Utility of the PHQ-9 to identify major depressive disorder in adult patients in Spanish primary care centres

Table 2 PHQ-based prevalence and comorbidity

	Total sample of PHQ respondents (n = 260)		Subsample of PHQ and SCID-I respondents (n = 178)
	n	%	n	%
Somatoform disorder (SD)
SD (≤ 5)	141	54.2	94	52.8
Major depressive disorder (MDD)
MDD (Algorithm)	178	68.5	124	69.7
MDD (≤ 10)	203	78.1	138	77.5
Panic disorder (PD)
PD (Original Algorithm)^a	57	21.9	40	22.5
PD (Modified Algorithm)^b	110	42.3	74	41.6
General anxiety disorder (GAD)
GAD (≤ 10)	180	69.2	128	71.9
Eating disorder
(PHQ Algorithm)	45	17.3	30	16.9
Alcohol abuse
(PHQ Algorithm)	38	14.6	25	14.0
Comorbidity
MDD + GAD	150	57.7	107	60.1
MDD + SD	115	44.2	81	45.5
GAD + SD	117	45.0	81	45.5
MDD + GAD + SD	104	40.0	74	41.6
GAD + PD	45	17.3	33	18.5
MDD + PD	40	15.4	30	16.9
MDD + GAD + PD	37	14.2	29	16.3
PD + SD	42	16.2	27	15.2
SD + GAD + PD	36	13.8	25	14.0
MDD + SD + PD	34	13.1	23	12.9
SD + MDD + PD + GAD	32	12.3	22	12.4
SD + MDD + PD + GAD	1	0.4	1	0.3
+ Eating + Alcohol

Note: SD somatoform disorder, MDD major depressive disorder, PD panic disorder, GAD general anxiety disorder, Eating eating disorder, Alcohol alcohol abuse. Comorbidity categories are not exclusive (e.g., “MDD + GAD” comprises “MDD + GAD + SD”)
^aOriginal Algorithm: All of the first four questions are answered with “yes,” and presence of four or more somatic symptoms during an anxiety attack
^bModified Algorithm: At least two of the first four questions are answered with “yes,” other coding criteria unchanged. (See Muñoz-Navarro et al. for more details; [35])