考研阅读精选：心理压力的恶果
The vicious physiology of stresshttp://images.koolearn.com/casupload/upload/fckeditorUpload/2011-11-21/image/b8d74964359d4fb8aa18d3c706071360.jpg
One of my favorite parts of this job is stalking busy scientists researching different aspects of stress.
I recently tracked down the brilliant Dr. Rajita Sinha, director of theYale Stress Center, and spoke to her about what she’s working on. Inthis first part of our conversation, we discussed the physiology ofstress and its connection to maladies, ranging from addiction to chronicdisease, diabetes and obesity.
How did you come to study stress?
Early on I was working with different types of emotions - anger andsadness - and how they affect the body and change our responses todifferent stimuli in the environment. One of the things I observed wasthat generally people don’t have pure emotions, like anger or fear.
They mostly have mixed emotions. If you ask them about it, they willsay they’re stressed and upset. I wanted to understand how emotions worktogether - both to protect us and to feed into things that wear usdown.
Is there such a thing as good stress?
Thinkabout good stress in terms of adaptation. Every time you overcome achallenge and learn something from it, it leads to cognitive andbehavioral adaptation. It’s like skill building. When a challenge isfrustrating but within our ability to handle it, you are talking about agood stress. It’s stress that is sustained, uncontrollable andoverwhelming, where people can’t figure out options to solve theirproblems, that is damaging.
.
Can you tell me about the link between stress, chronic disease and addictive behavior?
We’ve known about the link between stress and addiction, and increasedsusceptibility to chronic diseases for a long time. But we have notfully understood the biological mechanism until recently.
When we experience something threatening or stressful, two things happenimmediately. The first thing is what we call the "fight or flight"arousal response. The whole body is gearing up to move quickly to getout danger. And the second thing is that the body releases the stresshormone cortisol. The body gears up immediately in the face of stressfulstimuli. It goes to our energy stores, and releases glucose and insulinso that our muscles have the energy to deal with the stress.
Here’s where the rubber hits the concrete, in terms of our choices.Drugs like alcohol, nicotine and cocaine, and also high-fat,high-calorie comfort foods, are powerful modifiers of the stress system.They will change our stress pathways and affect the way our body isable to control our stress response. And so, after a period of bingeing,your body’s stress system eventually just wears out.
Youradrenal gland, which is responsible for releasing the stress hormone,becomes weak or sputters out. Then it doesn’t signal properly to help uscope. That, in turn, starts to affect us adversely - not just ourbiology, but also our emotional response.
Can you reinvigorate worn-out adrenals?
There is evidence that you can reinvigorate your adrenals. Once alcoholdependents start recovering, after some time has passed, you startseeing adrenals returning to normal. We know less about how long ittakes.
The problem, though, is that while your adrenals arestill recovering, you are more likely to be stressed. And stress affectsabstinence and increases chances of a relapse. So then you are caughtin a vicious cycle of quickly degenerating health because both thestress and the substances are working together to wear down your bodysystems—your stress axis, your liver, kidney, heart, blood pressure.
Then you get a double whammy in terms of risk for heart disease andcertain types of cancer. It’s what we call the feed-forward effect. It’snot going to happen immediately, but it does become a vicious cycle.
Which comes first, the stress or the addictive behavior?
We don’t really know which comes first, but we do know that these areall complex multi-factoral diseases. That means they don’t have onesingle factor that leads to the disease state. And there are factorsthat can make a person even more vulnerable to stress-related diseasesand addiction: early trauma suffered in childhood, cumulative adversity,socio-economic status, education and also things like genetics andpersonality traits.
Which aspect of your research are you most excited about right now?
We’re about to release a paper about how cumulative adversity - thenumber of bad things happening in one’s life - appears to have an effecton the size of the brain’s prefrontal cortex.
What does that mean? Is that a good or bad thing?
It means the higher number of bad events, the smaller the size of theprefrontal cortex. And our animal studies show that less volume in theprefrontal cortex is not good behaviorally. Neurons start shrinking andlose their branches and dendrites. Those animals don’t do well indifferent kinds of cognitive tasks. So what that means is that higherlevels of adversity affect our ability to respond to acute stresssituations.
It has two effects: There is less brain volumeand the regions that help us adapt and cope are underactive.The morelifetime adversity, the higher amount of chronic stress that a personfeels. Then the risk for stress-related disorders go up: heart disease,diabetes, certain types of cancer, psychiatric and neuropsychiatricdisorders like depression, anxiety and addiction.
Well, that’s depressing for those of us who’ve been through a lot in life through no fault of our own.
An interesting follow-up is that the brain is very dynamic and theremay be potential for normalizing or regrowth. The studies we did arewith people between 18 and 50. These are our most generative years, sowe hope we can intervene, through treatments, to turn the course.
How can we train ourselves to respond better to stressors?
We live in a society where there are multiple demands on us almost allthe time. We need to put greater emphasis on protective factors likesitting down with the family or exercising or putting away all theelectronic devices.
I am also a big believer in mindfulness. Ithink we need to be able to turn things down and off, and build inprotections so that we don’t get overwhelmed - even something as simpleas a hobby.
I was on a show once where someone had joined adrumming class to relieve stress. It’s a matter of taking the time tobuild in positive aspects to our life, our actions and our exposure.That’s like money in the bank.
页:
[1]