This invention relates to compositions, methods for preparing the compositions and methods for treating or preventing diseases, comprising administering the compositions. A spin valve film has a stacked structure comprising a soft magnetic layer, a nonmagnetic layer, a ferromagnetic layer, an antiferromagnetic layer and a protective layer which are stacked in sequence on an underlying layer. The method targets the prevention of suicide, and provides other benefits including preventing disease progression development of tolerance toward the antidepressants.