Provided herein are methods of determining a treatment regimen for a subject with a mood disorder and methods of identifying a patient with a mood disorder as amenable to treatment with a calcium channel blocker (CCB). In exemplary embodiments, the methods comprise (a) analyzing a sample obtained from a subject with a mood disorder for the presence of allele [A] of CACNA1C, wherein allele [A] comprises the sequence of the polymorphic marker rs1006737.
