Not one to the exclusion of other.

The spike can just as well be caused by bad environment we made for ourselves, ecologically and psychologically.

The problem is, we really do not know what we're doing when dealing with mental issues. Typical western approach is only slightly better than dosing people with random psychedelic substances of mostly unknown effects. The science done in field of psychotherapy is low to non-existent quality. Methodologies are in their infancy.

Of course something barely effective will fail.