Scientists Find a Recipe for Schizophrenia
The best thing about the rejection of Freudian analysis and the widespread acceptance of drugs for treating mental illness was that it let guilty parents off the hook. We were no longer the source of our children’s phobias, fetishes, depression and psychopathy; the fault lay with our kids’ genes, in their imperfect mental wiring. Thank God. Most parents already haul enough guilt around with them from day to day.
But now comes news of a study in which Swiss scientists were able to induce schizophrenia in mice. And they couldn’t have done it without the mice’s mums.
In the research, performed at the Laboratory of Physiology & Behavior at ETH Zurich, the scientists showed that two separate environmental factors combined in mice to trigger development of brain changes that resemble those found in schizophrenics—changes that manifest at the stage in mouse life that corresponds to early adulthood, which is just when symptoms usually surface in human beings.
The first environmental factor is a viral infection suffered by the mother of the mice—from a simple cold to herpes to toxoplasmosis. According to the scientists, such infections activate immune cells within the central nervous system in the mouse-fetus’s brain, called microglial cells. These then produce cytotoxins that change the way the brain develops. When the mother recovers from her illness, the microglial cells go into dormancy.
In most mice—and people—the story ends there. But when the scientists subjected these mice to chronic, severe stress as they were going through puberty—stressors that equate to sexual abuse or physical violence—the microglial cells resurfaced and again effected changes in the brain. “Evidently,” doctoral student Sandra Giovanoli, who did most of the work on the study, reports, “something goes wrong with the ‘hard-wire’ that can no longer be healed.” The mice didn’t show any immediate signs that anything was amiss, but in early adulthood, they began to act abnormally, with behavior patterns comparable to symptoms of schizophrenic humans; they were less alert to sounds, for example, and showed increased sensitivity to drugs such as amphetamine.
It may seem like a jump from humans to mice, but the study, published in the journal Science, was designed to simulate processes that occur in humans but would take place much faster, since mice have a much shorter lifespan. And control mice showed that only one of the factors—the infection in the mother or the stress in the pubescent mice—wasn’t enough to cause schizophrenic symptoms; the combination and the timing were key. The takeaway, according to senior scientist Urs Meyer: “It isn’t all genetics after all.”
The researchers stress that moms-to-be shouldn’t panic; many expectant women catch colds or flu, and lots of kids go through stress during puberty. There may be genetic factors influencing either stage of the process, making some mothers and/or offspring more prone to the effects of the microglial cells. “A lot has to come together in the ‘right’ time window for the probability of developing schizophrenia to be high,” Giovanoli said. It’s hard to imagine, though, that this study of mice and men won’t cause anxiety, not to mention handwringing. Maybe it’s Freud’s revenge.
