Oh everything effects my stutter - the biggest month to month change is my period. I can go from fluent to can't say my name just before my period. I think that's true of any disorder/difficulty. If you're struggling with mental illness, not taking care of yourself makes it worse. If you have a physical disability or chronic pain, it's worse when you don't take care of yourself. My son has a genetic disorder among a slew of diagnoses including a severe speech disorder (non-stutter), and everything is worse when we he eats poorly or has a bad night's sleep. I think it's pretty basic life truth.