Ok, time I chimed in.... 25+ years as a licensed cosmetologist/hairdresser here (retired...oy, I'm too young for retirement) a few years back but still licensed to dish out suggestions and thoughts.
Ok, medication of any form (ie: heart meds, steroids as noted, etc) will have a direct affect on the chemical makeup of the hair shaft. Stress, diet, etc, also affects the hair. Think of it this way... the blood stream supplies the hair with it's nurishment, so anything in the blood will affect the chemical make up as well as stress.ÂÂ
So, how do we combat the frizzies?
Now, keep in mind there are many "moisturizing" conditioners out there. Now, not sure if you all know but.. if you over moisturize your hair, it will also cause the frizzies!  The hair shaft has a cuticle layer that is much like fish scales (acually, like the Schwann cells of our AN's as well!). Anyway, the moisture molecules of moisture shampoos and conditioners tuck themselves under these cuticile layers. If too much moisture molecules tuck under the cuticle layer, it will cause the frizzies.
Now, there are products such as serums and such that will help control the frizzies. There are some OTC products by FrizzEaze and Garnier that seem to work well. Remember to use just a VERY little bit...
Infusium is also a terrific product, which is a post-shampoo leave in conditioner, based on B-Complex, which is essential to hair.
FYI... any hair conditioner with B-complex is also great as a hand lotion.... I use them and it actually helps to strengthen my fingernails as well... which is also made up of B-complex.
So, there is a brief Cosmetology 101. Let me know on PM if you need any further help on this... I miss the days of doing hair and as you can see... it is in my blood!
Phyl