Substance-Induced Versus Independent Depressions

A new study on substance-induced major depressive episodes (MDE) reaches a bold conclusion:

This study corroborates a high rate of substance-induced MDEs among alcoholics, with these disorders explaining about half of the lifetime depressive episodes.

Also worth noting, substance induced depressive episodes were no less severe:

...symptoms during the worst depressive episode were quite similar across [subjects with substance induced MDEs] and [subjects with independent MDEs].