Table 3.

Medication purchases by type of antidepressant medication for one month or more, by treatment resistant depression, for the incident study cohort (patients with the start of any major depressive disorder episode within the study period, 1/1/2016–31/5/2018), n = 2553

		Patients without TRD (N = 1929, 75.6%)		Patients with TRD (N = 624, 24.4%)		Total (N = 2553)
		N	%	N	%	N	%
SSRI monotherapy	Single purchase	163	17.9%	75	28.0%	238	20.2%
	> 1 purchase	748	82.1%	193	72.0%	941	79.8%
	Total	911	100.0%	268	100.0%	1179	100.0%
Other monotherapy	Single purchase	133	23.2%	37	20.9%	170	22.7%
	> 1 purchase	440	76.8%	140	79.1%	580	77.3%
	Total	573	100.0%	177	100.0%	750	100.0%
Combination therapy	Single purchase	21	5.3%	6	3.8%	27	4.9%
	> 1 purchase	372	94.7%	150	96.2%	522	95.1%
	Total	393	100.0%	156	100.0%	549	100.0%
TCA monotherapy	Single purchase	22	42.3%	6	26.1%	28	37.3%
	> 1 purchase	30	57.7%	17	73.9%	47	62.7%
	Total	52	100.0%	23	100.0%	75	100.0%
Total	Single purchase	339	17.6%	124	19.9%	463	18.1%
	> 1 purchase	1590	82.4%	500	80.1%	2090	81.9%
	Total	1929	100.0%	624	100.0%	2553	100.0%

(Other monotherapy comprised: 39.1% venlafaxine, 21.5% duloxetine, 10.1% vortioxetine, 9.2% bupropion, 8.4% mirtazapine, 3.9% milnacipran)

TRD treatment resistant depression, TCA tricyclic antidepressants, SSRI selective serotonin reuptake inhibitors