The combined federal drug control budget request for Fiscal Year 2018 is $27.57 billion, up from $23.8 billion in 2013.

Table: Federal Drug Control Spending by Function FY2013 through FY2018 as estimated by the Office of National Drug Control Policy.

ONDCP changed its method of accounting for treatment spending in its FY2018 report. According to footnote two for table two, p. 18, in the FY2018 budget report: "The estimates for the CMS [Centers or Medicare and Medicaid Services] reflect Medicaid and Medicare benefit outlays (excluding spending under Medicare Part D) for substance use disorder treatment; they do not reflect budget authority. The methodology for Medicaid estimates has been refined from prior years to more accurately reflect spending. The estimates were developed by the CMS Office of the Actuary." Questions have arisen regarding this decision, so in order to provide a better understanding of these figures, here's a Table of Federal Drug Control Spending by Function FY2008 through FY2016 and the request for FY2017 as estimated by ONDCP in December 2016.

The FY2017 budget report from ONDCP, which was issued in early January 2017, showed the following final figures for FY2015:
Treatment: $12.54 billion (43.4% of total)
Prevention: $1.34 billion (4.6% of total)
Domestic Law Enforcement: $9.4 billion (32.5% of total)
Interdiction: $3.96 billion (13.7% of total)
International: $1.64 billion (5.7% of total)
Total: $28.88 billion

The FY2018 budget report from ONDCP, which was issued in May 2017, shows the following final figures for FY2015:
Treatment: $9.55 billion (36.9% of total)
Prevention: $1.34 billion (5.2% of total)
Domestic Law Enforcement: $9.4 billion (36.3% of total)
Interdiction: $3.96 billion (15.3% of total)
International: $1.64 billion (6.3% of total)
Total: $25.89 billion

FY2016 figures were also adjusted:
According to the FY2017 Budget Report
2016 Enacted:
Treatment: $13.25 billion (43.4%)
Prevention: $1.5 billion (4.9%)
Domestic Law Enforcement: $9.7 billion (31.7%)
Interdiction: $4.48 billion (14.7%)
International: $1.64 billion (5.4%)
Total: $30.56 billion

However according to the FY2018 report:
FY2016 Final:
Treatment: $9.85 billion (36.6% of total)
Prevention: $1.49 billion (5.5% of total)
Domestic Law Enforcement: $9.28 billion (34.5% of total)
Interdiction: $4.73 billion (17.6% of total)
International: $1.52 billion (5.7% of total)
Total: $26.87 billion