Age of onset, adolescence and young adulthood

Women tend to start using alcohol and drugs slightly later in life than men, and there are often gender differences for motivation to start using. However, to many adolescents, female and male, experimentation with mood-altering substances is attractive and behavior of peers can contribute to this. For girls and young women whose onset of drug and alcohol use is the teenage years, there are particular risks: brains and bodies are still developing and susceptible to damage and some hormones that are thought to play a role in metabolism and in developing and maintaining addiction problems may be in a state of flux. Further, young women receive confusing messages about the acceptability of alcohol and drug use. Alcohol use is more acceptable now in young women, but when women do drink, particularly younger women, there is greater censure than for men when they drink excessively, and this censure comes from both women and men (de Visser et al., 2012).

A particular harm in young people who use alcohol and drugs is risk-taking, which may manifest itself in behaviors such as driving whilst intoxicated, or result in outcomes such as accidental injury. Women are less likely to engage in risk-taking behaviors, but such behaviors do still occur (e.g., Lex et al. 1994).

Girls are more likely to smoke for reasons of appetite reduction and weight control than boys and men, and, compared to boys who smoke, tend to have stronger peer attachments; to have parents and friends who smoke; to be less committed to school; and to have less knowledge about nicotine, addiction and prevalence of smoking (US Department of Health and Human Services 2001). Escalating rates of smoking in young girls have recently been noted in Southeast Asia – whereas smoking rates for women in general are one-tenth of those for men; for 13–15 year olds, boys are only 2.5x more likely to smoke than girls (Hammond 2009).

Transition to problematic use

Although fewer women than men use drugs, alcohol and nicotine, those who do tend to have a more rapid acceleration of use than men, and this appears across drugs such as alcohol, cannabis, cocaine and opiates/opioids (Brady 1999, Hernandez-Avila 2004). The transition in women from use to hazardous use to harmful use to dependence is less clear. Late 20s is often a time when women cut back on use, and both marriage and pregnancy seem to have a protective effect in reducing substance use (Leonard & Eiden 2007). Child-rearing is often accompanied by less money and less time, along with the increased responsibilities of motherhood, and these all may contribute to how mothers modify their drinking and drug-taking behavior.

Women transition to problematic alcohol use more quickly than men (Zilberman et al. 2003). The reproductive years also carry increased risks of harm for women who misuse alcohol. Alcohol misuse can disrupt the menstrual cycle and reproductive function and has been implicated in infertility and spontaneous abortion (Jones et al., 2008). Women who binge drink are more likely to engage in risky sexual behaviors, with increased risk of both sexually transmitted diseases (Thomas et al. 2001) and unplanned pregnancy (Naimi et al. 2003). There is also some evidence in young women that alcohol use by both perpetrator and victim is a risk factor for sexual assault (Abbey 2002; Mohler-Kuo 2004).

There is clear evidence of a quicker transition in cocaine use too: women begin taking cocaine earlier, then progress from initial use to dependence more rapidly than men and enter treatment earlier. They also report higher levels of craving in response to cues, and if they relapse, have longer periods of use than men (Becker & Hu 2008). These findings are supported by animal studies, where sex differences are consistently found in the area of cocaine self-administration (Roth et al. 2004).

Women who have transitioned into cannabis misuse show increased analgesia, depression, anxiety and catalepsy compared to men. Further, they show increased sexual behavior, whereas in men the opposite is the case (Fattore & Fratta 2010).

In opiates, findings differ, although some studies do suggest that women escalate more rapidly to problematic use than men and experience addiction in a shorter period (Anglin et al. 1987, Hser et al. 1987, Greenfield et al. 2007). However, women are somewhat less likely to have injected than men, although if they do inject, they are more likely to share needles than men (24% vs. 17%) (NTA 2010), leading to increased risk for blood-borne viruses such as Hepatitis A, B and C, and HIV. Menstrual disorders have also been associated with opiate use (Busch et al. 1986) and are thought to be caused by disruption to the hypothalamic pituitary axis (HPA) (Vuong et al. 2010).

Nicotine is highly addictive and the transition to dependence can take as little as 3 months (WHO 2011). There is also evidence that nicotine has specific effects on sexual and reproductive health and smoking has been implicated in infertility problems, ectopic pregnancies and preterm problems including preterm delivery, stillbirth, neonatal deaths, Sudden Infant Death Syndrome and lower birth weight (US Department of Health and Human Services 2001).

Addiction in middle age

Middle age is when many of the physical and psychological consequences of long-term substance misuse begin to take their toll. The contribution of alcohol to mortality and morbidity increases (Jones et al. 2008). The health risks of smoking are well documented and also begin to manifest themselves in middle age. In women, smoking is a major cause of mortality and morbidity from various cancers, coronary heart disease, stroke and chronic obstructive pulmonary disease (US Department of Health and Human Services 2001), and women have a 1.5-to-2-fold higher risk for lung cancer than men at the same level of tar exposure (Harris et al. 1993).

Further problems for women can occur when children grow into adults and leave the family home, and some women may question their social roles (Nolen-Hoeksema 2004). Rates of divorce and separation are higher in middle age and these are risk factors for women for alcohol misuse (Leonard & Eiden 2007).

Reproductive problems may continue in middle age. The onset of menopause is earlier in women who misuse alcohol than in women who do not (Eagon 2010) and women smokers are also at increased risk of early menopause (US Department of Health and Human Services 2001).

Addiction in the elderly

For many women, numerous challenges accompany old age: bereavement, failing physical health, depression, isolation, loneliness and poverty. Those who have developed addiction problems over the lifespan may be particularly difficult to identify in old age. Shame and stigma are particularly prevalent in this group and symptoms of, for example, alcohol dependence might be mistaken for symptoms of dementia, and vice versa (NIAAA 1998). Further, for those who take medications, there may be harmful interactive effects between those medications and alcohol. Elderly women appear to be particularly vulnerable to addiction to opioid-based painkillers, and at time of writing the CODEMISUSED project at http://codemisused.org is investigating this group in the UK, Ireland and South Africa.

For elderly women who smoke, there are increased risks of osteoporosis. Postmenopausal smoking women have lower bone density and increased risks of hip fractures than do nonsmoking women (WHO 2010).

Consequences over the life span

Although on a population level women suffer fewer harms from addiction than men, there is good evidence that women are suffering increasing addiction-related harms over the life span (e.g., Jones et al. 2008, Jones et al. 2011). This has been exacerbated by the increase in women’s use of alcohol and drugs over the past few decades, within a context of economic development and changing gender roles. A well-recognized phenomenon is that of the “telescoping effect,” when women transition to dependence more rapidly than men, and suffer greater harms more quickly and with less consumption/use than men. This phenomenon has been found in a range of addictive drugs and behaviors, including alcohol (e.g., Diehl et al. 2007) and gambling (Slutske et al. 2014).

The WHO estimates that alcohol contributes to 4% of deaths in women, compared to 7.6% in men, but women appear to be more vulnerable to alcohol-related harm than men: while intoxicated, they have higher Blood Alcohol Content (BAC) after consuming the same amount of alcohol (Nolen-Hoeksema 2004). Women also suffer memory blackouts while drinking much lower levels of alcohol than men (White et al. 2002). With longer-term, chronic alcohol misuse, women develop alcohol liver injury and cirrhosis having consumed less alcohol than men and for a shorter time, and it is suggested that, as well as body mass and composition of fat versus water, sex hormones play a part in this (Eagon 2010).

There is enormous variation from country to country. In the United States, alcohol-related deaths averaged 26,000 for women and 62,000 for men between 2006 and 2010. Rates of harms are strongly correlated with rates of consumption: in the Russian Federation, consumption is high and 6% of deaths among women are attributable to alcohol misuse (Kerr-Correậ et al. 2007). In England, alcohol contributes to 2.0% of deaths in women, compared to 4.4% in men. There are differences in causes of alcohol-attributable deaths across the life course: under the age of 25, the leading cause is intentional self-harm; between the ages of 25 and 34 spontaneous abortion; between the ages of 35–54 mental and behavioral disorders; post 55 hypertensive diseases; and over 75 cardiac arrhythmias (Jones et al., 2008).

In drug-taking populations, women may also have poorer health outcomes: Neale (2004) reports women drug takers scoring significantly lower on six out of eight health dimensions than men.

Alcohol and drugs are also significant contributors to a range of health harms; Table 15.4 lists the key harms associated with use of addictive substances.

Biological

Biological risk factors for women are considered in four main areas: metabolism, genes, sex hormones and neuroscience.

Women have differences in biological mechanisms relating to the metabolism of alcohol and to body water content, compared to men. This means that women are more likely to experience harm related to drinking at the same level of alcohol consumption, even controlling for body mass (Zakhari 2006). Levels of alcohol dehydrogenase tend to be lower in women, resulting in less efficient metabolism of alcohol and higher levels remaining in the bloodstream (Frezza et al. 1990). In smoking, women have greater sensitivity to the effects of nicotine at lower levels, and do not take in as much nicotine as men (Benowitz 1998). However, in pregnant women and in women taking oral contraceptives, metabolism of nicotine is much higher than in women who are not (Dempsey et al. 2002, Matta et al. 2007). Metabolic differences have also been noted in cannabis users, with women taking longer to clear tetrahydrocannabinol (THC) than men, which is thought to be related to the lipophyllic properties of THC and the greater proportion of fat in women’s bodies. In benzodiazepines, gender differences have been observed in both directions, with some linked to faster metabolism, and some linked to lower (Howell et al. 2001).

Sex hormones are also thought to contribute to risk factors for the harms associated with alcohol misuse in women (Eagon 2010). Gonadal hormones are thought to contribute to neurobiological sex differences in cannabinoid action (Fattore & Fratta 2010). In animal models, estrogen has been found to facilitate drug-seeking behavior, whereas progesterone has been found to reduce drug seeking, contributing to an increased vulnerability in females. There may also be different responses to substances at different stages in the menstrual cycle: in human studies, increased responsivity to stimulants has been observed during the follicular phase, but lower responsivity during the luteal phase (Sofuoglu et al. 1999). Other candidates for sex differences, particularly in treatment responses, are the hypothalamic pituitary axis (HPA), dopamine (DA) and gamma-hydroxy-butyric acid (GABA) (Carroll & Anker 2010). Oral contraceptive pills have been noted to affect clearance rates, in both directions, of different types of benzodiazepine (Howell et al. 2001)

Recent research has started to find different associations between neurobiological processes underlying motivations for drug and alcohol use in women and men. Becker et al. (2012) propose that sex differences in brain function may contribute to different pathways to addiction for women and men. They hypothesize that more men than women begin taking drugs for sensation-seeking reasons, receiving positive reinforcement of drug taking initially in the form of euphoria (related to dopamine, norepinephrine, endogenous opioids and acetylcholine), which over time becomes negative reinforcement, leading to dysphoria and eventually to drug dependence. Women, they argue, are less likely to initiate drug use for the positive euphoriant effects. (See also Bobzean et al. 2014.)

Most studies in genetics suggest that genes play a role in alcohol misuse in both women and men, with heritability estimates in both groups clustering at around 50%. Early genetic studies suggested that alcohol misuse might be more heritable in men than in women, although more recent reviews suggest this is not the case (Plomin et al. 2008, Agrawal & Lynskey 2008). Genetic factors are thought to contribute to smoking initiation, where women have higher rates of heritability than men (66% vs. 49%) (Hamdani et al. 2006).

Social

Women experiencing adverse life events or family problems are known to be more vulnerable to substance misuse than men (Copeland & Hall 1992). Divorce and separation are risk factors for alcohol misuse (Leonard & Eiden 2007). It is also known that childhood sexual abuse plays a role in later substance misuse. Almost two-thirds of US women drug users in treatment reporting physical, sexual or emotional abuse in childhood (National Institute for Drug Abuse [NIDA] 1998). In Scotland nearly two-thirds of women in treatment report physical abuse and one-third report sexual abuse (McKeganey et al. 2005).

Rates of domestic violence are particularly high in women with addiction problems and often run alongside comorbid psychiatric problems, so much so that practitioners refer to addiction, domestic violence and mental health problems as a “toxic triangle” in women. Alcohol is particularly implicated in domestic violence and a myriad of studies across low- and middle-income countries consistently demonstrate a strong association between alcohol use in men and experiencing domestic violence in women. A large portion of partner violence occurs after drinking and the risks are particularly high during heavy episodic drinking (for an in-depth review see Heise 2011). See also Chapter 14.

There is mixed evidence in women for the role of socioeconomic status and social roles in increased alcohol consumption and related problems (Nolen-Hoeksema, 2004). Traditionally, feminine traits such as nurturance appear to be protective factors against alcohol misuse, although this is the case in both sexes. Women, however, perceive greater social censure than men (Nolen-Hoeksema 2004) and, for women drug takers, stigma is known to be a particularly pertinent issue (Brown 2011). Recent decades have seen increased targeting of alcohol and nicotine advertising and branding specifically at women, from sugary alcohol drinks in pink packaging marketed as low calorie, to “light” cigarettes, smoked by two-thirds of women compared to one-half of men (Shifman et al. 2001).

Retention in treatment

The longer a person with addiction problems remains in treatment, the more likely a successful outcome, so much so that retention in treatment is measured as a treatment outcome in its own right in some countries (Marsden et al. 2008). However, treatment drop-out rates are concerningly high for both women and men, as those who leave treatment are less likely to address their addiction problems. Despite best efforts, researchers have been unable to identify clear reasons why people drop out of treatment. Although there do not appear to be gender differences in treatment retention, gender-specific factors have been identified that improve treatment retention in women, including social support, psychological functioning, personal stability, low levels of anger, belief in treatment efficacy and referral source. These run alongside factors that improve outcomes for both women and men: fewer mental health problems, less severe addiction problems and access to greater financial resources (Greenfield et al. 2010).