Pregnancy stress makes children susceptible to addiction
Stress during pregnancy has a significant impact not only on the mother's body but also on the children's organism. Now Portuguese researchers have shown in animal experiments that brain anomalies similar to those in drug addicts can be caused by prenatal stress in unborn children.
To what extent the results of the scientists from the University of Minho in Braga published in the specialist magazine "Molecular Psychiatry" can also be transferred to people remains unclear. Quebec, however, will soon be able to investigate the long-term effects of pregnancy stress on unborn children. Because here in January 1998 the electricity was out of action for weeks during an ice storm and since then researchers in the "Project Ice Storm" have been watching the development of the children who were born during the power cut.
The Portuguese scientists Ana João Rodrigues and Nuno Sousa from the University of Minho have found in their current research that the offspring of rats showed significant brain abnormalities when the mothers were exposed to an increased level of stress hormones during pregnancy. The changed patterns in the brain are similar to those of drug addicts and suggest that children, whose mothers are exposed to increased stress during pregnancy, also have an increased susceptibility to addiction, report the scientists in the journal "Molecular Psychiatry". However, the effects of stress hormones in animal experiments could also be reversed, emphasized Rodrigues and Sousa. The patterns in the rats' brains could be normalized again with the so-called happiness hormone dopamine.
Stress hormones cause brain abnormalities In their studies, the researchers injected pregnant female rats with special stress hormones called glucocorticoids before the birth of their offspring, and then observed the effects this had on the brain structure of the young animals. Rodrigues and Sousa found that the offspring of the female rats, which had an increased level of stress hormones, suffered more from brain abnormalities than adult animals. These anomalies were amazingly similar to those of drug addicts and the animals were also more susceptible to addiction to opiates and alcohol, the Portuguese researchers write. However, the effects of stress hormones on the brain could also be revised later in life, with the help of injections of the neurotransmitter dopamine, according to Rodrigues and Sousa. The brain abnormalities were therefore as reversible as the susceptibility to addiction.
Restoring dopamine levels to addiction treatment "This is an amazing result because it suggests that with a relatively simple pharmacological approach, restoring dopamine levels," drug addictions can be treated, said Ana João Rodrigues. "Even more important," according to the expert, is that, based on current knowledge, "potential drug addiction in susceptible people" can also be prevented. However, the Portuguese researchers also emphasized that there is still a long way to go before the method of restoring dopamine levels can also be used as a regular therapeutic treatment. Although the method has already been used on a trial basis in the treatment of cocaine addiction, the results have remained extremely unclear, which is why further research is urgently needed, explained Rodrigues and Sousa. The scientists suspect that the hitherto unsuccessful use of restoring dopamine levels may be due to the length of treatment or the dosage of the happiness hormones. In animal experiments, too, it had been shown that a three-day treatment in the animals whose mothers were exposed to increased stress during pregnancy only had a short-term effect and that the rats showed brain abnormalities and an increased susceptibility to addiction after only three weeks. When the dopamine level was restored over a period of three weeks, the animals did not revert to their original addictive behavior, explained Rodrigues and Sousa.
Long-term study on the effects of prenatal stress In order to better understand the effect of stress in pregnancy on the organism of the unborn child and also to record long-term effects, researchers worldwide hope for the data of the so-called "Project Ice Storm". In this project, Canadian researchers have been recording the data of the children born at the time since the power outage in Quebec in 1998, because the mothers were exposed to significantly increased stress in the weeks without electricity, the basic assumption of the scientists. The researchers observe the development of the children and try to find out how prenatal stress affects their organism in the long term. The Canadian scientists have already identified significant brain abnormalities in the children, who are 13 years old, and in the coming years the connection with addiction susceptibility will also be checked, explained Ana João Rodrigues and Nuno Sousa. At the same time, however, new approaches to treating drug addicts based on the restoration of dopamine levels should already be developed and tested, according to the Portuguese scientists. (fp)
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