WEDNESDAY, Aug. 31 (HealthDay News) -- Animal studies
suggest that the use of opiate drugs, which include
morphine and heroin, can leave users more vulnerable to
stress, creating a vicious cycle of use and abuse.
Not only does stress trigger
the drug use, but in return the drug leaves animals more
vulerable to that stress, researchers at the University
of New South Wales report in the current issue of
In the study, scientists
injected rats with either morphine or a saline solution
for 10 days. They then performed a stress test on them
by gently restraining each rat for 30 minutes.
In the absence of stress,
opiate-treated rats behaved the same as the other rats.
But when subjected to stress, they appeared to suffer
twice as much as non-drugged rodents.
The longer the duration
or the higher the dose of morphine, the greater the
difference in this stress reaction, the researchers
The research could
explain why people who use opiates such as heroin have
very high rates of anxiety problems, including
post-traumatic stress disorder, even after they stop
using, researchers said. That emotional fragility also
can also make them more likely to start using again, the
Australian team said.
The National Institute on
Drug Abuse has more about
American Psychological Association, news release, Aug.
Last Updated: Aug-31-2005