A new study has revealed that the risk of substance abuse and other addictions is high among those who have a history of binge eating.
In the short term, this finding by researchers from Penn State College of Medicine, may shed light on the factors that promote substance abuse, addiction, and relapse. In the long term, may help clinicians treat individuals suffering from this devastating disease.
"Drug addiction persists as a major problem in the United States," Patricia Sue Grigson, said.
"Likewise, excessive food intake, like binge eating, has become problematic. Substance-abuse and binge eating are both characterized by a loss of control over consumption.
"Given the common characteristics of these two types of disorders, it is not surprising that the co-occurrence of eating disorders and substance abuse disorders is high. It is unknown, however, whether loss of control in one disorder predisposes an individual to loss of control in another," Grigson said.
Grigson and her colleagues found a link between bingeing on fat and the development of cocaine-seeking and -taking behaviours in rats, suggesting that conditions promoting excessive behaviour toward one substance can increase the probability of excessive behaviour toward another.
The researchers used rats to test whether a history of binge eating on fat would augment addiction-like behaviour toward cocaine by giving four groups of rats four different diets: normal rat chow; continuous ad lib access to an optional source of dietary fat; one hour of access to optional dietary fat daily; and one hour of access to dietary fat on Mondays, Wednesdays, and Fridays.
All four groups also had unrestricted access to nutritionally complete chow and water. The researchers then assessed the cocaine-seeking and -taking behaviours.
"Fat bingeing behaviours developed in the rats with access to dietary fat on Mondays, Wednesdays, and Fridays-the group with the most restricted access to the optional fat," Grigson said.
This group tended to take more cocaine late in training, continued to try to get cocaine when signalled it was not available, and worked harder for cocaine as work requirements increased.
"While the underlying mechanisms are not known, one point is clear from behavioural data: A history of bingeing on fat changed the brain, physiology, or both in a manner that made these rats more likely to seek and take a drug when tested more than a month later.
"We must identify these predisposing neurophysiological changes," Grigson said.
While the consumption of fat in and of itself did not increase the likelihood of subsequent addiction-like behaviour for cocaine, the irregular binge-type manner in which the fat was eaten proved critical.
Rats that had continuous access to fat consumed more fat than any other group, but were three times less likely to exhibit addiction-like behaviour for cocaine than the group with access only on Mondays, Wednesdays and Fridays.
"Indeed, while about 20 percent of those rats and humans exposed to cocaine will develop addiction-like behaviour for the drug under normal circumstances, in our study, the probability of addiction to cocaine increased to approximately 50 (percent) for subjects with a history of having binged on fat," Grigson added.
The study has been published in Behavioral Neuroscience.