There is a joke that if an intelligent person thinks too much they develop gray hair, while a less intelligent person who thinks too much becomes bald. There is a legend that when Marie Antoinette, the wife of Louis XVI of France failed to evacuate and was due to be executed, she developed gray hair in just one night of mental suffering.
However, does thinking too much really lead to the development of gray hair?
Gray hairs are a symptom of aging. Most people start going gray in their 40s, but some young people tend to also develop gray hair all of a sudden. However, in most people, this is a slow process, and one's hair colour does not change overnight, as the legend says.
The colour of our hair is made by pigments produced by the melanin cells in the hair roots. Gray hairs are made because these cells disappear, and hence there are no pigments made. Therefore, the colour slowly disappears, starting from the roots.
Gray hair in young people is most likely due to genetic causes, but other conditions, such as vitiligo, and male-type baldness can also show gray hair during the recovery phases. Other genetic diseases can also cause gray hair. Decreased pigmentation of the hair can occur from medications, while inflammatory skin disease can also disrupt melanin cells, causing graying of the hair.
Those who develop gray hair earlier than usual are described as having early onset poliosis. This varies between ethnicities, but is often defined as gray hair before the 20s and 30s. Such early onset poliosis is generally genetically related, but can also be associated with hyperthyroidism, hypothyroidism, severe anaemia, diabetes and other autoimmune diseases. Therefore, the saying that if you think too much, you develop gray hair may make some sense if it is associated with stress. Psychological stress can disrupt blood flow and the supply of nutrients to the hair roots, or cause abnormal hormone production to cause a decrease in melanin pigments to cause gray hair. However, there are no certain statistical or scientific explanations for this.
There are other urban myths related to gray hair. Some of these include the common misconception that pulling out a gray hair will lead to two gray hairs. Gray hair starts from the sides of the head, and progresses to the top and back of the head. If you see gray hair below the ears, it is likely that poliosis has progressed.
Gray hair occurs in both men and women similarly, but they say that men develop gray hair earlier. On average, gray hair occurs in the early 30s in Caucasians, and progresses to half the head or the scalp by the 50s. Black people develop gray hair about 10 years later than Caucasians, generally in the early 40s. For Japanese people, the average is 30-34 in men and 35-39 in women. Removing gray hairs will not slow the process. This is because gray hair will re-grow in the same spot in 2-3 weeks.
There are no known treatments for gray hair. The best method available at the moment is dyeing it.