Scientists working in the fields of neuroscience have learned a lot about the brain, although there is still much that we do not understand.
The brain is intimately involved in all aspects of our day-to-day living. It operates in everything we do, from simple tasks like watching television, to complex tasks like rocket science. The brain takes in information from the environment, analyzes it, and gives us a plan of action for dealing with that information. Within the brain, there are areas specialized for certain jobs, but all of these parts work together to produce the whole. A problem in one small part of the brain can have big consequences, including the development of a serious mental illness.
The brain itself is made up of many millions of cells. Neurons are an important type of cell within the brain. Like the brain as a whole, these cells work to accept information, process that information, and then perform some action in response to that information. Neurons do not act in isolation; rather, they are connected to many other neurons. Neurons communicate with one another using chemicals called neurotransmitters. There are many different types of neurotransmitters in the brain. They include glutamate, GABA, dopamine, serotonin, norepinephrine, and acetylcholine. Problems with certain neurotransmitters are believed to be associated with specific illnesses. For example, too little dopamine is associated with Parkinson’s disease, and too much is associated with schizophrenia. Problems with serotonin and norepinephrine are associated with depression and bipolar disorder. The location of communication between neurons is called the synapse. Most of the psychiatric drugs we use act by modifying chemical communication at the synapse. The neurons’ long-term adaptation to these changes likely underlies the beneficial effects of these drugs.
Mental illnesses are like other illnesses. They are based in abnormal biology affecting an organ system. In the case of mental illness, that organ system is the brain. Mental illnesses are not a result of character flaws or moral weakness. They are true medical diseases, just like diabetes, hypertension, heart disease, asthma, cancer, or arthritis. People with mental illness need to be treated with the same level of concern and respect as we treat people with any other medical condition. The hope is that a better understanding of brain biology coupled with increasingly effective treatment will lead to the eradication of the stigma of mental illness.
DISEASES
Alzheimer’s disease (AD), the most common and fastest growing form dementia in the aging population, accounts for more than 60 percent of all dementia-related diseases.
Irreversible and progressive, AD slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks of daily living. Although treatment can help manage the symptoms of AD, there is no cure for the disease.
According to the Alzheimer’s Association, more five million people are currently living with the disorder. By 2030, that number is expected to increase to nearly eight million.
What causes AD?
AD begins deep in the brain where healthy neurons begin to work less efficiently and eventually die. This process gradually spreads to the brain’s learning and memory center—the hippocampus—and other areas of the brain, which also begin to shrink. At the same time, beta-amyloid plaques and neurofibrillary tangles begin to spread throughout the brain. Scientists believe these brain changes begin 10-20 years before the signs or symptoms of the disease appear.
Primary brain tumors, in which the cancer originates in the brain, account for 50 percent of brain tumors. Secondary or metastatic brain cancer, in which cancerous cells have spread to the brain from a tumor located elsewhere in the body, accounts for the other cases. Twenty to thirty percent of patients with metastatic cancer–cancer that spreads from its origin–develop secondary brain cancer.
Approximately 100,000 cases of secondary brain cancer are diagnosed each year in the United States to the American Cancer Society, more than 22,000 Americans will be diagnosed with brain cancer in 2011 and more than 13,000 will die from the disease. The annual incidence of brain cancer in this country is 15–20 cases per 100,000 people. The disease is the leading cause of cancer-related death in patients younger than age 35. The annual incidence of primary brain cancer in children is about 3 per 100,000.