The effect of knowledge and expectations on adherence to and persistence with antidepressants

Figures & data

Figure 1 Participant flowchart.

Table 1 Participant characteristics

Parameter	Number (%) of participants (N=220)
Median age in years (range)	23 (18–71)
Sex
Male	50 (22.7)
Female	170 (77.3)
Participants still on an antidepressant	182 (82.7)
Have continued original antidepressant	166 (75.5)
Have switched antidepressants	16 (7.3)
Time since starting antidepressant
0–1 months	30 (13.6)
1–3 months	46 (20.9)
3–6 months	106 (48.2)
Adherence for those still taking an antidepressanta
Adherent	141 (77.9)
Not adherent	40 (22.1)
Participants not taking an antidepressant	38 (17.3)
Never started the prescribed antidepressant	7 (3.2)
Have stopped the antidepressant	31 (14.1)
Duration of treatment before antidepressant was stopped
0–1 months	5 (2.3)
1–3 months	15 (6.8)
3–6 months	11 (5.0)

Notes: N= total number of participants analyzed.

a One participant chose not to answer this question.

Table 2 Reasons given for switching, stopping, or never starting the prescribed antidepressant

Reasona	Switched, n (%) (n=16)	Stopped, n (%) (n=31)	Never started, n (%) (n=7)
I was worried about possible adverse effects	1 (6.25)	1 (3.2)	4 (57.7)
I experienced adverse effect(s)	7 (43.8)	11 (35.5)	–
I didn’t think I needed to be on an antidepressant	–	1 (3.2)	4 (57.7)
I felt better	–	5 (16.1)	1 (14.3)
It wasn’t working for me	12 (75)	15 (48.4)	–
I was worried about becoming too dependent on it	–	6 (19.4)	2 (28.6)
Other	2 (12.5)	6 (19.4)	–

Notes: n= number of participants.

a Participants could select more than one reason, so percentages do not add up to 100%.

Table 3 Predictors of persistence

Parameter	Univariate analysis				Multivariate analysis
	All participants analyzeda (n=142)	Persistent (n=117)b	Nonpersistent (n=25)b	P-value*	Odds ratio	95% confidence interval		P-value*
						Lower	Upper
Median age in years (range)		23 (18–71)	22 (18–61)	0.076	1.0	1.0	1.1	0.205
Expectation score (±SD)		11.5 (±3.6)	7.4 (±4.1)	<0.001	1.2	1.0	1.4	0.100
Educational message received, n (%)
How the medication works	109 (76.8)	95 (84.8)	14 (60.9)	0.018	1.8	0.4	8.9	0.474
Told how long it should take to start having a noticeable effect and told a couple of weeks or a month or so	113 (79.6)	99 (86.8)	14 (58.3)	0.003	3.5	0.4	35.0	0.282
Don’t stop without checking with your doctorc	104 (73.2)	95 (82.6)	9 (40.9)	<0.001	5.9	1.4	24.5	0.014
Common adverse effects	113 (79.6)	97 (85.1)	16 (64.0)	0.030	0.3	0.02	3.2	0.273
How to manage minor side effects	66 (46.5)	60 (54.5)	6 (26.1)	0.024	0.6	0.1	3.2	0.528
What to do if experience major side effects	87 (61.3)	76 (67.9)	11 (45.8)	0.071	1.3	0.2	7.1	0.776
When or how long might have side effects	67 (47.2)	60 (55.0)	7 (29.2)	0.038	1.7	0.3	11.4	0.573
What to do if have questions about the use of the medicine	100 (70.4)	88 (78.6)	12 (50.0)	0.009	2.7	0.4	17.3	0.288

Notes: n= number of participants.

a Participants analyzed included those who had taken their antidepressant for at least 3 months (n=117) and those who had stopped after <3 months who did so without consulting their doctor (n=25).

b Some percentages may be out of a smaller denominator due to missing responses.

c Significant independent predictor.

* P<0.05 is considered significant.

Table 4 Predictors of adherence

Parameter	Univariate analysis				Multivariate analysis
	All participants analyzeda (n=181)	Adherent (n=141)b	Nonadherent (n=40)b	P-value*	Odds ratio	95% confidence interval		P-value*
						Lower	Upper
Median age in years (range)c		28 (18–71)	21 (18–57)	0.002	1.1	1.0	1.2	0.002
Expectation score (±SD)		11.9 (±3.6)	10.1 (±3.9)	0.006	1.1	1.0	1.2	0.169
Knowledge score (±SD)c		5.2 (±1.5)	4.7 (±1.6)	0.042	1.6	1.1	2.3	0.010
Educational message received, n (%)
How the medication works	147 (81.2)	119 (88.8)	28 (71.8)	0.018	2.5	0.7	9.5	0.181
Asked about prior use of a similar medicine	129 (71.3)	106 (77.4)	23 (60.5)	0.060	1.0	0.3	3.6	0.949
Common side effectsc	143 (79.0)	119 (85.6)	24 (61.5)	0.002	5.5	1.1	29.0	0.044
How to manage minor side effects	92 (50.8)	79 (58.1)	13 (36.1)	0.031	0.4	0.1	1.5	0.180
What to do if experience major side effects	116 (64.1)	98 (72.1)	18 (46.2)	0.005	1.4	0.3	5.4	0.669
Discussed things already doing that are helping	97 (53.6)	81 (59.1)	16 (40.0)	0.050	0.9	0.3	2.6	0.781
Discussed planning pleasurable activities	82 (45.3)	69 (50.4)	13 (32.5)	0.070	1.4	0.4	4.5	0.590
Discussed ways of solving problems having in lifec	82 (45.3)	71 (51.8)	11 (27.5)	0.011	3.9	1.1	14.5	0.042
Discussed identifying and changing thoughts that get you down	68 (37.6)	58 (42.3)	10 (25.0)	0.072	0.5	0.1	2.0	0.361

Notes: n= number of participants.

a Participants currently taking an antidepressant who had answered the questions pertaining to adherence were included in these analyses.

b Some percentages may be out of a smaller denominator due to missing responses.

c Significant independent predictor.

* P<0.05 is considered significant.