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Research Advances Volume 12, Number 4 July/August 1997

Gender Affects Relationships Between Drug Abuse and Psychiatric Disorders

By Neil Swan, NIDA NOTES Staff Writer

In the general population, women are more than twice as likely as men to suffer depression. But among cocaine and alcohol abusers, men are as likely to be diagnosed with depression as women, a NIDA-funded study indicates.

Why? Is cocaine more likely to trigger depression among men than among women? Perhaps.

Researchers have long been aware that many drug abusers also have serious mental disorders, a status referred to as dual diagnosis or comorbidity. Does the psychiatric disorder precede and perhaps con-tribute to the onset of drug abuse? Or, conversely, do drug abuse and addiction develop first, perhaps contributing to the development of the mental disorder?

A study conducted by Dr. Kathleen T. Brady and her colleagues at the Medical University of South Carolina provides insights into these questions. The researchers examined gender differences in psychiatric disorders among 100 treatment-seeking cocaine and alcohol abusers. Among these substance abusers, comorbidity with mental disorders was substantive. Some 48 percent of the men and 70 percent of the women had a comorbid affective or anxiety disorder. In addition, a substantial number were also dually diagnosed with other mental disorders including passive- aggressive, obsessive-compulsive, and antisocial personality disorders. Some 56 percent of the men and 68 percent of the women abusers had one or more of these additional disorders, either alone or with an affective or anxiety disorder.

The study's preliminary findings suggest that both onset scenarios - drug abuse first or mental disorder first - sometimes may occur. It is possible that the sex of the drug abuser may be a factor in determining which comes first, depending on the comorbid psychiatric disorder involved.

In the case of depressive episodes, Dr. Brady's study suggests that for women, depression comes first more often; for men, drug abuse appears to come first more often. Because cocaine has such powerful effects on the brain, it may be that in many people cocaine use activates depressive episodes that linger after the period of euphoria and withdrawal, she says. "Perhaps men are at greater risk for this response to cocaine, which would help explain the lack of gender differences in depression rates among cocaine abusers we studied compared to rates in the general population," explains Dr. Brady. Also, men typically consume more alcohol and use more cocaine, which would increase the damaging effects of these substances, which, in turn, might lead to depression, she adds.

The study shows that women more often than men were diagnosed with not just depression but with other psychiatric disorders as well before they began using drugs (see bottom table). For example, as with depression, women are significantly more likely than are men to have a diagnosis of panic disorder before the onset of drug abuse, says Dr. Brady, a psychiatrist. Panic disorder is manifested in sudden attacks of acute anxiety or terror that may be uncontrollable.

The most dramatic gender difference in prevalence rates found by the South Carolina researchers was in the diagnosis of posttraumatic stress disorder (PTSD) - emotional shock ignited by the threat of death or actual or threatened injury resulting in severe fear, feelings of helplessness or horror, and recurrent memories. Of the 50 men and 50 women whom Dr. Brady studied, some 46 percent of women were diagnosed with lifetime PTSD, compared to only 24 percent of the men (see top table).

Social phobia - extreme shyness and fear of embarrassment and humiliation or performance anxiety such as stage fright - was found in 12 percent of the study group compared to only 2.8 percent of the population at large, which other studies have shown. The onset of social phobia predated drug abuse in 100 percent of both women and men diagnosed with the disorder in this study. This suggests that patients may use drugs to self-medicate their social phobia, says Dr. Brady.

Other epidemiologic studies have shown that social phobia is 1.5 times more common in women than men. "But we found little gender difference in the prevalence of social phobia in the group of substance abusers," she says. "This means that while social phobia is a risk factor for substance abuse in both sexes, it appears that it may be a greater risk factor for men. Perhaps cultural expectations for men to be more socially aggressive prompt men more to use drugs or alcohol to overcome shyness and other aspects of social phobia."

The study found no gender differences in the study group in prevalence of other psychiatric disorders such as antisocial personality disorder, paranoid or schizoid personality disorders, or obsessive-compulsive disorder. In general, the study demonstrates important gender differences in some psychiatric disorders, but not in others, among the substance abusers and compared to the population at large.

Dr. Brady's data on these disorders show similar rates of prevalence for these diagnoses in men and women. Particularly for antisocial personality disorder, these similar rates are in contrast to several earlier studies, she notes. In the general population, as well as in alcoholics and opiate abusers, a higher prevalence of antisocial personality disorder in men than in women has been reported. But in one earlier study of psycho-pathology in cocaine abusers, no significant gender differences in antisocial personality disorder rates were noted. The majority of the women in her study were cocaine-dependent, which may partially explain the discrepancy between her data and some of the other studies, Dr. Brady says.

Her study results imply that different psychiatric factors may have differing roles prior to - or in response to - drug abuse in women compared to men, says Dr. Brady. These preliminary findings are important indicators for designing research to develop and implement improved gender-specific drug abuse treatment strategies, says Dr. Cora Lee Wetherington, NIDA's Women's Health Coordinator. In another study, Dr. Brady examined cocaine-abusing men and women who also were diagnosed with PTSD, dividing them by order of onset of diagnosis - cocaine first or PTSD first. In the cocaine-first group, the PTSD-causing trauma was generally related to the dangers involved in procuring and using cocaine and was more common among men. In the PTSD-first group, the trauma was generally childhood abuse and was more common among women, the study found. For women, PTSD preceded cocaine dependence in 77 percent of the cases; for men, this figure was 38 percent.

"Because much of the PTSD in substance-abusing women appears to be closely related to the sexual and physical victimization of women, my colleagues and I are now investigating this relationship in hopes of finding new treatments for PTSD and drug abuse that would address important gender differences," Dr. Brady says.

Sources

Brady, K.T.; Dansky, B.; Saladin, M.; and Sonne, S. PTSD and cocaine dependence: The effect of order of onset. Presentation at annual meeting of the College on Problems of Drug Dependency. San Juan, P.R., 1996.

Brady, K.T.; Grice, D.E.; Dustan, L.; and Randall, C. Gender differ-ences in substance use disorders. American Journal of Psychiatry 150(11):1707-11, 1993.

From NIDA NOTES, July/August 1997

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