Manual: In a manual transmission, the problem is not so much the fluid degradation, but rather fluid contamination. This contamination occurs over time as the synchronizers, bearings and gears in the transmission wear out. The resulting metal particles then float around in the lubricant.
A lot of mental illnesses can have a genetic component, yes (eg. depression, bipolar disorder, anxiety, antisocial personality disorder, etc.).
1 Here are some important facts about mental illness and recovery: 2  Mental illnesses are biologically-based brain disorders. 3  They cannot be overcome through will power and are not related to a person's character or intelligence. 4  Mental disorders fall along a continuum of severity.