Table 2.

Prevalence of CNS Medication Use and Dose Information Over Time^*

CNS Medication Use	Year 1 (N = 3,055), %	Year 2 (N = 2,911), %	Year 3 (N = 2,693), %	Year 5 (N = 2,480), %
Use of 2+ agents	2.98	3.85	4.34	4.29
Use of 1 agent	10.90	10.55	11.96	13.74
High-dose use (>3 SDD)	2.39	2.85	3.04	3.43
Medium-dose use (1–3 SDD)	3.50	4.19	5.76	6.33
Low-dose use (<1.0 SDD)	7.99	7.46	7.50	8.27
Long-term use	7.79	10.07	11.33	11.33
Short-term use	6.09	4.43	4.98	6.69

Notes CNS = central nervous system; SDD = summated standard daily dose.

^*Test of trend using GENMOD in SAS; χ² = 21.12, df = 1; p < .001.