Evaluation of the Effectiveness of a Psychoeducational Intervention in Treatment-Naïve Patients with Antidepressant Medication in Primary Care: A Randomized Controlled Trial

Table 3

Overall sample. Changes in BDI score within and between the intervention and usual care groups, with missing data replaced using the last value carried forward.

Sample	Months	Usual care group ()			Intervention group ()			Difference (95% CI) between groups (intervention group-usual care group)	value	SES^$
		Mean (SD)	Difference (95% CI)	SRM^#	Mean (SD)	Difference (95% CI)	SRM^#	Difference
Overall	Preintervention	19.07 (5.69)			20.14 (6.32)
	3 (postintervention)	18.29 (6.53)	0.78 (−0.53 to 2.10)	0.16	14.68 (7.21)	5.46 (3.52 to 7.40)	0.80	−3.61 (−6.25 to −0.95)	0.008	0.55
	6	16.86 (6.91)	2.21 (0.19 to 4.24)	0.29	15.16 (8.92)	4.98 (2.53 to 7.43)	0.57	−1.70 (−4.75 to 1.36)	0.273	0.25
	9	15.66 (7.22)	3.41 (1.37 to 5.45)	0.44	14.34 (8.59)	5.80 (3.60 to 8.00)	0.75	−1.32 (−4.36 to 1.72)	0.392	0.18

Abbreviations: SD: standard deviation and CI: confidence interval.
Differences were calculated between the baseline measurement and the follow-up measurement.
Positive differences indicate improvement; negative ones denote some worsening in clinical measures.
^#SRM: standardized response mean, calculated as the mean change in score divided by the standard deviation of the change in score.
^$SES: standardized effect size was computed as the mean difference between the intervention and control groups divided by the standard deviation of the control measurement.
A positive SRM or SES denotes improvement; a negative one denotes some worsening in clinical measures.
The difference was calculated between the intervention group and the control group.
Negative differences indicate improvement in the intervention group; positive differences denote worsening in the intervention group.
Interpretation effect sizes: values of 0.2–0.5 represent small changes, 0.5–0.8 moderate changes, and >0.8 large changes.