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. Author manuscript; available in PMC: 2016 May 23.
Published in final edited form as: J Psychoactive Drugs. 2015 Jan-Mar;47(1):42–50. doi: 10.1080/02791072.2014.977501

The Prevalence of Posttraumatic Stress Disorder Symptoms among Addiction Treatment Patients with Cocaine Use Disorders

Elizabeth C Saunders a, Chantal Lambert-Harris b, Mark P McGovern c, Andrea Meier b, Haiyi Xie d
PMCID: PMC4876862  NIHMSID: NIHMS786611  PMID: 25715071

Abstract

Co-occurring cocaine use and posttraumatic stress disorders are prevalent and associated with negative treatment, health and societal consequences. This study examined the relationships among PTSD symptoms, gender, and cocaine use problems. Within a cross-sectional design, we gathered archival point prevalence data on new admissions (n = 573) to three addiction treatment agencies. Demographic, substance use, and PTSD symptom information were collected across the three agencies. Logistic regression analyses revealed that patients with cocaine use disorders had a two-fold increased odds for a probable PTSD diagnosis, compared to patients without a cocaine use disorder (OR = 2.19, 95% CI = 1.49–3.22, p < 0.001). Among females with cocaine use disorder, multinomial regression yielded a significant increase in the risk of moderate (RRR = 2.12, 95% CI = 1.10–4.10, p < 0.05) and severe (RRR = 2.87, 95% CI = 1.33–6.21, p < 0.01) PTSD symptoms. Males with cocaine use disorders had a two-fold increase in the risk of moderate PTSD symptoms (RRR = 2.13, 95% CI = 1.23–3.68, p < 0.01), but had no increased risk of developing severe PTSD symptoms (RRR = 1.93, 95% CI = 0.85–4.39, p = 0.117). Cocaine use appears to impact the risk of PTSD symptoms, especially in females. Future research should explore the generalizability of these findings to more racially and ethnically diverse samples, as well as among persons with this comorbidity who are not engaged in treatment services.

Keywords: cocaine use disorders, gender, posttraumatic stress disorder

Cocaine remains the third most prevalent drug abused in the United States. In 2012, 1.1 million individuals met criteria for cocaine abuse or dependence (SAMHSA 2013). Cocaine use is associated with a number of negative psychosocial and physical health consequences, including increased criminal involvement, social dysfunction, unemployment, and serious medical disease (Riezzo et al. 2012; Lange & Hillis 2001; Karila et al. 2012; Hser et al. 2006). Although more males than females use cocaine, females have higher rates of cocaine dependence and worse outcomes. These include more severe medical, family, employment, and mental health problems, such as mood and anxiety disorders (Chen et al. 2011; Najavits & Lester 2008; Stecker et al. 2007; Wu et al. 2010; Cotto et al. 2010; Griffin et al. 1989; Wong et al. 2002).

Research has found an association between co-occurring cocaine use and posttraumatic stress disorder (PTSD). The prevalence of current PTSD in cocaine users ranges from 8 to 43% (Back et al. 2000; Dansky, Brady & Saladin 1998; Ford et al. 2009; Najavits et al. 2003; Wasserman, Havassy & Boles 1997). A range of 23 to 42% of cocaine users have a lifetime PTSD diagnosis (Back et al. 2000; Halikas et al. 1994; Magura et al. 1998; Wasserman, Havassy & Boles 1997). Variation in prevalence estimates is due to methodological sampling and setting factors, including whether studies are conducted in community settings, residential programs, or in the Veteran’s Administration. Across studies, rates of PTSD are especially high in female cocaine users (Brady et al. 1998; Dansky, Byrne & Brady 1999; Falck et al. 2004; Halikas et al. 1994).

Several reports describe potential mechanisms for the relationship between PTSD and cocaine use. Witnessing or experiencing trauma while engaging in high-risk behaviors, such as obtaining, dealing, using or withdrawing from cocaine could contribute to the vulnerability to develop PTSD (Brady et al. 1998; Dansky et al. 1996). Both cocaine use and PTSD frequently co-occur with other Axis I disorders (Back et al. 2006; Najavits et al. 1998). Some researchers have hypothesized that patients may be using cocaine to manage these other negative symptoms, such as mood and anxiety problems (Bremner et al. 1996). While cocaine users may intend for the substance to ameliorate PTSD symptoms, cocaine use may increase hyperarousal and re-experiencing symptoms (Johnson et al. 2010; Tull et al. 2010). Comorbid PTSD and cocaine use disorders are associated with more severe substance use, higher rates of depression, greater interpersonal problems, and worse treatment outcomes than cocaine use problems only (Back et al. 2000; Clark et al. 2001; Hien et al. 2000; Najavits et al. 2003). In samples of treatment-seeking cocaine users, patients with PTSD were more likely to relapse during treatment, had shorter periods of abstinence, and were also less treatment-adherent than those without PTSD (Burns et al. 2010; Hien et al. 2000; Mancino 2010 et al. ; Najavits et al. 2007).

Poor treatment outcomes in patients with co-occurring PTSD and cocaine use disorders may be related to the relationship between substance use and PTSD symptoms. Despite great variation in the temporal onset of PTSD and cocaine use, studies have shown that PTSD symptom severity impacts cocaine use (Brady et al. 1998; Freeman, Collier & Parillo 2002; Johnson, Striley & Cottler 2006; Wasserman, Havassy & Boles 1997). In community and veteran samples, changes in substance use appear to parallel improvement or deterioration in PTSD symptom severity (Back et al. 2006; Bremner et al. 1996; Hien et al. 2010b). Similar trends are observed in studies of persons with cocaine dependence (Burns et al. 2010; Ouimette et al. 2010). Although these results imply an association between PTSD symptom severity and cocaine use, small sample sizes limit generalizability. Conversely, several studies have found that PTSD severity is unrelated to cocaine use (Ford et al. 2007; 2009). Other research has examined the reverse association and considered whether cocaine use symptoms are instead impacting PTSD symptoms (Back et al. 2006; Hien et al. 2010a).

These conflicting findings suggest that more research is needed to explore the relationship between cocaine use disorders and PTSD severity. No known studies have addressed whether gender differentially influences the relationship between cocaine use disorders and PTSD symptom severity. The aim of the current study is to investigate the prevalence of PTSD symptoms in community outpatients with cocaine use disorders, and to explore the relationship between cocaine use, gender, and PTSD symptom severity.

METHODS

Selection and Description of Study Participants

Within a prospective cross-sectional design, we examined the association between cocaine use disorders and PTSD symptoms in a treatment-seeking population. This sample was comprised of persons newly admitted to three outpatient community addiction treatment agencies during 2011. All new admissions were included, and there were no exclusion criteria. The agencies were located in northern, southern, and western Vermont, USA. Standardized archival chart reviews were completed for all admitted patients. The final sample included 573 patients.

Measures

PTSD symptoms were assessed using the PTSD Checklist-Civilian (PCL-C). The PCL-C is a 17-item, self-administered measure using a five-point Likert scale ranging from “Not at all = 1” to “Extremely bothered = 4.” After summing all responses, a total score of 44 or greater corresponds to a positive PTSD diagnosis (Blanchard et al. 1996; Terhakopian et al. 2008). Previous studies have shown that the PCL is highly accurate in predicting PTSD symptom severity among community samples (Blanchard et al. 1996; McDonald & Calhoun 2010). Numerous studies have used the PCL for this purpose (Blanchard et al. 1996; Grubaugh et al. 2007; Lang et al. 2003; Wilkins, Lang & Norman 2011). The reliability, validity, sensitivity, and specificity of the PCL have been validated in several studies, demonstrating that the PCL is a psychometrically sound self-report screening tool for PTSD and associated with a diagnosis of PTSD (Blanchard et al. 1996; Ruggiero et al. 2003; Weathers et al. 1993; 1994; McDonald & Calhoun 2010; Wilkins, Lang & Norman 2011).

Substance use problems and demographic information were extracted from patient medical records. Demographic information, including age, gender, race, and ethnicity, was collected by agencies mandated to adhere to the U.S. Substance Abuse and Mental Health Services Administration Treatment Episode Data Set (TEDS) federal reporting requirements. Primary, secondary, and tertiary substance use problems, which may include misuse, abuse, or dependence, were abstracted from the Addiction Severity Index (ASI; McLellan et al. 1985), a requirement of the state regulatory authority. The ASI is a well-established measure of substance use severity and also related to substance use diagnoses (McLellan et al. 1985; Rikoon et al. 2006; Leonhard et al. 2000; Currie et al. 2004; Alterman et al. 2000; McLellan et al. 1992).

Procedures

At admission, new patients completed the PTSD Checklist (PCL) and other standardized assessments. A program staff member at each site gathered information from medical records and linked this information with PCL scores. Data on patient demographics (age, gender, race, and ethnicity), PCL scores, and primary, secondary, and tertiary substance use problems were recorded, de-identified, and securely transferred to the research team. Because all data were de-identified, participant informed consent was not required. This study was conducted with approval from the Dartmouth College Committee for the Protection of Human Subjects (CPHS).

Data Analysis

Demographic, clinical, and substance use characteristics were examined using frequency analysis to calculate means, standard deviations and proportions. T-tests and Pearson’s chi-squared tests were used to compare group differences in demographic characteristics and PTSD diagnoses between cocaine users and non-users. PCL scores of 44 to 64 were considered moderate. Any PCL score of 65 and above was considered severe (Blanchard et al. 1996; McDonald & Calhoun 2010).

To determine whether cocaine use was associated with PTSD, logistic regression analysis was used to derive odds ratios and confidence intervals. The initial logistic regression model included the entire sample. Using a forward selection method, age, gender, race, and ethnicity were added to the original model as covariates, to control for confounding. Because of the racial and ethnic homogeneity of this sample, race and ethnicity were not included in the logistic models due to large standard error values. A second logistic regression model was used to derive odds ratios and confidence intervals, while controlling for other substance use. Age was centered before inclusion in analyses. To examine the association between gender, PTSD symptoms, and cocaine use, the odds of PTSD and the odds of cocaine use were calculated using logistic regression equations. Males were used as the referent group. Multinomial logistic regression analyses were conducted to investigate the influence of cocaine use and gender on PTSD symptom severity. Participants were then stratified by gender and analyzed in two separate multinomial regression analyses. Multinomial analyses controlled for age only. Data were analyzed using Stata 13 (StataCorp 2013).

RESULTS

Participant Demographics and Clinical Characteristics

The sample’s mean age was 34.64 years (Table 1). The majority of the sample were male, Caucasian, and not Hispanic or Latino. The mean PCL score was 41.10, and 42.4% of the sample met criteria for PTSD based on the PCL score cutoff (≥44). Of participants with probable PTSD, two-thirds met criteria for moderate PTSD severity, while close to one-third had severe PTSD symptoms. Cocaine was analyzed separately from other amphetamines because only three (1.9%) cocaine users also had other amphetamine use problems. Only two participants had cocaine use problems exclusively, and 157 patients had cocaine use problems in combination with other substances. These participants were combined to include all use of cocaine, either alone or in combination (n = 159; 27.7%). The most commonly used substances with cocaine were alcohol (n = 59), heroin (n = 44), and cannabis (n = 43).

TABLE 1.

Demographic and Clinical Characteristics of Adult Patients Newly Admitted to Community Outpatient Addiction Treatment Programs

Overall (n = 573) Males (n = 355) Females (n = 218) t/χ2 Valuea
Demographic characteristics
 Age, mean [sd] 34.64 [11.72] 35.53 [12.20] 33.19 [10.75] 2.33*
 Gender (% Female) 218 (38.0%) 355 (100%) 219 (100%)
 Race (% Caucasian/White) 541 (96.3%) 333 (95.4%) 208 (97.6%) 2.72
 Ethnicity (% Not Hispanic or Latino) 548 (98.9%) 339 (99.1%) 209 (98.6%) 0.35
PTSD symptom severity
 PCL score, mean [sd] 41.40 [17.66] 37.33 [16.60] 47.24 [17.65] −6.77***
 Probable PTSD diagnosis (% diagnosed) 243 (42.4%) 119 (33.5%) 124 (56.9%) 30.17***
 Moderate PTSD symptoms (% diagnosed) 168 (69.1%) 88 (73.9%) 80 (64.5%) 9.24**
 Severe PTSD symptoms (% diagnosed) 75 (30.9%) 31 (26.0%) 44 (35.5%) 32.86***
Type of substance use disorders
 Only Cocaine (%) 2 (0.4%) 1 (0.3%) 1 (0.5%) 0.12
 Cocaine + other substance(s) (%) 159 (27.8%) 86 (24.2%) 73 (33.5%) 5.78*
 Alcohol (%) 353 (61.6%) 249 (70.1%) 104 (47.7%) 28.74***
 Prescription opioid (%) 245 (42.8%) 130 (36.6%) 115 (52.7%) 14.36***
 Cannabis (%) 200 (34.9%) 134 (37.7%) 66 (30.3%) 3.32
 Heroin (%) 116 (20.2%) 60 (16.9%) 56 (25.7%) 6.46*
Co-occurring characteristics
 Cocaine + probable PTSD (%) 91 (15.9%) 40 (11.3%) 51 (23.4%) 14.87***
 Alcohol + probable PTSD (%) 138 (24.1%) 83 (23.4%) 55 (25.2%) 0.25
 Prescription opioid + probable PTSD (%) 116 (20.2%) 49 (13.8%) 67 (30.7%) 23.98***
 Heroin + probable PTSD (%) 54 (9.4%) 20 (5.6%) 34 (15.6%) 15.70***
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a

Differences between groups were tested as follows: means by t-tests, proportions by chi-squared tests.

*

p ≤ 0.05.

**

p ≤ 0.01.

***

p ≤ 0.001.

Association Between Cocaine Use and PTSD

Differences between participants with a cocaine use problem (n = 159) and participants without a cocaine use problem (n = 414) were compared using t-tests and chi-squared analyses (Table 2). Non-cocaine users were significantly older than cocaine users (p < 0.05). Alcohol, prescription narcotics, and heroin were the most common primary substance use problems for patients without cocaine use problems. Other amphetamine use problems were found in only four (<1%%) non-cocaine-using patients. Differences in probable PTSD diagnosis and severity were also seen between patients with and without cocaine use problems. Individuals with cocaine use problems were significantly more likely to meet criteria for a probable PTSD diagnosis. Additionally, a greater proportion of cocaine users met criteria for probable PTSD, compared to non-cocaine users.

TABLE 2.

Characteristics of Addiction Treatment Program Patients with Cocaine Use Disorders, Compared to Patients Without Cocaine Use Disorders

Characteristic Cocaine Use Disorder (n = 159) No Cocaine Use Disorder (n = 414) t/χ2 Valuea
Age, mean [sd] 32.96 [8.88] 35.28 [12.59] 2.13*
Gender, (% Female) 73 (45.9%) 145 (35.0%) 5.78*
Race, (% Caucasian/White) 144 (92.9%) 397 (97.5%) 17.70***
Ethnicity, (% Not Hispanic or Latino) 149 (97.4%) 399 (99.5%) 4.63*
PCL score, mean [sd] 46.17 [17.56] 39.16 [17.33] 4.32***
Probable PTSD diagnosis, (% diagnosed) 91 (57.2%) 152 (36.7%) 19.80***
PTSD severity, (%) 20.15***
Moderate PTSD symptoms 61 (38.4%) 107 (25.8%)
Severe PTSD symptoms 30 (18.9%) 45 (10.9%)
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a

Differences between groups were tested as follows: means by t-tests, proportions by chi-squared tests.

*

p ≤ 0.05.

**

p ≤ 0.01.

***

p ≤ 0.001.

Results of the first multivariate logistic model are reported in Table 3. After adjusting for age and gender, the odds of having PTSD were 2.19 times higher in patients with cocaine use disorders, than patients without cocaine use disorders. The relationship between PTSD symptoms and cocaine use disorders was strengthened after controlling for other substance use. Alcohol, heroin, cannabis, amphetamine, and prescription opioid use were added to the logistic regression model as dichotomous control variables. Prior to inclusion in this model, correlations between these variables were checked for collinearity. In this model, the odds of probable PTSD in patients with cocaine use was 2.26 times higher than in patients with no cocaine use. The odds of PTSD symptoms were 3.07 times higher in participants using cocaine and alcohol compared to participants using alcohol only, or alcohol and other drugs (95% CI = 1.68–5.44; p < 0.001). Results of the first multinomial logistic regression model, adjusted for age and gender, showed that the risk of moderate PTSD symptom severity was 2.11 times higher among patients with cocaine use disorders (95% CI = 1.38–3.21, p < 0.01), while the risk of severe PTSD symptom severity was 2.41 times higher (95% CI = 1.39–4.18, p < 0.01).

TABLE 3.

The Effect of Cocaine Use on PTSD Symptoms in Community Outpatients

Multivariate Logistic Model Odds Ratio (95% CI) p Value
Odds of probable PTSD diagnosis <0.001
Substance Use Disorders1
 No Cocaine Use Disorder 1.00 (reference)
 Cocaine Use Disorder 2.19 (1.49−3.22)
Age 1.00 (0.99−1.02) n.s.
Gender <0.001
 Male 1.00 (reference)
 Female 2.53 (1.78−3.61)
Odds of probable PTSD diagnosis <0.001
Substance Use Disorders2
 No Cocaine Use Disorder 1.00 (reference)
 Cocaine Use Disorder 2.26 (1.50−3.39)
Age 1.01 (0.99−1.03) n.s.
Gender <0.001
 Male 1.00 (reference)
 Female 2.56 (1.77−3.68)
Cannabis Use Disorder n.s.
 None 1.00 (reference)
 Cannabis Use Disorder 1.22 (0.83−1.79)
Alcohol Use Disorder n.s.
 None 1.00 (reference)
 Alcohol Use Disorder 1.19 (0.76−1.87)
Heroin Use Disorder n.s.
 None 1.00 (reference)
 Heroin Use Disorder 1.15 (0.72−1.83)
Prescription Opioid Use Disorder n.s.
 None 1.00 (reference)
 Prescription Opioid Use Disorder 1.33 (0.89−2.00)
Amphetamine Use Disorder n.s.
 None 1.00 (reference)
 Amphetamine Use Disorder 3.86 (0.67−22.36)
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1

Adjusted for age and gender.

2

Adjusted for age, gender, and other substance use (cannabis, amphetamine, heroin, prescription opioid, alcohol).

Influence of Gender on the Association Between PTSD Severity and Cocaine Use

This study found that gender confounded the relationship between cocaine use problems and PTSD symptoms. To further examine the relationship between gender, PTSD severity, and cocaine use, substance use and PTSD characteristics were examined in males and females using chi-squared analyses and t-tests (Table 1). Overall, a greater proportion of females had cocaine use problems. After adjusting for age, females had greater odds of having a cocaine use problem than males (OR = 1.54; 95% CI = 1.05–2.24; p<0.025). Females also had significantly higher PCL scores, and were more likely to be diagnosed with PTSD. Among participants with probable PTSD, a greater proportion of females had severe PTSD symptoms in comparison to males.

The association between PTSD symptom severity and cocaine use problems was different in males and females (Table 4). In females, a cocaine use disorder was associated with an increased risk of moderate and severe PTSD symptoms. While a cocaine use disorder was associated with a two-fold increase in the risk of moderate PTSD in males, a cocaine use disorder was not associated with any increase in the risk of severe PTSD symptoms. To check for effect modification, an interaction term was added to a logistic equation calculating the odds of moderate and severe PTSD. Males were used as the referent group. No effect modification was detected (OR = 1.13, 95% CI = 0.67–1.92, p > 0.05).

TABLE 4.

The Effect of Cocaine Use on PTSD Severity in Male and Female Community Outpatients

Multinomial Logistic Model Odds Ratio (95% CI) p Value
Males
Risk of moderate PTSD symptoms1
Substance Use Disorders2 <0.01
 No Cocaine Use Disorder 1.00 (reference)
 Cocaine Use Disorder 2.13 (1.23−3.68)
Age 1.00 (0.98−1.02) n.s.
Risk of severe PTSD symptoms1
Substance Use Disorders2 n.s.
 No Cocaine Use Disorder 1.00 (reference)
 Cocaine Use Disorder 1.93 (0.85−4.39)
Age 0.99 (0.96−1.02) n.s.
Females
Risk of moderate PTSD symptoms1
Substance Use Disorders2 <0.05
 No Cocaine Use Disorder 1.00 (reference)
 Cocaine Use Disorder 2.12 (1.10−4.10)
Age 1.02 (0.99−1.05) n.s.
Risk of severe PTSD symptoms1
Substance Use Disorders2 <0.01
 No Cocaine Use Disorder 1.00 (reference)
 Cocaine Use Disorder 2.87 (1.33−6.21)
Age 1.03 (0.99−1.06) n.s.
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1

No PTSD symptoms: Base outcome.

2

Adjusted for age.

DISCUSSION

These data suggest a significant association between cocaine use disorders and PTSD diagnosis. Cocaine users were more likely to have a probable PTSD diagnosis than non-cocaine users, even after controlling for other substance use. Females had greater rates of cocaine use problems, and more PTSD symptoms than males. A contribution of this data, not previously reported in the literature, is the unique role of gender in the association between PTSD symptom severity and cocaine use. For females, the risk of moderate and severe PTSD symptoms increased with the presence of a cocaine use disorder. Although males with a cocaine use disorder had two times the risk of having moderate PTSD symptoms, cocaine use disorders were not associated with an increased risk of severe PTSD symptoms.

Limitations of this study are inherent to the cross-sectional design; a limited dataset on substance use, PTSD, and other psychiatric symptoms; and a relatively homogenous sample. These liabilities pose threats to internal and external validity, and attenuate generalizability to more racially and ethnically diverse samples. The basic summary data provided by the three addiction treatment agencies did not include information regarding psychiatric diagnoses such as depression, method of cocaine use (i.e., powder, freebase, or crack), or severity of substance use, and types of traumatic events experienced. The cross-sectional design rendered impossible inferences on the chronology or sequence of symptom development: did cocaine use precede traumatic life events and PTSD symptoms, or did a traumatic life event lead to PTSD symptoms and subsequent cocaine use? These issues can only be examined within longitudinal repeated measure designs. Substance use and PTSD data were collected from chart diagnoses and self-report measures like the PCL, which are less rigorous than research-specific measures such as structured clinical interviews for PTSD and/or substance use.

This study provides important data on the relationship between cocaine use disorders, PTSD symptoms, and gender. In females, cocaine use disorders were associated with a greater risk for more severe PTSD symptoms. Although males with cocaine use disorders had no increased risk of severe symptoms, they were more likely to have moderate PTSD symptoms. In community addiction treatment programs, universal screening for mental health disorders, including PTSD, is recommended (CSAT 2005). The current data verify that treatment agencies should especially consider selected screening and assessment for PTSD among persons with cocaine use problems. Future research should strive to overcome the limitations of the present study. This would include a longitudinal design, more rigorous and detailed measures of PTSD, substance use and other psychiatric symptoms, and more ethnically and racially diverse sample. Whether or not the present findings are generalizable can only be determined with replication.

Acknowledgments

The authors would like to thank Clay Gilbert at Rutland Mental Health Center, Kurt White at Brattleboro Retreat, and Jennifer Spagnuolo at HowardCenter for assistance with data collection.

Footnotes

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

References

  1. Alterman AI, McDermott PA, Cook TG, Cacciola JS, McKay JR, McLellan AT, Rutherford MJ. Generalizability of the clinical dimensions of the Addiction Severity Index to nonopioid-dependent patients. Psychology of Addictive Behavaviors. 2000;14(3):287–294. doi: 10.1037//0893-164x.14.3.287. [DOI] [PubMed] [Google Scholar]
  2. Back SE, Brady KT, Jaanimagi U, Jackson JL. Cocaine dependence and PTSD: A pilot study of symptom interplay and treatment preferences. Addictive Behaviors. 2006;31(2):351–354. doi: 10.1016/j.addbeh.2005.05.008. [DOI] [PubMed] [Google Scholar]
  3. Back S, Dansky BS, Coffey SF, Saladin ME, Sonne S, Brady KT. Cocaine dependence with and without post-traumatic stress disorder: A comparison of substance use, trauma history and psychiatric comorbidity. American Journal on Addictions. 2000;9(1):51–62. doi: 10.1080/10550490050172227. [DOI] [PubMed] [Google Scholar]
  4. Blanchard EB, Jones-Alexander J, Buckley TC, Forneris CA. Psychometric properties of the PTSD Checklist (PCL) Behaviour Research and Therapy. 1996;34(8):669–673. doi: 10.1016/0005-7967(96)00033-2. [DOI] [PubMed] [Google Scholar]
  5. Brady KT, Dansky BS, Sonne SC, Saladin ME. Posttraumatic stress disorder and cocaine dependence: Order of onset. American Journal on Addictions. 1998;7(2):128–135. [PubMed] [Google Scholar]
  6. Bremner JD, Southwick SM, Darnell A, Charney DS. Chronic PTSD in Vietnam combat veterans: Course of illness and substance abuse. American Journal of Psychiatry. 1996;153(3):369–375. doi: 10.1176/ajp.153.3.369. [DOI] [PubMed] [Google Scholar]
  7. Burns MN, Lehman KA, Milby JA, Wallace D, Schumacher JE. Do PTSD symptoms and course predict continued substance use for homeless individuals in contingency management for cocaine dependence? Behaviour Research and Therapy. 2010;48(7):588–598. doi: 10.1016/j.brat.2010.03.010. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Center for Substance Abuse Treatment (CSAT) Substance Abuse Treatment for Persons with Co-Occurring Disorders. Rockville MD: Substance Abuse and Mental Health Services Administration; 2005. Treatment Improvement Protocol (TIP) series 42. [PubMed] [Google Scholar]
  9. Chen KW, Banducci AN, Guller L, Macatee RJ, Lavelle A, Daughters SB, Lejuez CW. An examination of psychiatric comorbidities as a function of gender and substance type within an inpatient substance use treatment program. Drug and Alcohol Dependence. 2011;118(2–3):92–99. doi: 10.1016/j.drugalcdep.2011.03.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Clark HW, Masson CL, Delucchi KL, Hall SM, Sees KL. Violent traumatic events and drug abuse severity. Journal of Substance Abuse Treatment. 2001;20(2):121–127. doi: 10.1016/s0740-5472(00)00156-2. [DOI] [PubMed] [Google Scholar]
  11. Cotto JH, Davis E, Dowling GJ, Elcano JC, Staton AB, Weiss SR. Gender effects on drug use, abuse, and dependence: A special analysis of results from the National Survey on Drug Use and Health. Gender Medicine. 2010;7(5):402–413. doi: 10.1016/j.genm.2010.09.004. [DOI] [PubMed] [Google Scholar]
  12. Currie SR, El-Guebaly N, Coulson R, Hodgins D, Mansley C. Factor validation of the addiction severity index scale structure in persons with concurrent disorders. Psychological Assessment. 2004;16(3):326–329. doi: 10.1037/1040-3590.16.3.326. [DOI] [PubMed] [Google Scholar]
  13. Dansky BS, Brady KT, Saladin ME. Untreated symptoms of PTSD among cocaine-dependent individuals: Changes over time. Journal of Substance Abuse Treatment. 1998;15(6):499–504. doi: 10.1016/s0740-5472(97)00293-6. [DOI] [PubMed] [Google Scholar]
  14. Dansky BS, Brady KT, Saladin ME, Killeen T, Becker S, Roitzsch Victimization and PTSD in individuals with substance use disorders: Gender and racial differences. American Journal of Drug and Alcohol Abuse. 1996;22(1):75–93. doi: 10.3109/00952999609001646. [DOI] [PubMed] [Google Scholar]
  15. Dansky BS, Byrne CA, Brady KT. Intimate violence and post-traumatic stress disorder among individuals with cocaine dependence. American Journal of Drug and Alcohol Abuse. 1999;25(2):257–268. doi: 10.1081/ada-100101859. [DOI] [PubMed] [Google Scholar]
  16. Falck RS, Wang J, Siegal HA, Carlson RG. The prevalence of psychiatric disorder among a community sample of crack cocaine users: An exploratory study with practical implications. Journal of Nervous and Mental Disease. 2004;192(7):503–507. doi: 10.1097/01.nmd.0000131913.94916.d5. [DOI] [PubMed] [Google Scholar]
  17. Ford JD, Gelernter J, DeVoe JS, Zhang W, Weiss RD, Brady K, Farrer L, Kranzler HR. Association of psychiatric and substance use disorder comorbidity with cocaine dependence severity and treatment utilization in cocaine-dependent individuals. Drug and Alcohol Dependence. 2009;99(1–3):193–203. doi: 10.1016/j.drugalcdep.2008.07.004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Ford JD, Hawke J, Alessi S, Ledgerwood D, Petry N. Psychological trauma and PTSD symptoms as predictors of substance dependence treatment outcomes. Behaviour Research and Therapy. 2007;45(10):2417–2431. doi: 10.1016/j.brat.2007.04.001. [DOI] [PubMed] [Google Scholar]
  19. Freeman RC, Collier K, Parillo KM. Early life sexual abuse as a risk factor for crack cocaine use in a sample of community-recruited women at high risk for illicit drug use. American Journal of Drug and Alcohol Abuse. 2002;28(1):109–131. doi: 10.1081/ada-120001284. [DOI] [PubMed] [Google Scholar]
  20. Griffin ML, Weiss RD, Mirin SM, Lange U. A comparison of male and female cocaine abusers. Archives of General Psychiatry. 1989;46(2):122–126. doi: 10.1001/archpsyc.1989.01810020024005. [DOI] [PubMed] [Google Scholar]
  21. Grubaugh AL, Elhai JD, Cusack KJ, Wells C, Frueh BC. Screening for PTSD in public-sector mental health settings: The diagnostic utility of the PTSD checklist. Depression and Anxiety. 2007;24(2):124–129. doi: 10.1002/da.20226. [DOI] [PubMed] [Google Scholar]
  22. Halikas JA, Crosby RD, Pearson VL, Nugent SM, Carlson GA. Psychiatric comorbidity in treatment-seeking cocaine abusers. The American Journal on Addictions. 1994;3(1):25–35. [Google Scholar]
  23. Hien DA, Campbell AN, Ruglass LM, Hu MC, Killeen TK. The role of alcohol misuse in PTSD outcomes for women in community treatment: A secondary analysis of NIDA’s Women and Trauma Study. Drug and Alcohol Dependence. 2010a;111(1–2):114–119. doi: 10.1016/j.drugalcdep.2010.04.011. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Hien DA, Jiang H, Campbell AN, Hu MC, Miele GM, Cohen LR, Brigham GS, Capstick C, Kulaga A, Robinson JA, Suarez-Morales L, Nunes EV. Do treatment improvements in PTSD severity affect substance use outcomes? A secondary analysis from a randomized clinical trial in NIDA’s Clinical Trials Network. American Journal of Psychiatry. 2010b;167(1):95–101. doi: 10.1176/appi.ajp.2009.09091261. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Hien DA, Nunes E, Levin FR, Fraser D. Posttraumatic stress disorder and short-term outcome in early methadone treatment. Journal of Substance Abuse Treatment. 2000;19(1):31–37. doi: 10.1016/s0740-5472(99)00088-4. [DOI] [PubMed] [Google Scholar]
  26. Hser YI, Stark ME, Paredes A, Huang D, Anglin MD, Rawson R. A 12-year follow-up of a treated cocaine-dependent sample. Journal of Substance Abuse Treatment. 2006;30(3):219–226. doi: 10.1016/j.jsat.2005.12.007. [DOI] [PubMed] [Google Scholar]
  27. Johnson CS, Heffner JL, Blom TJ, Anthenelli RM. Exposure to traumatic events among treatment-seeking, alcohol-dependent women and men without PTSD. Journal of Traumatic Stress. 2010;23(5):649–652. doi: 10.1002/jts.20563. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Johnson SD, Striley C, Cottler LB. The association of substance use disorders with trauma exposure and PTSD among African American drug users. Addictive Behaviors. 2006;31(11):2063–2073. doi: 10.1016/j.addbeh.2006.02.007. [DOI] [PubMed] [Google Scholar]
  29. Karila L, Petit A, Lowenstein W, Reynaud M. Diagnosis and consequences of cocaine addiction. Current Medicinal Chemistry. 2012;19(33):5612–5618. doi: 10.2174/092986712803988839. [DOI] [PubMed] [Google Scholar]
  30. Lang AJ, Laffaye C, Satz LE, Dresselhaus TR, Stein MB. Sensitivity and specificity of the PTSD checklist in detecting PTSD in female veterans in primary care. Journal of Traumatic Stress. 2003;16(3):257–264. doi: 10.1023/A:1023796007788. [DOI] [PubMed] [Google Scholar]
  31. Lange RA, Hillis LD. Cardiovascular complications of cocaine use. New England Journal of Medicine. 2001;345(5):351–358. doi: 10.1056/NEJM200108023450507. [DOI] [PubMed] [Google Scholar]
  32. Leonhard C, Mulvey K, Gastfriend DR, Shwartz M. The Addiction Severity Index: A field study of internal consistency and validity. Journal of Substance Abuse Treatment. 2000;18(2):129–135. doi: 10.1016/s0740-5472(99)00025-2. [DOI] [PubMed] [Google Scholar]
  33. Magura S, Kang SY, Rosenblum A, Handelsman L, Foote J. Gender differences in psychiatric comorbidity among cocaine-using opiate addicts. Journal of Addictive Diseases. 1998;17(3):49–61. doi: 10.1300/J069v17n03_05. [DOI] [PubMed] [Google Scholar]
  34. Mancino MJ, McGaugh J, Feldman Z, Poling J, Oliveto A. Effect of PTSD diagnosis and contingency management procedures on cocaine use in dually cocaine- and opioid-dependent individuals maintained on LAAM: A retrospective analysis. American Journal on Addictions. 2010;19(2):169–177. doi: 10.1111/j.1521-0391.2009.00025.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. McDonald SD, Calhoun PS. The diagnostic accuracy of the PTSD checklist: A critical review. Clinical Psychology Review. 2010;30(8):976–987. doi: 10.1016/j.cpr.2010.06.012. [DOI] [PubMed] [Google Scholar]
  36. McLellan AT, Kushner H, Metzger D, Peters R, Smith I, Grissom G, Pettinati HM, Argeriou M. The fifth edition of the Addiction Severity Index. Journal of Substance Abuse Treatment. 1992;9(3):199–213. doi: 10.1016/0740-5472(92)90062-s. [DOI] [PubMed] [Google Scholar]
  37. McLellan AT, Luborsky L, Cacciola J, Griffith J, Evans F, Barr HL, O’Brien CP. New data from the Addiction Severity Index: Reliability and validity in three centers. Journal of Nervous and Mental Disease. 1985;173(7):412–423. doi: 10.1097/00005053-198507000-00005. [DOI] [PubMed] [Google Scholar]
  38. Najavits LM, Gastfriend DR, Barber JP, Reif S, Muenz LR, Blaine J, Frank A, Crits-Christoph P, Thase M, Weiss RD. Cocaine dependence with and without PTSD among subjects in the National Institute on Drug Abuse Collaborative Cocaine Treatment Study. American Journal of Psychiatry. 1998;155(2):214–219. doi: 10.1176/ajp.155.2.214. [DOI] [PubMed] [Google Scholar]
  39. Najavits LM, Harned MS, Gallop RJ, Butler SF, Barber JP, Thase ME, Crits-Christoph P. Six-month treatment outcomes of cocaine-dependent patients with and without PTSD in a multisite national trial. Journal of Studies on Alcohol and Drugs. 2007;68(3):353–361. doi: 10.15288/jsad.2007.68.353. [DOI] [PubMed] [Google Scholar]
  40. Najavits LM, Lester KM. Gender differences in cocaine dependence. Drug and Alcohol Dependence. 2008;97(1–2):190–194. doi: 10.1016/j.drugalcdep.2008.04.012. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Najavits LM, Runkel R, Neuner C, Frank AF, Thase ME, Crits-Christoph P, Blaine J. Rates and symptoms of PTSD among cocaine-dependent patients. Journal of Studies on Alcohol. 2003;64(5):601–606. doi: 10.15288/jsa.2003.64.601. [DOI] [PubMed] [Google Scholar]
  42. Najavits LM, Weiss RD, Shaw SR, Muenz LR. Seeking safety: Outcome of a new cognitive-behavioral psychotherapy for women with posttraumatic stress disorder and substance dependence. Journal of Traumatic Stress. 1998;11(3):437–456. doi: 10.1023/A:1024496427434. [DOI] [PubMed] [Google Scholar]
  43. Ouimette P, Read JP, Wade M, Tirone V. Modeling associations between posttraumatic stress symptoms and substance use. Addictive Behaviors. 2010;35(1):64–67. doi: 10.1016/j.addbeh.2009.08.009. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Riezzo I, Fiore C, De Carlo D, Pascale N, Neri M, Turillazzi E, Fineschi V. Side effects of cocaine abuse: Multiorgan toxicity and pathological consequences. Current Medicinal Chemistry. 2012;19(33):5624–5246. doi: 10.2174/092986712803988893. [DOI] [PubMed] [Google Scholar]
  45. Rikoon SH, Cacciola JS, Carise D, Alterman AI, McLellan AT. Predicting DSM-IV dependence diagnoses from Addiction Severity Index composite scores. Journal of Substance Abuse Treatment. 2006;31(1):17–24. doi: 10.1016/j.jsat.2006.03.003. [DOI] [PubMed] [Google Scholar]
  46. Ruggiero KJ, Del Ben K, Scotti JR, Rabalais EA. Psychometric properties of the PTSD Checklist-Civilian Version. Journal of Traumatic Stress. 2003;16(5):495–502. doi: 10.1023/A:1025714729117. [DOI] [PubMed] [Google Scholar]
  47. StataCorp. Stata Statistical Software: Release 13. StataCorp LP; College Station, TX: 2013. [Google Scholar]
  48. Stecker T, Han X, Curran GM, Booth BM. Characteristics of women seeking intensive outpatient substance use treatment in the VA. Journal of Women’s Health. 2007;16(10):1478–1484. doi: 10.1089/jwh.2006.0237. [DOI] [PubMed] [Google Scholar]
  49. Substance Abuse and Mental Health Services Administration (SAMHSA) Results from the 2012 National Survey on Drug Use and Health: Summary of National Findings. Rockville, MD: Substance Abuse and Mental Health Administration (SAMHSA); 2013. [Google Scholar]
  50. Terhakopian A, Sinaii N, Engel CC, Schnurr PP, Hoge CW. Estimating population prevalence of posttraumatic stress disorder: An example using the PTSD checklist. Journal of Traumatic Stress. 2008;21(3):290–300. doi: 10.1002/jts.20341. [DOI] [PubMed] [Google Scholar]
  51. Tull MT, Gratz KL, Aklin WM, Lejuez CW. A preliminary examination of the relationships between posttraumatic stress symptoms and crack/cocaine, heroin, and alcohol dependence. Journal of Anxiety Disorders. 2010;24(1):55–62. doi: 10.1016/j.janxdis.2009.08.006. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Wasserman DA, Havassy BE, Boles SM. Traumatic events and post-traumatic stress disorder in cocaine users entering private treatment. Drug and Alcohol Dependence. 1997;46(1–2):1–8. doi: 10.1016/s0376-8716(97)00048-3. [DOI] [PubMed] [Google Scholar]
  53. Weathers FW, Litz BT, Herman DS, Huska JA, Keane TM. The PTSD checklist (PCL): Reliability, validity, and diagnostic utility. Paper read at 9th Annual Meeting of the International Society for Traumatic Stress Studies; San Antonio, TX. 1993. [Google Scholar]
  54. Weathers FW, Litz BT, Huska JA, Keane TM. PTSD Checklist: Civilian Version. Boston: National Center for PTSD, Behavioral Science Division; 1994. [Google Scholar]
  55. Wilkins KC, Lang AJ, Norman SB. Synthesis of the psychometric properties of the PTSD checklist (PCL) military, civilian, and specific versions. Depression and Anxiety. 2011;28(7):596–606. doi: 10.1002/da.20837. [DOI] [PMC free article] [PubMed] [Google Scholar]
  56. Wong CJ, Badger GJ, Sigmon SC, Higgins ST. Examining possible gender differences among cocaine-dependent outpatients. Experimental and Clinical Psychopharmacology. 2002;10(3):316–323. doi: 10.1037//1064-1297.10.3.316. [DOI] [PubMed] [Google Scholar]
  57. Wu LT, Pan JJ, Blazer DG, Tai B, Stitzer ML, Woody GE. Using a latent variable approach to inform gender and racial/ethnic differences in cocaine dependence: A National Drug Abuse Treatment Clinical Trials Network study. Journal of Substance Abuse Treatment. 2010;38(Suppl 1):S70–79. doi: 10.1016/j.jsat.2009.12.011. [DOI] [PMC free article] [PubMed] [Google Scholar]

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