Your diagnosis can be presented as mitigation in your case, but I would not expect that it would be a defense to your conduct. Since you have priors, you don't need me to tell you how important good legal representation is to you & your case. Once you've decided on who will represent you, have him / her review your facts, your diagnosis & treatment plan & your criminal history. You've been proactive in seeking treatment which can also be used to help you in resolving your case, assuming that the State has the ability to prove the charges. For more information on theft offenses, take a look at Florida Statute 812 or visit www.LadanLaw.com.
Amir A. Ladan
Posting an answer to your question does not create an attorney / client relationship such that you can or should rely on the information provided herein to take action. Instead, it is intended to simply provide you with information. I am not your lawyer and cannot provide you with legal advice unless and until I am hired to do so.
Do not give any more statements or evidence to the police. Hopefully, your employer is satisfied with getting their items back and is not advocating prosecution. However, the State could pursue charges regardless of your employer's wishes.
If you are arrested, don't say anything else and hire an attorney immediately. A good criminal defense attorney will first explore defenses to the charge. If you were to plea or be convicted, the fact that you were already getting help will be helpful for sentencing or plea negotiation.
You should not go to court without representation especially because of your priors. If you are called to court, however, plead not guilty and say nothing about the facts of your case. Then go talk to a lawyer. To answer the other part of your question, the diagnosis may help in discussing this matter with the State Attorney's Office. In fact, it may not hurt to hire an attorney now to do what can be done to try to prevent charges from being filed.