Science Makes Sense-Week33: Lithium, the little pill that can

I shall never forget that call from my dear friend who needed me when her husband had a manic episode in the 80’s. Those were the days when I had barely heard of mental illnesses and least of all anything about manic depression/bipolar disorders. On a wintry morning, I drove over to her place to give her some company and comfort. He had been taken in restraints to the hospital. After years of being treated with ‘lithium’ he is the charming intelligent human being I knew before that incident. Now he is able to take care of his family and himself. This ‘lithium’ is chemically lithium carbonate which has been used successfully by several psychiatrists to treat mental illnesses like bipolar disorders.
Lithium,Li, is the first in the alkali metals and is one of the smallest atomic solids on the second period of the Periodic Table. As a metal it is highly reactive, and when added to water, reacts explosively to form the alkali lithium hydroxide.(Ref.1) In nature, lithium is found as a mixture of the two isotopes Li6 and Li7. Soft and silvery-white, Li has a low melting point but has a high specific heat. It seems to behave more like the alkaline-earth metals than the alkali-metals. (Ref.2)
Being very reactive, it does not usually exist as metallic Li but as the hydroxide, LiOH. It is one of the few elements to react easily with nitrogen to form a black nitrite. It reacts with hydrogen at higher temperatures around 500 degrees C to form lithium hydride, LiH. (Ref.2)
Uses: Main industrial uses of Li is as a lubricant grease thickener, in the glazing of pottery and to extend the life and storage of alkaline batteries. Lithium carbonate, Li(CO3)2, is used mainly to treat bipolar disorders. What is bipolar disorder or BD as it is often called? It is a mental condition that causes extreme shifts in a person’s energy levels. The person affected by this disease could be extremely agitated and ‘manic’ with racing thoughts for days/months and then come crashing down feeling major depression and guilt for their earlier actions. These mood shifts are very different from those that everyone else goes through, because people with BD could be totally impaired in their abilities to complete day-to-day tasks when suffering from this disorder.(Ref.3) When Li was discovered in 1817, it was used initially in the treatment of gout and physicians could tell that it was good as a mood stabilizer. The Australian psychiatrist, Dr. John Cade published the first paper on the use of lithium in the treatment of acute mania in 1949, but it was not until 1970 that the U.S.FDA approved it. (Ref.4)
The chlorides and bromides of Li are also used in absorbing humidity and hence in air-conditioning systems. Alloys of Li with cadmium, Cd, manganese, Mg, copper, Cu, are used in the manufacture of high-performance aircraft parts.(Ref.2)
Lithium’s role in the treatment of bipolar disorder or BD has undergone several modifications, but the key role is how it helps in reversing structural abnormalities in the brain/biochemical changes in the brain because of BD.
First Li ions help in decreasing second messenger systems in the brain, protects the nerves in the brain. BD patients have grey matter reductions especially in the medial frontal cortex and the hippocampus regions of the brain; Li ions once again help in reversing these effects. Overall, Li treatment(in the form of lithium carbonate/lithium ions) helps in maintaining the nerve plasticity of the brain. (Ref.5). It is almost as if this tiny metal ion is able to go around the brain and repair problems that cause BD in patients!
Activities for Middle School Teachers:
Students can study the ionic radii of elements in the first three periods and try to understand what the relative sizes of the cations and anions are. Is there a correlation with the increase/ decrease of radii based on the group or period ? Why?Create a graph for each of those periods using ionic radius of the element versus its atomic number. Is it a straight-line variation? How does the size of the lithium ion compare to other elemental ions?
If a model of the brain is available, the teacher needs to spend time talking about the different parts of the brain, including the hippo-campus and the frontal and medial cortices. What are the functions of the various parts of the brain?
Let the teacher spend time talking about several kinds of illnesses versus mental illnesses. Discuss how families are more open to talking about physical illnesses in loved ones versus mental illnesses. How are psychiatrists viewed in societies as opposed to other kinds of medical doctors? Is there a difference? Why?
Nuggets of Information:
Lithium is moderately abundant on the earth’s crust: 65ppm.(Ref.2)
In the U.S.,lithium is recovered from brine pools in Nevada while most commercial lithium is obtained from Chile.(Ref.2)
Compounds of Li and acetylene are used in the manufacture of Vitamin A.(Ref.2)
Bipolar disorder was officially known as manic depression in the 80’s.
The National Institute of Mental Health(NIMH)estimates 2.6% of U.S. adults suffer from BD, which is approximately 600,000 people in the U.S. More than 80% of these cases are classified as severe.(Ref.3)
Research has never indicated that bi-polar illness is because of lithium deficiency; rather that lithium carbonate acts as a mood stabilizer.(Ref.5)

References:
1.http://chemguide.co.uk/inorganic/group1/reacth2o.html
2.http://www.lenntech.com/periodic/elements/li.htm
3.http://www.everydayhealth.com/bipolar-disorder/guide/
4.http://bipolar.about.com/od/lithium/a/010312_lithium1.htm
5.https://www.dnalc.org/view/2085-Lithium-how-it-might-protect-the-brain.html

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