Mouse research links adolescent stress and severe adult mental illness

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Working with mice, Johns Hopkins researchers have established a link between elevated levels of a stress hormone in adolescence—a critical time for brain development—and genetic changes that, in young adulthood, cause severe mental illness in those predisposed to it.
The findings, reported in the journal Science, could have wide-reaching implications in both the prevention and treatment of schizophrenia, severe depression and other mental illnesses. 

“We have discovered a mechanism for how environmental factors, such as stress hormones, can affect the brain’s physiology and bring about mental illness,” says study leader Akira Sawa, M.D., Ph.D., a professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. “We’ve shown in mice that stress in adolescence can affect the expression of a gene that codes for a key neurotransmitter related to mental function and psychiatric illness. While many genes are believed to be involved in the development of mental illness, my gut feeling is environmental factors are critically important to the process.” 
Sawa, director of the Johns Hopkins Schizophrenia Center, and his team set out to simulate social isolation associated with the difficult years of adolescents in human teens. They found that isolating healthy mice from other mice for three weeks during the equivalent of rodent adolescence had no effect on their behavior. But, when mice known to have a genetic predisposition to characteristics of mental illness were similarly isolated, they exhibited behaviors associated with mental illness, such as hyperactivity. They also failed to swim when put in a pool, an indirect correlate of human depression. When the isolated mice with genetic risk factors for mental illness were returned to group housing with other mice, they continued to exhibit these abnormal behaviors, a finding that suggests the effects of isolation lasted into the equivalent of adulthood.

Written By: MedicalXpress
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10 COMMENTS

  1. There doesn’t sound like this is new.First break psychosis is usually preceded by stressful events. Looking at the circumstantial data could tell us this. Have they identified the so called stress hormone? , have they identified the physiological abnormalities that cause severe mental illness?, have they identified the chemical properties of mental illness? Is it a result of mutation like cancer? What does this research tell us?

  2. In reply to #2 by Pauly01:

    There doesn’t sound like this is new.First break psychosis is usually preceded by stressful events. Looking at the circumstantial data could tell us this. Have they identified the so called stress hormone? , have they identified the physiological abnormalities that cause severe mental illness?, have they identified the chemical properties of mental illness? Is it a result of mutation like cancer? What does this research tell us?

    It seems you did not read the article, it answers your questions. Perhaps you didn’t see the clickable text at the bottom of the blurb. It takes you here:

    http://medicalxpress.com/news/2013-01-mouse-links-adolescent-stress-severe.html

  3. I’ve been watching this story grow over the years, this is some of the best epigenetic research being done, in terms of prudence and being Lamarkian free. I’m very excited to see they are looking at cortisol. I’ve had my own theory about cortisol and epigenetic variation, and I’ll win a bet when they link morphological changes in the hypothalamus-pituitary-adrenal axis to stress-induced epigenetic variation, and then tie that to suicidality and risk-taking behavior in males prior to the age of 30 (hence my nickname for it Logan’s Syndrome).

    Pardon me. My nerd glands are fully swollen right now.

  4. I wonder if isolated human adolescents playing video games might incur similar harmful stress.

    Most on-line multi-player games have a social element, but they might be an inadequate substitute for normal real life relationships. Pretty much any movie or other video entertainment is available on demand, along with computer games for any conceivable interest. So boredom is no driving potentially isolated adolescents out into the real world.

    Also it’s not so much any particular stress as the lack of mild and intermittent stress from social relationships which unbalances the body’s response and resilience to stress hormones.

    If it’s a problem then there will be a mental health epidemic approaching soon. There was a law change in Australia recently attempting to keep kids in school until the age of 18. There being a growing problem with kids dropping out of school after the minimum age of attendance and then virtually doing nothing for years.

    And unrelated: The mere existence of mice are also themselves a form of intrinsic stress to some people.

  5. In reply to #5 by Pete H:

    Suicidality in mid to late teens is revealed here.

    The higher rates in the likes of Japan (compared with Europe) are often explained as the result of exam performance stress.

    It is notable how high the US and Australia are compared with say the UK. Many additional mechanisms play into stress in this period (and crucially just before). In the US it could be concerns of looming adult responsibility given the poor welfare provision for slow starters. It could simply be a culture of greater competitiveness between peers. It could also be a parental reluctance to seek help for “mind things” given the structure and costs of health insurance ($7k/person in the US, typically $3.5k/person in Europe). (I really don’t know what private health insurance policies might or might not cover regarding psychological therapies). Australia is more of a puzzle though I was going to suggest a machismo “tough it out” expectation, but it is the USA with very high male to female ratios (5:1)

    I have always felt that life defining exam pressures on adolescents is a mistake. I feel that during adolescence it would be wiser retaining education for its own sake, laying out the delights of the world for kids to contemplate and take their time over selecting. Life defining exams should not be an issue until 18. Before then the Finnish model of depending on teacher based assessments could yield happier healthier individuals.

  6. In reply to #5 by Pete H:

    I wonder if isolated human adolescents playing video games might incur similar harmful stress.

    http://en.wikipedia.org/wiki/Hikikomori

    I’m partial to the PTSD explanations for Hikikomori Syndrome. As well, a lot of the literature I’ve seen examine isolation as an exacerbation of the stress, involving learning models. This would be similar to how PTSD can lead to risk taking behavior as it alleviates symptoms, but also worsens the conditions in the long run.

  7. Replying to Phil Rimmer and This is Not a Meme:

    Australia might be less of a puzzle than it appears.

    Another parent doing the sailing rescue patrol for the kids around Broken Bay mentioned that the sailing clube and surf club rescue guys further south the North Shore beaches of Sydney often pull bodies out of the water at this time of year. They’re always about the same age and of Asian appearance.

    The mid to lower North Shore of Sydney is closest to Chatswood CBD area, which is pretty much now a reasonably large and exclusively Asian enclave. Which makes the area attractive Chinese migrants unable or unwilling to learn English.

    This is around the time when the university entrance exam results come through, plus offers from universities for various course options.

    There’s a category of kids who are very young (late teens), mostly boys, have been living independently in their own houses or apartments for most of their senior high school years, who don’t speak English well, don’t get out much, play virtually no sport (except computer games), whose parents live in Hong Kong or China or elsewhere in SE Asia, who are from a highly face-oriented culture, and whose parents are paying for everything (whether or not they can really afford it) and have extremely high expectations that their offspring will specifically become medical doctors or lawyers at least. Pretty much nothing else is acceptable.

    They may be Hikikomori kids, straight out of the pressure cooker school environment. Though this might now be a Chinese rather than exclusively Japanese phenomenon.

    Owing to this distorted demand courses that are actually more academically challenging, like advanced maths and advanced science, can be easier to gain admittance to compared to the higher social status programs.

    Suicide is a complex issue, but the number of young bodies of Asian appearance floating off Sydney’s beaches might not be. There’s been some debate recently about reviewing the news suppression policy about suicides. Because there’s evidence that media coverage encourages more suicides, but there’s also evidence that the lake of media coverage leads to the problem perpetuating as there’s no political awareness of the issue.

    A complication might be that New South’s Wales university admissions ranking system is so incredibly complex that no sane human being can make head or tail of it. For kids in the middle ranks of academic capability or performance then simply doing the hard work in the final year doesn’t necessarily lead to positive results. The kids need to have to attended the right school, gone to the right weekend homework classes, taken exactly the right combinations of courses which are preferentially scaled. The admissions rankings also gets modified year by year to reflect government policy as to university subsidies according to what species of creature is apparently in demand by ‘the market’ – whatever the relevant govt deems that to be.

    So it’s possible, at least in in Sydney, that socially isolated kids might be able to delude themselves that they were doing OK and have even sat the exams feeling they’ve well. They might not find out they’ve trashed their entire families hopes and dreams until the official results are released. Combine that with their acute awareness of the time they’ve obsessively invested in computer games and things sometimes don’t turn out well.

  8. In reply to #9 by Pete H:

    So it’s possible, at least in in Sydney, that socially isolated kids might be able to delude themselves that they were doing OK and have even sat the exams feeling they’ve done well. They might not find out they’ve trashed their entire families hopes and dreams until the official results are released. Combine that with their acute awareness of the time they’ve obsessively invested in computer games and things sometimes don’t turn out well.

    That’s brought me out in a cold sweat!

    Thanks for this explanation. It certainly looks like a possible contributing fact.

    Looking at the detailed data for all suicides in Australia I see that with 180 suicide attempts per day only 6 are successful. It may be that attempts may be a more revealing statistic of stress than actual suicides.

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