The impact of comorbid psychiatric disorders on methadone maintenance treatment in opioid use disorder: a prospective cohort study

Figures & data

Figure 1 GENOA study eligibility and screening of participants.

Note: ^aExcluded due to treatment with buprenorphine for substitute opioid therapy.
Abbreviation: GENOA, Genetics of Opioid Addiction.

Table 1 Characteristics of participants with and without psychiatric comorbidity receiving methadone treatment

Characteristics, N=652	Psychiatric comorbidity,a n=512	No psychiatric comorbidity, n=140	P-value
Current age (years), mean ± SD (range)	37.96±10.70 (18–65)	42.49±11.67 (21–64)	<0.001
Sex, n (% of subgroup)	M: 264 (51.56)	M: 89 (63.57)	0.012
	F: 248 (48.44)	F: 51 (36.43)
Highest completed education, n (% of subgroup)	None: 1 (0.20)	None: 0	0.357
	Elementary: 95 (18.63)	Elementary: 16 (11.59)
	Secondary: 271 (53.14)	Secondary: 85 (61.59)
	Trade school: 21 (4.12)	Trade school: 7 (5.07)
	College/university: 121 (23.73)	College/university: 30 (21.74)
	Masters/PhD: 1 (0.20)	Masters/PhD: 0
Unemployment, n (% of subgroup)	350 (68.36)	78 (55.71)	0.005
Using psychotropic medication,b n (% of subgroup)	249 (48.63)	51 (36.43)	0.010
Methadone dose (mg/d), mean ± SD (range)	77.12±45.84 (2–400)	78.67±48.39 (6–280)	0.726
Duration on MMT (months), mean ± SD (range)	50.18±50.87 (0.1–276)	52.70±46.22 (0.3–216)	0.597
Number of urine drug screens completed,c mean ± SD (range)	34.09±11.98 (7–76)	30.75±11.45 (2–74)	0.003
Percent opioid-positive urine drug screens,d mean ± SD (range)	18.93±27.42 (0–100)	17.00±27.18 (0–100)	0.460
Abstinence from illicit opioid use,e n (% of subgroup)	166 (32.42)	53 (37.86)	0.228

Notes:

a Psychiatric comorbidity in addition to OUD, as diagnosed by MINI, including major depression, bipolar affective disorder, anxiety disorder, psychotic disorder, eating disorder, antisocial personality disorder, substance use disorder and alcohol use disorder.

b Psychotropic medication taken in addition to methadone, including antidepressants, benzodiazepines, nonbenzodiazepine sedatives, antipsychotics, mood stabilizers, and stimulants.

c Number of urine drug screens completed over 6-month period, including 3 months prior to study entry and 3 months poststudy entry.

d Percentage of urine drug screens detecting illicit opioid use, taken over 6-month period, including 3 months prior to study entry and 3 months poststudy entry.

e Number of participants with zero opioid-positive urine drug screens completed over 6-month period, including 3 months prior to study entry and 3 months poststudy entry.

Abbreviations: F, female; M, male; MINI, Mini-International Neuropsychiatric Interview; MMT, methadone maintenance treatment; OUD, opioid use disorder; SD, standard deviation.

Table 2 Psychiatric comorbidity identified in participants receiving methadone treatmenta,b

Diagnosis	Number (% total study sample), N=652
Mood disorderc	270 (41.41)
Major depression	184 (28.22)
Bipolar affective disorder type I	73 (11.20)
Bipolar affective disorder type II	13 (1.99)
Anxiety disorderd	278 (42.64)
Generalized anxiety disorder	128 (19.63)
Social phobia	94 (14.42)
Posttraumatic stress disorder	71 (10.89)
Obsessive compulsive disorder	70 (10.74)
Panic disorder with agoraphobia	98 (15.03)
Panic disorder without agoraphobia	30 (4.60)
Co-occurring mood and anxiety disorders	150 (23.01)
Psychotic disordere	20 (3.07)
Schizophrenia	8 (1.23)
Schizoaffective disorder	0 (0)
Brief psychotic disorder	1 (0.15)
Delusional disorder	6 (0.92)
Substance-induced psychosis	4 (0.61)
Psychosis NOS	3 (0.46)
Eating disorderf	7 (1.07)
Anorexia nervosa	1 (0.17)
Bulimia nervosa	6 (1.15)
Antisocial personality disorder	146 (22.39)
Substance use disorderg	271 (41.56)
Stimulants	44 (6.75)
Cocaine	130 (19.94)
Hallucinogens	26 (3.99)
Phencyclidines	6 (0.92)
Inhalants	0 (0)
Cannabis	182 (27.91)
Tranquilizers	28 (4.29)
Other	3 (0.46)
Alcohol use disorderh	83 (12.73)

Notes:

a Psychiatric comorbidity as diagnosed by MINI.

b Percentages do not sum to 100% as some individuals are diagnosed with multiple comorbid disorders.

c Mood disorder includes major depressive episode, major depressive disorder, and bipolar affective disorder types I and II.

d Anxiety disorder includes generalized anxiety disorder, social phobia, posttraumatic stress disorder, obsessive compulsive disorder, and panic disorder with and without agoraphobia.

e Psychotic disorder includes schizophrenia, schizoaffective disorder, brief psychotic disorder, delusional disorder, substance-induced psychosis, and psychosis NOS.

f Eating disorder includes anorexia nervosa and bulimia nervosa.

g Substance use disorder includes substance abuse and substance dependence associated with use of the following substances: stimulants, cocaine, hallucinogens, phencyclidines, inhalants, cannabis, tranquilizers, and other.

h Alcohol use disorder includes alcohol abuse and alcohol dependence.

Abbreviations: MINI, Mini-International Neuropsychiatric Interview; NOS, not otherwise specified.

Table 3 Influence of psychiatric comorbidity on percentage of opioid-positive urine drug screens (N=652)

Covariates	Estimated β	95% CI	P-value
Current age (years)	0.173	−0.040, 0.385	0.111
Sex	−2.542	−6.803, 1.719	0.242
Methadone dose (mg/d)*	−0.074	−0.120, −0.028	0.002
Duration on MMT (months)	−0.035	−0.081, 0.011	0.139
Psychiatric comorbidity	3.069	−2.145, 8.282	0.248
Using psychotropic medication	−2.084	−6.398, 2.229	0.343

Notes: R²=0.026, adjusted R²=0.017.

* P<0.05.

Abbreviations: CI, confidence interval; MMT, methadone maintenance treatment.

Table 4 Influence of specific psychiatric comorbidities on percentage of opioid-positive urine drug screens (N=652)

Covariates	Estimated β	95% CI	P-value
Current age (years)	0.161	−0.049, 0.371	0.133
Sex	−1.533	−5.999, 2.933	0.500
Methadone dose (mg/d)*	−0.060	−0.107, −0.014	0.010
Duration on MMT (months)	−0.032	−0.077, 0.014	0.173
Mood disorder	−1.751	−6.144, 2.643	0.434
Anxiety disorder	−3.000	−7.426, 1.427	0.184
Psychotic disorder	−4.307	−16.483, 7.868	0.487
Antisocial personality disorder	0.977	−4.220, 6.175	0.712
Alcohol use disorder	0.303	−6.196, 6.802	0.927
Stimulant use disorder	−1.619	−10.531, 7.292	0.721
Cocaine use disorder*	6.344	0.592, 12.095	0.031
Hallucinogen use disorder	−4.528	−16.615, 7.560	0.462
Phencyclidine use disorder	14.194	−7.795, 36.184	0.205
Cannabis use disorder	−0.701	−5.857, 4.455	0.790
Tranquilizer use disorder***	20.781	10.006, 31.555	0.000
Other	10.146	−17.274, 37.567	0.468

Notes: R²=0.074, adjusted R²=0.05.

* P<0.05.

*** P<0.001.

Abbreviations: CI, confidence interval; MMT, methadone maintenance treatment.