2007-09-14
The brain is a work in progress, and adolescence is the last great time of major brain development and change. Now the drama of brain development focuses on the part of the brain that makes us who we are: the prefrontal cortex which allows us to make future plans and it is involved in highly abstract areas like personal responsibility, morality, and self-control. And this part of the brain is undergoing major development.
Two years ago, ... was struck by schizophrenia, a brain disease that adolescents are vulnerable to. "I spent 19 years with virtually the same personality and I was accustomed to it and I liked it, I liked being me, you know, and all of the sudden it was taken away." "He would come up to me and he would say, 'Mommy you look like a really old lady today'." He would describe tunnel vision. "When he would open his eyes in the morning, he would have all of these visual disturbances." "They are usually in the very center of my vision, and uh, but it varies, like now, they're just kind of where I see the sky, you know, they're still there." "I think it took him a number of weeks to come to me. He was terrified."
"Schizophrenia is an enigma. It has never been possible to identify an obvious schizophrenia condition .. there's no anatomical clues. What has gone wrong inside the brain of schizophrenics? New imaging technologies has found how the brain fails to function properly." Focusing attention on several underperforming areas works, like in reasoning, memory, intelligence, etc., and the fact that so many regions are malfunctioning has led investigators to research the prefrontal cortex- it functions like the conductor in an orchestra and it maintains harmony and makes music out of many disparate elements of this orchestration and part of the problem when the prefrontal cortex is deficient, instead of music it makes noise.
"I have a little bit of trouble staying coherent, uh, staying to one particular subject, uh, because my mind is somewhere else." A poorly functioning prefrontal cortex makes thinking difficult. It is no surprise that many people with schizophrenia perform not as well on quantified thinking tests. Schizophrenia effects our high-conceptual levels. Scientists thought that MRI would help solve schizophrenia by identifying brain damage, but the images revealed a new mystery: "We were surprised to see that there was no obvious hole in the head, but there was this: the ventricles, with cerebrospinal fluid, were slightly bigger in schizophrenic brains." Why are they larger? The oversized ventricles proved to be evidence that other areas of the brain would have had to be smaller.
"The only way that all of this could stay inside your head, well, something else would have to be smaller."
What triggers the onset of schizophrenia? The adolescent brain is far more flexible and adaptable than we ever realized before. There is enormous potential for change. There's the ability to anatomically change. At the beginning of adolescence, the prefrontal cortex goes through a burst of growth, where the neurons reach out with dendrites to spawn new synapses. As they grow, the neuronal connections grow stronger, and so this is nature's way of pruning out the bad stuff. The way to prune neurons is based off of the activities of the teenager. The brain is searching for "what am I going to need to be good at to survive, so what am I doing now."
Adolescence is when the prefrontal lobe is fighting to deal with inner-instictual surges, and it's difficult with prefrontal cortexes to make it through adolescence, and in schizophrenia perhaps the prefrontal cortex did not develop normally earlier in life. Are there clues to schizophrenia during childhood for later adolescent failure? Psychologist Elaine Walker is trying to answer those questions by examining home movies of children who later developed schizophrenia.
A good place to look is at motor development. So observe the videos and you see some patterns. Normal children develop symmetric crawling, and schizophrenics tend to have asymmetrical crawling patterns. The problem could occur at just months after conception. As neurons are born, and join together, scientists see the possibility for error. The genetic makeup of the brain, poor nutrition, a viral infection, all of these may have devastating effects. Whatever the cause, the damage lies dormant until the prefrontal cortex goes through its final maturation, and so schizophrenia could be a disease where the final stage of development goes amuck.
Schizophrenia disrupts not only thinking, but it also has a severe impact on emotions. Researchers flash a series of images on the screen, and then watch the response of the brain. Usually, the brain is activated in regions where emotions are processed, but in schizophrenia these regions respond poorly. People with schizophrenia will very often say, "I feel like I cannot feel related to the world at all." It's both intellectual and emotional. It's one of the factors that drives schizophrenics towards suicide. The thing that really crushed me was the lack of motivation, the negative symptoms of schizophrenia, the emotionalnessless, the apathy, those were the things that really got to me. He would talk frequently about not being able to feel anything, no sorrow and no joy, there was just nothing there. I didn't want to live the life that I had been given. It was so contrary to what I wanted that I didn't want it anymore. When I heard that Courtney had attempted suicide, he had talked about it and he had ideas, and he was one of the individuals that understood that he had an illness. He wrote a suicide note because of his poor quality of life, but didn't succeed at suicide (this surprised the psychologists).
Other teenagers with schizophrenia suffer from voices, visions, etc. Here's a person who had negative voices. "Now 14, Sabrina has been struggling for 2 years to stay in touch with reality. Hallucinations haunt her waking hours. Sabrina often sees a black, hooded dressed figure, that will sometimes just stare at her, or talk to her, or try to touch her, or kill her, or when she struggles, they begin to chant and say 'Kill yourself, do it, do it.'".
How do hallucinations overwhelm the adolescent brains? Maybe there are drugs that can treat these psychotic symptoms. Isaac Wallace began to hear voices when he first went off to college. He grew paranoid and was finally hospitalized for his own protection. (Diana Perkins). The voices that Isaac heard were disturbing, because they sounded so very real, but his brain was malfunctioning. Sounds go towards the auditory cortex which go to the thinking portions of the brain. In psychosis, neurons fail and sounds are made that have no connection to the outside world, so there's this perception of sounds that do not exist. So when the brain circuitry is out of whack, it is just as if you are hearing the radio on. Scientists theorize that psychosis is caused in part by dopamine. In the normal brain, dopamine works by stimulating receptors, sending off a cascade of electrical and chemical reactions, in psychotic brains, the levels of dopamine surge, and over stimulate the receptors and reck havoc in the brain.
Since the 1950s, antipsychotic medications have been standard treatment for treating psychosis. For Isaac, these drugs have worked wonders. Antipsychotic medications block dopamine receptors and thus there is less neuronal stimulation. How did this improve Isaac's situation, though? How did he gain concentration and a better memory with less neuronal stimulation?
Every year, 300k Americans are diagnosed with schizophrenia, many in their teens. But millions of teenagers have another problem. Teenagers are beginning to explore the world on their own. Their reasoning skills are still not fully developed, which is especially risky when they experiment with drugs. 12 and one half million Americans suffer from drug problems (teenagers). Adolescence is a time when they will probably encounter drugs. Addiction is a disease of the brain that effects thinking, emotion, and behavior, and in that sense, it's like many other serious brain diseases, like depression, like schizophrenia, except that here the pathogens are the drugs of abuse themselves acting on a normal brain.
"I never thought I would ever become an addict until I really started doing coke, not just weed, not just alchool, but cocaine, and it was getting worse and worse." She started experimenting with alcohol and marijuana at 11, and by 16 she was addicted to cocaine, she had to have it to function, to get out of bed, she couldn't get out of bed without doing cocaine first, and she couldn't walk into the school without her cocaine, and she had to do it to live, and she knew she had to fix it or she would die. By 17, caught in a desperate problem, she went to a drug reshab center. Here, teen addicts try to regain control over their lives after having been captured by addiction. "I didn't have control: drugs had control." "One day I was sober, I had nothing to drink and nothing to smoke, and it was for the first time that I had nothing in my system." Addiction used to be viewed as a weakness in character, a moral problem, but now we are figuring out that addiction gradually takes control of the brain, like desire.
The neural circuitry in the reward pathway is a network where our desires and pleasures are based, are the neurotransmitters that one neuron uses to talk to another. Addictive drugs work by altering the level of these neurotransmitter and slyl capturing the reward pathway. All addictive drugs are Trojan horses, and every single one of the chemicals that are addictive, are neurotransmitter mimic- they look like one of the chemicals that the brain uses to work. Dopamine is one of the most powerful reward neurotransmitter, which normally travels across the synapse, stimulates receptors, and is then absorbed by dopamine transporters, but when cocaine molecules are used, cocaine clogs the vacuum-cleaner dopamine transporters, and causing dopamine to surge in the brain, known as a cocaine high. Cocaine gets into the brain chemically, and gives these synapses more dopamine for a longer amount of time than it has ever experienced before, and with the experience of the first drug-high, particularly cocaine and heroin, dopamine levels ascend above and beyond the greatest physiological experience that we can have as women and men. Once the drugs are introduced into the addictive brain, the natural system is what we call downregulated- the things that are supposed to work for exercise and food, well, they go into hiberation, and you have a feeling of hoplessness, such that the only thing you could do is readminister the drug to get anything near that high or pleasure. After repeated drug use, the dark side of addiction begins to take its toll. The brain responds to dopamine surges by fighting back: cutting off receptors. Without these receptors, dopamine can't be used, so there's this lack of normal pleasures now.
The drug can trick people into thinking they like their lives. "Something about these genes, about their temperment that made them vulnerable, so they got hooked- something different about their brains that played against them." Like cocaine, alcohol is dangerously addictive. By their senior year in high school, 9.5 million teens would have tried it. What makes some of these teens more vulnerable to alcohol than others? For volunteers, he has one night of drinking down to ten minutes. Their blood-alcohol levels were virtually identical. What the brain waves show is that some people respond differently than others with the same blood-alcohol levels. So different levels of alcohol cause different levels of drunkness in different brains.