In 2016, two editorials published in leading journals The Lancet and Addiction highlighted how little is known about women and drugs
. Not only did these editorials point to a blind spot in our collective knowledge, but they suggested that this deficit has been compounded by a lack of female scientists investigating the issue. Men dominate the science and editorial leadership of academic journals. There are a number of factors that have led to us having less knowledge about problematic drug use in women than in men.
Drug misuse is not a niche activity, with one-third of adults using an illicit drug at least once in their lifetime. Adding regulated drugs such as alcohol and tobacco raises population-level drug use further. However, there are distinct gender differences. In most national surveys of drug use, men tend to outnumber women by two to one. The British Crime Survey has found this ratio to be stable over time, recording this gender difference since 1996
Women accelerate from initiation to problematic drug use faster than men
Zooming in from population-level use of drugs to the gender difference in specialist treatment, the ratio increases with more than three males for every female
, although this ratio narrows for those seeking help for problems with alcohol. But this perspective of gender and drug use misses some important nuanced detail. For example, women accelerate from initiation to problematic drug use faster than men, a phenomenon referred to as “telescoping” 
. This is thought to be because of physical and psychological susceptibility to the effects of drugs, including alcohol, where women have generally been found to develop liver disease more rapidly than their male counterparts.
More men present to specialist treatment and it is more convenient for researchers to recruit samples from this setting, so this leads to an underrepresentation of women in research samples. This is mirrored in trials of new medicines, where women are often excluded for fear that these substances may be particularly toxic to females. Paradoxically, a greater proportion of women then report experiencing adverse reactions to these medicines
More generally, even when women are included in trials testing new treatments, the outcomes are often not reported in the results
. So although the data are collected, this is not shared in publication outputs. This limits our understanding of the specific problems encountered and of how effective treatment interventions are for women, because these have mostly been tested on men.
There are clear disincentives that deter women from seeking treatment, such as fears about the risk that their children may be taken into care. Intimate partner violence is a further factor that prevents women from seeking treatment, because they worry about aggravating an existing dysfunctional or violent relationship if they are found to be seeking support
Misuse of prescription drugs appears to be the one area of problematic drug use where equity between the sexes is achieved. A recent pan-European study found that while men still outnumber women, the gender ratio narrows considerably, particularly for non-medical use of sedatives such as benzodiazapines
. More research is needed to understand the reasons for this and what type of support is effective and acceptable to women in helping them eliminate non-medical use of prescription drugs.
A point often overlooked in relation to drug use is that a small percentage of individuals account for the majority of consumption
. This has clear health implications because using drugs frequently or in high quantities is often a risk factor for developing a range of physical and mental health problems.
A small percentage of individuals account for the majority of drug consumption
For women there are particular risks. For young and middle-aged females, binge drinking alcohol has been found to be associated with increased fasting plasma glucose in non-diabetic women
. This is the most significant risk factor for future development of type 2 diabetes. This information could be used by public health to try to persuade adolescent females to moderate their alcohol consumption to mitigate future health risks.
Women, drugs and crime
Women offenders’ use of drugs is greater than men, with 66% of women reporting committing an offence to get money to buy drugs compared with 38% of men
. Women also have higher rates of self-harm and are at higher risk of contracting HIV as a result of drug use. The good news is that, once women are in treatment, they are more likely to engage, stay longer and have improved outcomes over men. However, just as with men, many women are reluctant to seek help in the first place and have distinct reasons for wanting to avoid contact with agencies 
. Women with children may avoid treatment because they have fears about being judged as being an unfit parent because of their use of drugs. Also, many women have experienced initimate partner violence or been exploited sexually, and both factors make the male-dominated treatment environment difficult places to be.
Just as with men, many women are reluctant to seek help in the first place
When women around the world come into contact with the penal system the response to their health needs is varied, as is respect for their human rights. Internationally, there needs to be political will to invest time and resources into these women. This might happen soon, with the newly elected director general of the World Health Organization, Tedros Adhanom Ghebreyesus, stating that the wellbeing of women will be one of his top priorities
. A global perspective and, more importantly, action matters, as more women are imprisoned for drug-related offences than any other crime.
In the main, drug policy is muted on the issue of gender, perhaps influenced by the evidence base, which has focused disproportionately on men. So even if policy makers are inclined to attend to the specific needs of women, they have little in the way of evidence to draw from. When policy does make mention of women, this is almost exclusively in relation to pregnancy, an important aspect but not the only issue that impacts on women and their use of drugs. There is emerging evidence of women’s needs, such as a lack of childcare. One study highlights the specific needs women have at the point of entering specialist treatment
. By comparing pathways into and out of drug use for men and women, the researchers argue that gender-based assumptions miss factors that could be significant, such as sexual orientation, age, socioeconomic status and ethnicity.
When policy does make mention of women, this is almost exclusively in relation to pregnancy
To have any impact on practice, thinking should be strategic because research informs policy which, in turn, directs the commissioning of services. The UK government, as with other governments, has shifted the policy emphasis from one centred on harm reduction to one based on recovery from drug dependence and problems. A recent analysis of this policy shift found that women are largely ignored, which shores up the perception that the male drug user is the norm
The bias towards attending to men extends beyond patients and is more systemic in nature. As the editorial in Addiction pointed out, women are underrepresented at every level of scientific enquiry, although the differences are most obvious higher up the academic hierarchy
, with only 29% of senior editorial positions held by women. We need to attract the brightest and the best minds to investigate the issue of women and drugs. By levelling the gender balance in academia we would not only bring a fairer career path, but have the potential to provide greater insight, with female academics who may be more likely to be tuned into the problems that women who develop problems with drugs experience.
Several journals have signed up to the Sex and Gender Equity in Research guidance, which goes some way towards both trying to improve reporting of outcomes for women in trials and promoting the career paths of female academics
So whether you are a woman who is studying drug use or a woman experiencing drug problems, there is commonality — both groups are hampered by a lack of attention and face a struggle to achieve their potential. In this way we all lose out.
Ian Hamilton is a lecturer in mental health at the University of York
Disclosure: Ian Hamilton is affiliated with Alcohol Research UK
 Home Office. Drug Misuse: Findings from the 2015/16 Crime Survey for England and Wales. 2016. Available at: https://www.gov.uk/government/statistics/drug-misuse-findings-from-the-2015-to-2016-csew (accessed 28 June 2017)
 Public Health England. Adult substance misuse statistics from the National Drug Treatment Monitoring System (NDTMS) 2016. Available at: http://www.nta.nhs.uk/statistics.aspx (accessed 28 June 2017)
 Zakiniaeiz Y, Cosgrove KP, Potenza MN et al. Focus: sex and gender health: balance of the sexes: addressing sex differences in preclinical research. Yale J Biol Med 2016;89(2):255. PMCID: PMC4918870
 Gilchrist G, BlÃ¡zquez A, Torrens M. Exploring the relationship between intimate partner violence, childhood abuse and psychiatric disorders among female drug users in Barcelona. Adv Dual Diagn 2012;5(2):46-58. doi: 10.1108/17570971211241895
 van Laar M, Frijns T, Trautmann F et al. Cannabis market: User types, availability and consumption estimates. Available at: https://dspace.library.uu.nl/handle/1874/309585 (accessed 28 June 2017)
 Nygren, K. Hammarstrom, A. Rolandsson, O. Binge drinking and total alcohol consumption from 16 to 43 years of age are associated with elevated fasting plasma glucose in women: results from the northern Swedish cohort study. BMC Public Health 2017;17:509 doi: 10.1186/s12889-017-4437-y
 Bromley briefings prison fact file. 2016 Available at: http://www.prisonreformtrust.org.uk/Publications/Factfile (accessed 28 June 2017)
 Neale J, Nettleton S, Pickering L. Gender sameness and difference in recovery from heroin dependence: a qualitative exploration. Int J Drug Policy 2014;25(1):3–12. doi: 10.1016/j.drugpo.2013.08.002
 EASE Gender Policy Committee. Making visible the invisible: development of the guidelines on sex and gender equity in research (SAGER). 6th World Congress on Women’s Mental Health, 22–25 March 2015, Tokyo, Japan.