NCJ Number
172385
Date Published
1998
Length
5 pages
Annotation
This paper describes a study with rats that examined whether environment and stress or biological affinity are the primary factors in the use of opiates.
Abstract
In an effort to examine the impact of environment and stress on rats' use of opiates, the researchers put one group of rats in the "normal" housing for laboratory animals in psychopharmacology experiments, i.e., individual cages mounted on steel racks, constructed so that the animals could not see or touch each other. The environment for the second group of rats was the most natural habitat that could be contrived in the laboratory, so it was named "Rat Park." Rat Park is open and spacious, with approximately 200 times the square footage of a standard cage. It was also constructed to be scenic, comfortable, and friendly (coed groups of 16 to 20 rats). A means was developed to measure each individual rat's opiate consumption from bottled solutions. One mode of opiate presentation was the "seduction" procedure, based on the concept that people are sometimes lured into heroin use by an extraneous payoff. In the rodent microcosms, the "seduction" involved a constantly available choice of water and morphine solution. The water in both environments was pure tap water, but the morphine solution was sweetened. Every 5 days the sweetness was progressively increased toward levels that should be irresistible, since all rats have a powerful "sweet tooth." Whereas Rat Park rats resisted drinking the narcotic solution, the caged rats drank plenty, ranging up to 16 times as much as the Rat Park residents in one experimental phase, and measuring 10 times as much in some other phases. The females drank more morphine in both environments. These animal findings are compatible with the new "coping" interpretation of human opiate addiction. Solitary confinement causes extraordinary psychic distress in human beings, and it is likely to be just as stressful to other sociable species; this elicits extreme forms of coping behavior, such as the use of powerful analgesics and tranquilizers. 6 notes