There are two forms of treatment:
Organic methods, in this case
medication, are those that affect the body directly.
The four main classes of drugs are:
TCAs, MAOs and SSRIs are three classes of antidepressents with the most frequently prescribed being the TCAs. These need to be taken with a mood stabiliser (Lithium carbonate) as together will combat both the depression and mania.
Non organic methods are known as psychotherapy but are highly controversial and since the arrival of medication, have become disused.