Well, you could report the case to CPS and they may wish to take jurisdiction. As it were, I am an adoption and family law attorney. I have a client who has been looking to adopt a baby. If you would like to discuss that issue with me, you may contact my office at (951) 686-1010 or FamilyLawCalifornia@yahoo.com
I agree, you may want to get CPS involved. As far as the chemical imbalance, it is hard to determine whether the drugs are causing the issue, or if she is self-medicating. You don't have to wait until the baby is born to take action. If nobody intervenes before the baby is born, the hospital may test the baby for drugs if made aware of the situation. Once they are aware that the baby has drugs in its system, they will contact authorities.
Since legal advice must be tailored to the specific circumstances of each case, and laws are constantly changing, nothing provided herein should be used as a substitute for the advice of competent legal counsel.