I suggest you email Charles Dean for his reference list. There have been some interesting associations between high DHEA levels and pychosis, but I haven't come across any studies where they actually gave young people high doses of the stuff and observed psychosis developing. It may be that Dean has been to some recent conferences where as-yet unpublished work was presented.
As far back as 1992:
Integr Physiol Behav Sci 1992 Jul-Sep;27(3):209-15
Severe psychosis and the adrenal androgens.
Howard JS 3rd.
Dept. of Health, Fresno, CA 93775.
Past literature suggests a link between certain psychotic states and adrenal androgen production, including Dehydroepiandrosterone (DHEA). A group of severely psychotic androgenized females, refractory to substantial amounts of neuroleptics, has been identified for whom endocrine testing revealed abnormally high levels of DHEA. A similar group has been identified among the severely psychotic male population. Improvement in psychosis appears to occur as DHEA returns to its normal range using standard low dose Dexamethasone suppression.
Without any hard clinical studies, the best advice for little girl would be to knock off the DHEA (for a variety of reasons) and see if her mood returns to normal. Chances are that her problem will be from the Primo, PCOS, or other endocrine imbalance/stress. But why take something that you don't need and is prolly not beneficial if there is even a slight chance of negative side effects??