Yes it seems a consensus was reached stating that, every single person, meaning all genes, carry embedded within them, the potential to manifest "mental illness" (typically Personality Disorders), however what determines these genes active is always Environment, and its many facets.
Therefore mental disorders are passed down through the generations, and then morph to suit whatever environmental factors it encounters. If this is correct it would mean with good parenting, like Stef advocates, which is no easy task, dysfunctional families and mental disorders can be corrected with one generation.
I think this theory probably holds some weight, clearly genes are affected by environment, and we as human beings can latch onto that, safely knowing, that if we change the environment for the better, the organism benefits.