Table 2.

Peer-reviewed studies of comorbidities

Authors	Year/ Country	Design	Data source	Sample/ Age in year	Substance	Selected findings
Lofwall et al.33	2005/USA	Cross-sectional	Year not available	n = 41; 50–66 years	Opioid-dependent patients	Lifetime disorder among patients aged 50–66 yrs (n = 41): major depression, 34.1%; alcohol, 75.6%; cocaine, 73.2%; opioid, 100%; cannabis, 41.5%; sedative, 36.6%.
				n = 26; 25-34 years
Merrick et al.29	2008/USA	Cross-sectional	2003 MCBS	n = 12413; ≥65 years	Alcohol	Prevalences of unhealthy drinking (men (16%), women (4%)): 65–70 years (13.0%), 71–80 years (8.7%), 81+ years (4.9%) Depressive symptoms were positively associated with unhealthy drinking.
Préville et al.28	2008/Canada	Cross-sectional	2005–2006 ESA	n = 2798; ≥65 years	Benzodia-zepine	Among persons with past-year benzodiazepine dependence (n = 64), 31.3% had 1-year mood or anxiety disorders
Rosen et al.34	2008/USA	Cross-sectional	Year not available	n = 140; ≥50 years	Opioid-dependent patients	Past-year prevalence: major depression, 32.9%; generalized anxiety disorder, 29.7%; PTSD, 27.8%; mood or anxiety disorder, 47.1%, arthritis, 54.3%; hepatitis C, 49.3%; hypertension, 44.9%; heart condition, 17.9%; lung disease, 22.1%; cirrhosis, 14.3%; diabetes, 11.4%
Sacco et al.31	2009/USA	Cross-sectional	2000–2001 NESARC	n = 4646; ≥60 years	Alcohol	Three groups from latent class analysis of alcohol users: low-risk, 89.2%; moderate-risk, 9.7%; high-risk, 1.2%. Comorbid disorder in each of the 3 groups: 1-year major depression (3.2%, 3.2%, 24.9%, respectively); 1-year anxiety disorder (1.4%, 2.3%, 8.8%, respectively); antisocial personality disorder (0.9%, 1.2%, 5.9%, respectively)
Blazer & Wu20	2009/USA	Cross-sectional	2005–2006 NSDUH	n = 10953; ≥50 years	Alcohol, Drugs	Major depression was associated with marijuana use and with cocaine use
Voyer et al.14	2009/Canada	Cross-sectional	2005–2006 ESA	n = 2785; ≥65 years	Benzodia-zepine	Mild cognitive impairment, major depression, anxiety disorder and suicidal ideation were associated with increased odds of benzodiazepine dependence
Woo & Chen35	2010/USA	Cross-sectional	2006–2007	n = 90; ≥65 years	Drugs	Prevalence of drug use among psychiatric emergency patients from urine toxicology screens: amphetamines (8.9%), benzodiazepines (6.7%), cocaine (6.7%), opiates (3.3%), barbiturates (1.1%)
Pietrzak et al.32	2011/USA	Cross-sectional	2004–2005 NESARC	n = 9,463; ≥60 years	Drugs	PTSD was associated with lifetime mood, anxiety, drug use and borderline and narcissistic personality disorders
Choi & Dinitto30	2011/USA	Cross-sectional	2005–2006 NSHAP	n = 2924; ≥57 years	Alcohol	The number of depressive symptoms was positively associated with binge/heavy alcohol use in men only
Chou et al.15	2011/USA	Longitu-dinal	2000–2001 & 2004–2005 NESARC	n = 8012; ≥60 years	Alcohol, Drugs	3-year incidence of major depression: 3.5% in persons with alcohol abuse; 3.7% in persons with alcohol dependence; 6.7% in persons with a drug use disorder 3-year incidence of generalized anxiety disorder: 1.9% in persons with alcohol abuse; 1.6% in persons with alcohol dependence; estimates are not available for persons with a drug use disorder
Cicero et al.36	2012/USA	Cross-sectional	2008–2010	n = 2573; ≥18 years	Opioid-dependent patients	Opioid-dependent patients ages 45+ (n = 476) were more likely than younger opioid-dependent patients ages 18-44 years to have an anxiety/depressive disorder or alcohol dependence, and to report moderate-to-severe pain

ESA, Enquête sur la Santé des Aînés or Quebec Survey on the Health of Seniors; MCBS, Access to Care file of the Medicare Current Beneficiary Survey; NESARC, National Epidemiologic Survey on Alcohol and Related Conditions; NSDUH, National Survey on Drug Use and Health; NSHAP, National Social Life, Health, and Aging Project; PTSD, post-traumatic stress disorder.