Can untreated Hypothyroidism lead to permanent brain damage/dementia?

[Scarface94]

I was reading this website that said if Hypothyroidism is not treated early, it can cause permanent brain damage and permanent dementia. I am really worried now because I have had it since I was 15 and I'm 20 now, and I just found out about this disease so I'm going in on the 18th to get treated. Is 5 years a long enough time to cause permanent brain damage and dementia? My brain (memory, thinking, concentrating) is really bad right now, does that mean it's permanent?

Here is a line from the article: "An underactive thyroid can lead to progressive loss of interest and initiative, slowing of mental processes, poor memory for recent events, fading of the personality's colour and vivacity, general intellectual deterioration, depression with a paranoid flavour, and eventually, if not checked, to dementia and permanent harmful effects on the brain."

Here is a link to the article: http://www.thyroid.ca/e10f.php

[gimel]

Far worse than your experience.  As I said, no need to worry about it.  Just get your thyroid hormone levels optimized.  

[Red_Star]

I had severe hypothyroidism symptoms with severe bradypnea.  I had dementia symptoms from hypothyroidism but it was reversible.  I have holes in my memory but that would be due to vitamin B12 malabsorption. I don't recall events that you wouldn't be likely to forget. eg: my grandfather almost cut his finger off on christmas day and went to hospital apparently lol.

[Scarface94]

What would be considered very severe hypothyroid conditions?

[gimel]

It is unfortunate that the author of that article did not make any attempt to define what he meant by "an underactive thyroid", nor how long such a condition would have to exist before causing permanent harmful effects.  I expect that he is talking about very severe hypothyroid conditions for extended periods.  Otherwise there are lots of us that have been hypothyroid for many, many years before being adequately treated, that would be in big trouble.  I was hypothyroid and inadequately treated for probably 35 years, until I located this forum 6 years ago.  You are worrying needlessly.  

I find it very ironic that the authors of articles in that link, who are so concerned about the possible effects of hypothyroidism, are Canadian.  I say that because the pervasive influence of their National Health Service  results in a large percentage of hypothyroid patients in that country being improperly diagnosed and treated, because of the "Immaculate TSH Belief" and use of "Reference Range Endocrinology".  We hear from lots of those unhappy patients here on the Forum and have to explain how they are not being adequately tested and treated.