Here's what I found on a site I use for work sometimes.

The U.S. Food and Drug Administration approved Zeneca's Seroquel (R) (quetiapine fumarate) tablets, an oral medication indicated for the management of the manifestations of psychotic disorders, including schizophrenia. Seroquel was shown to be effective in treating both the positive symptoms (i.e., hallucinations, delusions) and negative symptoms (i.e., emotional withdrawal, blunted affect) associated with schizophrenia.

I also found a page for a clinical trial that's using it for dysphoric hypomania and depression.