Frequent nightmares in Chinese patients undergoing methadone maintenance therapy: prevalence, correlates, and their association with functional impairment

Figures & data

Table 1 Characteristics of the sample of Chinese methadone-maintained heroin-dependent patients, and prevalence rates of frequent nightmares according to variables

Variables		n	Nightmares
			Number	%	χ2	P
Gender	Male	412	98	23.8
	Female	191	58	30.4	2.397	0.122
Age (years)^a	≤39	327	83	25.4
	≥40	276	73	26.4	0.143	0.705
Education	Junior high school and below	373	78	20.9
	Senior high school and above	230	78	33.9	11.603	0.001
Marital status^b	Married	295	69	23.4
	Non-married	308	87	28.2	2.081	0.149
Employment	Yes	317	67	21.1
	No	286	89	31.1	6.79	0.009
Self-rated economic status	Good	149	35	23.5
	Fair	314	83	26.4
	Poor	140	38	27.1	0.884	0.643
History of re-education through forced labor^c	Yes	286	87	30.4
	No	317	69	21.8	5.87	0.015
Route of past heroin administration	Smoking	96	12	12.5
	Injecting	507	144	28.4	12.851	<0.001
Duration of heroin use (years)^a	≤10	373	90	24.1
	>10	230	63	27.4	0.802	0.37
Duration of MMT (months)^a	≤24	240	68	28.3
	>24	363	65	17.9	1.671	0.196
Methadone dose (md/day)^a	≤70	273	51	18.7
	>70	330	108	32.7	14.893	<0.001
Current drinking	No	507	133	26.2
	Yes	96	23	24	0.218	0.641
Current smoking	No	51	24	47.1
	Yes	552	132	23.9	13.042	<0.001
Currently taking hypnotics	No	504	111	22
	Yes	99	45	45.5	17.035	<0.001
Hepatitis B virus surface antigen	Positive	137	61	44.5
	Negative	466	95	20.4	32.169	<0.001
Hepatitis B virus core antibody	Positive	124	62	50
	Negative	479	94	19.6	47.391	<0.001
Hepatitis C virus antibody	Positive	471	139	29.5
	Negative	132	17	12.9	9.493	0.002
Pain	No	280	49	17.5
	Yes	323	107	33.1	18.006	<0.001
Depressive symptoms	No	399	81	20.3
	Yes	204	75	36.8	15.102	<0.001
Anxiety symptom	No	384	76	19.8
	Yes	219	80	36.5	16.188	<0.001
Insomnia	No	230	31	13.5
	Yes	373	125	33.5	28.197	<0.001

Notes: ^aContinuous variables were dichotomized at the median. ^b“Non-married” includes never-married, remarried, cohabitating, separated/divorced, and widowed. ^cAn old model of heroin detoxification in China, which was officially abolished in 2013. It refers to administrative detentions for persons with heroin addiction who relapse or inject heroin after compulsory detoxification.

Table 2 Results of multiple logistic regression analysis on factors significantly associated with frequent nightmares in Chinese methadone-maintained heroin-dependent patients

Variables	Risk level	Reference level	Coefficient	Standard error	Wald χ2	P	OR (95%CI)
Education	Senior high school and above	Junior high school and below	1.005	0.262	14.729	<0.001	2.73(1.64,4.56)
Employment	No	Yes	1.151	0.269	18.287	<0.001	3.16(1.87,5.36)
History of re-education through forced labor	Yes	No	1.144	0.266	18.452	<0.001	3.14(1.86,5.29)
Route of past heroin administration	Injecting	Smoking	1.286	0.422	9.271	0.002	3.62(1.20,8.26)
Methadone dose (md/day)	>70	≤70	0.707	0.256	7.625	0.006	2.03(1.23,3.35)
Hypnotic use	Yes	No	0.647	0.322	4.046	0.044	1.91(1.02,3.59)
Hepatitis B virus core antibody	Positive	Negative	1.53	0.419	13.35	<0.001	4.63(2.03,10.53)
Pain	Yes	No	1.162	0.309	14.143	<0.001	3.20(1.74,5.86)
Anxiety symptom	Yes	No	0.637	0.302	4.449	0.039	2.06(1.04,4.48)
Insomnia	Yes	No	1.748	0.318	30.21	<0.001	5.75(3.08,10.72)

Table 3 Results of multiple linear regression analysis on the relationship between frequent nightmares and functional impairment, as measured by Sheehan Disability Scale

Control variables	Coefficient	Standard error	t	P
Model 1: only one predictor, nightmares	3.153	0.790	3.99	<0.001
Model 2: controlling for socio-demographic variables	2.946	0.863	3.414	<0.001
Model 3: controlling for socio-demographic and drug use related variables	2.747	1.063	2.583	0.009
Model 4: controlling for socio-demographic variables, drug use characteristics, and physical health	2.837	1.026	2.765	0.006
Model 5: controlling for socio-demographic variables, drug use characteristics, physical health, and mental health	2.528	0.971	2.604	0.009
Model 6: controlling for socio-demographic variables, drug use characteristics, physical health, mental health, and insomnia	2.718	0.978	2.778	0.006