What are the leading causes of adult mental retardation? Possible causes in drop of IQ?

What're primary causes of retardation, IQ decrease, general stupidness?

Say a person started off very smart. Nature gives that person a lot of mental gift and brain power, what are some causes of retardation for adults? Could it be due to Chemcial inbalance? Substance abuse? Life style factors? Behavioral (OCD, masturbation, nervous habits, behavioral disorders)? Sex abuse? Mental illness? Physical illness? Stress? Depression? Toxins/poisons? Or what? What are signs to watch for for this mental challenges/changes in adults?

My joke answer is watching Anime. My real answer would probably still sound like a joke due to this question being ill-concieved. The mental effectiveness of a person varies, and no one will tell you that one thing causes a problem for all. It varies by person. One person could have had an accident, another it could be diet, or perhaps a disease. As far as signs are concerened it also depends what you are looking for. Mental dysfunction can be linked to memory loss or word association misshaps or many other things like not being able to draw a pine tree, (seriously there are studies that claim if only one side of a brain is working it can't interpret an entire picture). So....it depends!

A baseball bat to the head might have that effect.

Many of the things you sited could have mind altering changes on the brain. Drug and alcohol abuse definitely do not help one stay sharp.

As people get older the body starts to deteriorate so why not the mind also?

drug abuse has to be on that list of how to get stupid ,i dont think masterbation can cause drain bamage(hah hah)some people just stop trying to think challenges throo.there are thinkers and there are doo ers,doo ers dont want to think they just want to be told what to do ,thinkers dont want to be told what to do .i think a sign of mental challenge is that persons job/trade...librarian=thinker,constructi... laborer= doo er, teacher =thinker, cashier=doo er and so on.

I don't know if there's a leading cause, maybe Alzheimer, but it has to be any kind of brain damage.

My husband has frontotemporal dementia. This particular brand of dementia is due to the frontotemporal lobes atrophying, or shrinking, for unknown reasons.

Prior to this diagnosis, he was screened for Alzheimer's. After that, he was treated as though it were "Vascular Dementia", that perhaps there was blood pressure or diabetes or cholesterol issues that affected him.

Brain trauma can cause dementia.

Brain tumors can cause dementia.

Signs to watch for? This is hard to say because they can be so subtle. As soon as you suspect something, see a doctor, but remember:

It is normal to forget where your car keys are, it is not normal to forget what they are FOR.

It really can depend on your location...
I taught special education on an Indian Reservation and the primary cause of MR there was Fetal Alcohol Syndrome with some drug cases in there as well.

I've had other students who were essentially born "normal" and then have encountered years of physical/sexual abuse and are now functioning at an IQ lower than 70. So there can also be environmental causes.

Another cause is just "bad genes" from parents. Some parents are genetically pre-disposed to having offspring with MR and chromosomal deviations run in the family.

Behavioral disorders do not cause MR, but can be a result of it. Mental illness and Mental Retardation are two different things. Mental Illness can be medically controlled...MR is permanent and manifests itself before the age of 20.

This topic has always been interesting to me, but I have recently learned to put the causes and dianoses aside and get to know the person rather than the disability.