The first question I have is when did you sign the most recent lease and what is the term for the lease? Certainly if you signed the lease with knowledge of the medical conditions there is not going to be a very good argument that you should be able to get out of the lease. Also, normally to break a lease due to health the leased property needs to be a danger to the tenant's health or safety.
This does not mean that you cannot break your lease, it may simply cause you to be responsible for any fees and costs associated with terminating your lease early. Also, this does not mean that you cannot negotiate a resolution with your landlord that is agreeable to both of you. Depending on your lease situation (what you are paying versus what the landlord might be able to get from a new tenant) you may be able to convince the landlord to let you leave without penalty. Also check to see if your lease allows you to sublect the premises (many do not) and if you are allowed the sublease the premises you can find someone else to stay in the property and you can move somewhere else. Even if you sublet the premises you are responsible for paying the landlord even if your sublet tenant does not pay you (be careful).
This information is provided for general informational purposes and is not intended as legal advice. An attorney licensed in your jurisdiction can answer questions specific to your specific fact situation and provide you appropriate advice as necessary based on the specific facts of your matter and the jurisdiction in which you reside. If you are in Arizona and interested in discussing your matter further I can be reached at: (480) 838-9000 Mark D. Fullerton, P.C. 1839 S. Alma School Road, Suite 275 Mesa, Arizona 85210