According to researchers from the American University of Ohio sexual intercourse in adolescence is fraught in the future with disorders of immunity and susceptibility to depression.
Scientists evaluated the impact of early sexual life on the well-being of hamsters, which are considered physiologically quite close to man. Males of different ages mated with adult females; some males were 40 days old, which corresponds to the middle of adolescence, others were already quite mature, aged 80 days. The experimenters carefully monitored the sexual encounters that took place during the six hours of intersexual intercourse. Later 40 and 80 days for each group of males physiological condition of animals was estimated.
First of all, behavioral tests were carried out: the animals were placed in a maze where they could either explore new territories or sit still. In addition, there was still water maze, where the hamsters had to get out on the floating island. In both groups, males showed signs of anxious behavior under stress, but those who learned the delights of sex early were more depressed: they were afraid to go beyond the familiar corner and quickly gave up when it was necessary to find a land plot in the middle of the water. Changes were manifested at the cellular level: early sexual nerve cells in areas of the brain such as the amygdala, prefrontal cortex, hippocampus and striatum, were arranged simpler. Dendrites, the processes of the neuron, on which the nerve cell receives «incoming data» were poorly branched and formed fewer synapses (intercellular contacts).
On the other hand, in the same parts of the brain there was an increased activity of the immune genes responsible for the inflammatory response. The immune protein interleukin-1 serves as a signal to start and maintain inflammation when it is required to expel infection. But those individuals who had sex in adolescence, the activity of the gene interleukin-1 in adulthood was increased in itself. And without infection, it is fraught with causeless inflammation and the development of autoimmune diseases. The same was confirmed by a test for immune response in these animals. The immune system was on edge and could start to attack the body's own tissues at any moment. Finally, the animals «from the early group» showed in adulthood lower body weight and a decrease in the reproductive tissues and organs (seminal vesicles, VAS deferens and testis appendages).
The above-mentioned areas of the brain mature longer, their adjustment lasts until maturity in hamsters and in humans. The sexual system is formed much faster, the same hamsters become sexually mature in 21 days of age. The authors believe that the immature nervous system perceives sex primarily as stress, and therefore forms a long-term response to it: weakens the sexual system, overexcites the immune system, trying to protect itself from stress signals.