Some mental disorders are directly attributable to brain abnormalities (not damage, exactly, but, yes, a human brain damaged as a result of an automobile wreck can cause mental disorders) and it’s likely that neurological abnormalities will, in the future, be found to be the cause of mental illnesses.

I’m sure that some medications can cause damage to the brain but I don’t know of any offhand. Medications can alter brain functions.

I don’t think that you need to worry.