pleasure Circuits, Linden combined cutting-edge science with humorous stories to expose the cause of the behaviors that can lead to ecstasy but that can also become addictive.
According to Linden’s research, pleasurable experiences are registered in a section of the brain called the medial forebrain pleasure circuit. When pleasurable activities are experienced the release of dopamine allows for the sensation of pleasure. Dopamine is a neurotransmitter that helps control the reward and pleasure centers of the brain.
In his lecture, Linden asked the question, “Why should the brain have a pleasure circuit?” He went on to explain that “pleasure is central to learning, for we must find things like food, water and sex rewarding in order to survive and pass our genetic material to the next generation.”
Many things can control the amount of dopamine the brain will release. Some drugs, like heroine and marijuana, artificially activate levels while others, like Prozac, tranquilizers and LSD, short-circuit levels. If they activate the pleasure circuit then the drugs are addictive.
The dark side of pleasure is addiction and genetics plays an important role in who becomes an addict and who doesn’t. Linden explained, “There are variants in genes that turn down the function of dopamine signaling within the pleasure circuit.” People who have the gene variant do not experience pleasure with as much intensity as those who do not have the gene variant. For instance, one person at a bar might find pleasure with two drinks while another person would need to have six drinks to experience the same level of pleasure.
Even with the gene variant as a factor, only 30 percent of heroin users become addicts while 80 percent of cigarette users become addicts. Linden explained that addiction has to do with the dosing schedule. A heroin user will tend to use once a day compared to a cigarette user that might have as many as 20 or more cigarettes in a day. The smaller repetitive doses make it easier to become an addict.
Linden also spoke about sex addiction. According to Linden sex addiction is real and true sex addicts, as well as heroine addicts, no longer find pleasure in the experience. They continue with the experience just to get to sleep at night, wake up in the morning or to prevent anxiety attacks. Linden said that when addicts talk about getting their fix they tend to say that they’ve “got to get healthy.” Cravings become so great that the addiction wears the pleasure away. “Those who still like having sex are not real addicts,” Linden said.
The pleasure circuit can also be activated by the act of gambling. Studies show that even the anticipation of winning at the poker table can raise dopamine levels. Participants in the study were monitored as they played roulette. As the wheel spun, the dopamine level gradually increased. With a win there was an extra spike, with a loss there was a drop. “We are hard-wired to anticipate,” Linden said.
The lecture concluded with time for questions and answers, which included a lively discussion about the difference between video game addictions for men and women—combat-styled games for men, Tetris for women.