What are the ways someone can become mentally disabled other than being born that way or an accident?

Drug overdose--when the patient suffered a loss of oxygen to the brain before or during resuscitation.

Senile Dementia--either early or late-onset.

The human version of "mad cow" disease (and other versions of Transmissible spongiform encephalopathy

That's all I can think of now.

Family. Just imagine a little baby growing up in an abusive household (sexual or physical abuse) or one where the parents send out powerful mixed signals (a father who calls his son weak, but beats his son up when he stands up to father; a mother who blames the child for all that's wrong in her life; a father who is a cold and delivers strict rules to his children; etc.). In fact, that's one the most common ways that people grow up with serious mental disorders. Or imagine a kid who given from foster family to foster family, and grows up without ever having a role model of what love is. When this thing happens to little kid, it can really screw them up. That's why good parenting is so important.

I kno that you can get cebral palsey from a lack of breathing while the baby is still in the mommy

Long term drug or alcohol abuse kills brain cells, which would result in mental disability (eventually).

I know years of bulimia wreaked havoc on my brain chemistry.

doing drugs

Drug overdose or incorrect medication.

Substance abuse