The minimal level of training for practitioners in mental health is a master’s degree in psychology. Weekend courses and training camps are called “continuing education” for those of us who hold professional degrees and licenses, and do not constitute professional training in and of themselves. Beware of those who pump themselves up with meaningless letters after their names. “Ph.D. or Psy.D.” (doctor) and “M.A. or M.S.” (master’s degree) are the letters you are looking for. The rest is fluff.
For yours and your child’s protection, be sure that the person holds a license through the California Board of Psychology(doctors) or the California Board of Behavioral Sciences (all others). Mental health licenses in the state of CA are the following: Licensed Clinical Psychologist (doctors licensed by the Board of Psychology), and all others who are licensed by the BBS —educational psychologist (LEP), social workers (LCSW), marriage and family therapists (MFT).
You should make sure that the person holds a master’s degree or doctorate in psychology, and that the main emphasis of their formal training was with children and adolescents.
If you wish to obtain a diagnosis, choose a doctor (licensed psychologist). Even if subdoctoral-level specialists claim to “diagnose,” be aware that most governmental agencies won’t accept the “diagnosis” from sub-doctoral level practitioners (e.g. licensed educational psychologists, school psychologists, MFTs, etc.). There are now even speech-language people with master’s degrees who sometimes pretend that they are capable of giving a DSM diagnosis. When in doubt, ask “would a diagnosis from you stand up in a court of law?”