The Teen Brain on Weed

April 24, 2015

By Medical Discovery News

A brain

It is now legal to use marijuana (recreationally and/or medically) in more than 20 states and the District of Columbia, and as more places debate legalizing the substance, more people are asking about its consequences on human health. There are many myths and misconceptions out there, but this is what science has to say about the subject.

As with all substances, the health effects depend on the potency, amount, and a person’s age. An independent scientific committee in the United Kingdom evaluated how harmful various drugs were based on 16 criteria and ranked heroin, crack cocaine, and methamphetamine as the most harmful drugs to individuals using them, and ranked alcohol, heroin, and crack cocaine as the drugs that cause the most harm to others. Marijuana ranks eighth, with slightly more than one-quarter the harm of alcohol.

Short-term use is associated with impaired short-term memory, making it difficult to learn and retain information while under the influence. Short-term use can also impair motor coordination, interfering with tasks such as driving. The overall risk of an accident doubles if a person drives soon after using marijuana. In comparison, those with blood alcohol levels above the legal limit are five times more likely to have an accident, and the combination of alcohol and marijuana is higher than either one alone.

Long-term or heavy use is associated with diminished life satisfaction and achievement overall. At high doses, marijuana can cause paranoia and psychosis, and long-term marijuana use increases the risk of developing schizophrenia or other chronic psychotic illnesses. Nine percent of all marijuana users, or 2.7 million people, develop an addiction to it. That figure jumps to 25-50 percent for those who use marijuana daily, and 17 percent of people who begin using marijuana as adolescents become addicted. Cannabis withdrawal syndrome is real and includes symptoms of irritability, sleep disturbance, dysphoria, craving, and anxiety.

Adults who occasionally use marijuana do so with little to no risk, but adolescent brains are not fully developed, making them more vulnerable to the adverse effects of marijuana. Using marijuana during adolescence can alter brain development, causing impaired cognition and lower IQs. This is probably because the active ingredient in marijuana, tetrahydrocannabinol, affects the brain’s ability to make connections between neurons in certain regions of the brain. Adolescent marijuana users also have a smaller hippocampus, which is important in learning and memory, and a less active prefrontal cortex, which is important in cognitive tasks such as planning and problem-solving.

Since acute marijuana intoxication can impair cognitive functions for days, students who use marijuana may function well below their natural abilities, causing academic difficulties. High school dropouts do report higher marijuana usage than their peers. Some evidence suggests that these cognitive impairments could be long-lasting or permanent in long-term users who started at younger ages, which can impact their abilities to succeed academically and professionally.

There is no clear association between long-term marijuana use and any deadly disease, although chronic marijuana smokers have increased rates of respiratory infections and pneumonia and an increased risk of heart attack and stroke. The effects of marijuana on a developing embryo and the effects of second-hand or third-hand marijuana smoke have not been well-studied, but as marijuana legalization continues to be an issue the science behind it will as well.

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A Top 10 List To Die For

Sept. 13, 2013

By Medical Discovery News

How are you going to die?

The Centers for Disease Control would answer that life expectancy depends greatly on where someone lives. Life expectancy in the United States ranks 40th in the world with 77.97 years.That addresses when someone might die but what about how? Most likely, it will be from one of these top 10 causes, based on how many Americans they kill each year.

10) Suicide – 38,285. Many factors are now known to influence suicide: mental illnesses, genetics, certain pharmaceuticals, traumatic brain injuries, drug and alcohol abuse, and chemical or hormonal imbalances. To decrease these rates, education about the signs preceding suicide and accessible treatment is necessary.

9) Kidney Disorders – 45,731. Although dialysis can help people survive a little longer without a kidney, it is no cure. Kidney damage can occur from infection, high blood pressure, or toxic reactions to drugs, leading to chronic kidney disease that affects more than 26 million Americans.

8) Influenza and Pneumonia – 53,667. Both these diseases mostly affect the very old, very young, or those with immune system problems. This figure could be lowered with vaccinations.

7) Diabetes – 73,282. The rate of diabetes is increasing, with one in 500 children being diagnosed, corresponding to trends in obesity, diet, exercise, and aging. Lifestyle changes could decrease diabetes rates.

6) Alzheimer’s – 84,691. This form of dementia affects older adults, mostly over 60, and is caused by the build-up of beta-amyloid protein plaques in the brain. There is currently no cure.

5) Accidents – 122,777. The leading cause of accidental deaths depends on age. For children and young adults it’s car accidents, adults over 35 are most likely to accidentally overdose on drugs, and for those over 65 it’s most likely to be related to a fall.

4) Stroke – 128,931. A stroke occurs when an area of the brain does not receive oxygen due to a ruptured or blocked blood vessel. Those with high blood pressure, diabetics, smokers, and alcoholics are at the highest risk. The good news is that deaths from strokes decreased by almost 45 percent in 10 years but still leads to more than 250,000 hospitalizations yearly.

3) Chronic Lower Respiratory Diseases – 143,382. These diseases of the lungs and airways include bronchitis and emphysema, although the latter kills 20 times more than the former. Smoking is the leading cause of this condition.

2) Cancer – 575,313. Lung, colon, breast, pancreatic, and prostate cancers have the most victims out of more than 200 different types affecting more than 60 different organs. Another piece of good news is that five-year survival rates have increased about 15 percent since the 1970s.

1) Heart Disease – 596,339. Advances in science have improved care, reducing these deaths by 18 percent in 10 years. However, as 25 percent of adults have high blood pressure, 67 percent are overweight, and 20 percent smoke, Americans have plenty of risk factors to improve on.

The United States has maintained its leadership role in biomedical science and needs to continue this in the future. Support biomedical research – your life may depend on that next scientific advance.

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Aging But Still Protected

June 14, 2013

By Medical Discovery News

The people who are at the highest risk of dying from common infections like pneumonia, influenza, and colds are 50 and older. Traditionally, scientists believed that as we age, our immune systems weaken, leaving us more vulnerable than ever to infections. But new research suggests that this isn’t completely true – certain parts of the immune system remain fully functional and robust longer.

It is true that older people make fewer antibodies, proteins that attach to viruses and cells infected with viruses to mark them for elimination by the immune system. This explains why some vaccines aren’t as effective in the elderly. The flu vaccine, for example, contains a “dead” virus that stimulates the body to make more protective antibodies against the flu.

However, other vaccines are well-received in older people, like the varicella zoster virus vaccine that prevents shingles. This vaccine does not involve antibodies, but T-cells, which kill infected cells, and memory T-cells, which recognize and respond to a reinfection.

White blood cells, formally called leukocytes, represent an army ready to defend the body from bacterial or viral attacks. T-cells are one type of soldier in this army, responsible for cellular immunity – killing infected cells to protect the body. The thymus, located between the breast bone and heart, produces T-cells. But as people age, the thymus does too.

The thymus shrinks by about 3 percent a year during middle age, and there is a corresponding fall in the production of T-cells. As humans age, their T-cells increasingly become memory cells. Therefore, it’s been assumed that the T-cell response to kill cells infected with a virus is impaired in older adults, making them more susceptible to viral infections.

To test that assumption, researchers at the McMaster Immunology Research Centre in Ontario isolated blood from people with one of three types of viral infections: West Nile Virus, Epstein-Barr Virus, and Cytomegalovirus. They divided the patients into three groups: those under 40, those middle-aged (41 – 59), and those over 60. They then measured the amount, type, and activity of the T-cells in each group. The older group did indeed have a shift toward the production of memory T-cells. But surprisingly, the amount of virus-specific T-cells did not decrease with age – the older group had roughly the same amount as the middle and younger groups.

These results suggest that the thymus continues to play an important role in producing T-cells that target viral infections as we age. It also indicates that vaccines designed to stimulate cellular immunity, instead of antibodies, would be more effective in older people. So the flu vaccine might prevent more flu cases in older people if the dead virus was replaced with a live but weakened virus, but currently that’s not approved in the U.S. for people over 50.

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