The present study confirmed the findings of other studies (Messina et al., 2003
; Peters et al., 1997
) that women offenders in a prison substance abuse treatment have more lifetime mental health difficulties than their male counterparts. The present study expanded upon these findings in that it examined gender differences in a range of lifetime psychiatric disorders and associated lifetime DSM-IV psychopathology. In a sample of offenders newly admitted to various types of prison substance abuse treatment, women were significantly more likely than men to report a lifetime psychiatric disorder, affective disorder, anxiety disorder, and severe psychiatric disorder. Furthermore, women reported greater lifetime major depression, PTSD, eating disorder, and borderline personality disorder. Men in this sample were twice as likely to meet criteria for antisocial personality disorder.
Compared with women in the community, the women in this study were nearly twice as likely to have any affective disorder, a major depressive disorder (Kessler et al., 1994
), or PTSD (Kessler et al., 1995
), and have a greater likelihood of borderline personality disorder (Torgersen, Kringlen, & Cramer, 2001
). Since these disorders have been associated with sexual and physical abuse (Molnar, Buka, & Kessler, 2001
; Trull, Sher, Minks-Brown, Durbin, & Burr, 2000
) and past studies have reported higher rates of these traumas among incarcerated women than incarcerated males (Langan & Pelissier, 2001
; Messina et al., 2003
), perhaps an abuse history increases the vulnerability of female offenders with substance use to psychiatric comorbidity. A model that has been proposed to understand the link between childhood abuse, psychopathology, and substance use is the self-medication model. It has been postulated that childhood abuse disrupts the development of affect-regulation skills, which predisposes an individual towards developing psychopathology, such as PTSD, depression, and borderline personality disorder. Substances are then used in an attempt to medicate the profound symptoms of these disorders (Epstein, Saunders, Kilpatrick, & Resnick, 1998
; Herman, 1992
; Zlotnick et al., 2006
). A treatment that focuses on affect management skills, such as Dialectical Behavior Therapy, which has been found to be an efficacious treatment for women with drug dependence and borderline personality disorder (Linehan et al., 1999
), might be beneficial to female incarcerated substance users with comorbid disorders associated with childhood sexual abuse.
The only disorder for which men were more likely to meet criteria than women was antisocial personality disorder. Another study of offenders in a prison substance use program found no gender differences for this disorder (Langan & Pelissier, 2001
). This latter study used a sample of federal prisoners whereas the current study used a sample of state prisoners. Differences between the studies' samples may account for the divergent results. Also, our finding that men were significantly more likely to have committed assault than women may have contributed to the relatively high proportion of men with a diagnosis of antisocial personality disorder.
The gender difference in degree of internalizing disorders in the current study is consistent with the finding that more women than men reported lifetime major depression, PTSD, and suicidality, given that the internalizing disorder subscale of the GSS includes both depression, anxiety disorder, traumatic distress, and suicide. The finding of a higher degree of internalizing disorders in women suggests that incarcerated women, despite their criminal behavior, tend to have a similar profile in terms of psychiatric morbidity to women in the community, who have also been found to report more internalizing psychopathology than their male counterparts (Rosenfield, 2000
). It is possible, however, that the gender differences found in this study (and other studies) reflect women's greater willingness to self-disclose symptoms, especially those related to the internalizing disorders of depression, anxiety, and traumatic stress.
Unlike women in the community, men in our study did not report a higher degree of externalizing behaviors than women. Since externalizing behaviors are highly related to substance use severity (Dennis et al., 2006
) and our study did not find gender differences in substance use severity, perhaps substance abuse severity accounted for the lack of gender differences in externalizing behaviors. Also, the externalizing subscale scale of the GSS taps symptoms related to attention deficit and hyperactivity/impulsivity: disorders that are likely to be more prevalent among incarcerated women than women in the general community.
In contrast to most other studies with drug-involved prisoners (e.g. Messina et al., 2003
; Peters et al., 1997
), the current study found no significant gender differences in recent (within the last six months) severity of substance use or in type of drug used, except that women in our study were more likely to report intravenous drug use. Obvious differences in study findings may be attributable to different designs, including different measures of severity of substance use, as well as different time periods in which studies were conducted, which may be associated with different patterns of drug use. Nevertheless, the fact that there was a gender difference in lifetime intravenous drug use, not measured by other studies, suggests that incarcerated women in prison substance use treatment programs have engaged in more serious drug use than their male counterparts prior to incarceration.
Limitations of this study include the cross-sectional design of the study, which precludes the study from addressing important issues concerning the temporal relationship between substance use disorder and comorbid psychiatric disorders. Research in the general community suggests that individuals with comorbid disorders tend to report that their first mental disorder occurred at an earlier age than their first substance disorder (Kessler, 2004
). Longitudinal, prospective studies will contribute to our understanding of how substance use among incarcerated women is related to psychiatric impairment. Another limitation of this study is that it did not differentiate current from past psychiatric disorders, as there was limited power to detect differences due to the low number of cases for many of the psychiatric disorders of interest. Finally, the findings derive from prisoners who chose to participate in a prison substance use program and may not generalize to other prison populations.
Despite these limitations, this study concludes that women offenders who enter various types of prison substance use program present with greater psychiatric vulnerability and a different pattern of psychiatric comorbidity than their male counterparts. This finding highlights the importance of comprehensive psychiatric evaluations for inmates entering a substance abuse prison program, especially for women. The gender difference in psychiatric comorbidity found in this study also suggests the need for gender-specific treatment. Many women in prison substance abuse treatment must address two distressing and often interactive disorders. Future research is needed to address the etiological, therapeutic, and organizational implications of gender differences in psychiatric comorbidity among offenders in a prison substance abuse treatment.