The addition of the gender perspective to the study of drug addictions in recent years has generated new ways of understanding the usage patterns of new consumers [10, 15, 26, 27]. This approach allows for the identification of male and female consumption patterns and makes female usage more visible.

When analyzing TSSp nonmedical use among Spanish adolescents, our results indicate that for the study decade, comprised from 2004 to 2014, the prevalence of nonmedical use of prescription medicine has experienced a significant increase of around 6 % in the female school population residing in Spain (aOR = 1.06, 95% CI 1.04–1.08). These results agree with those obtained during 2002 and 2005 by the United States (US) National Survey on Drug Use and Health (NSDUH), which indicated that US female adolescents presented higher rates of nonmedical use of tranquilizers and sedatives than male adolescents [28]. The investigation performed by Young et al. by means of the systematic review of the scientific bibliography on nonmedical use of prescribed medicines in adolescents found that, in most of the studies, female gender was more associated with tranquilizer use [29]. Also, the Brazilian study by Opaleye et al. shows that female adolescents have twice the probability (aOR = 2.19; 95% CI: 1.75–2.75) of reporting nonmedical use of these medicines than males [20].

When identifying patterns for TSSp nonmedical use among the Spanish school population, we found that the only socio-demographic variable in our study that acted as a predictor for the nonmedical use of these drugs, both in male and female adolescents, was unemployment for both parents. Some studies have indicated that students with a low socio-economic status present a greater tendency to consume substances in their adolescence [30, 31]. This relationship is described in studies such as that by Bali et al., in which they noted that individuals with family incomes lower than $20,000 were more likely to make nonmedical use of prescription drugs [32]. Also, in the Canadian study performed with data from the Canadian Health Behavior in School-Aged Children study, results indicated that students with a lower socioeconomic status (SES) were 2.41 times more likely to make recreational use of any type of drug [24].

When we analyzed the consumption of legal psychoactive substances and their relationships with the nonmedical use of TSSp, we found that alcohol use and smoking in adolescent females were significantly associated with the nonmedical use of these prescription drugs. This revealed a growing trend towards the incorporation of female adolescents into the consumption ranks of these legal drugs, surpassing male consumption rates [23, 26]. Recent research shows that the gender gap in alcohol consumption is decreasing [33]. These changes in normative standards, mainly for alcohol consumption, are contributing to a series of gender gaps within Spanish society that could be related to the fact that female adolescents associate alcohol consumption with pleasure, and they now consume alcohol in public places [34].

With regard to adolescents, cannabis is the only illegal psychoactive substance whose consumption has increased among the Spanish female population in recent years, probably due to the normalization and acceptance of such use, as well as its low risk perception [35]. In our study, marijuana consumption was associated with TSSp nonmedical use in the school population of both genders. Several studies indicate that the probability of using marijuana increases among those adolescents who report nonmedical use of benzodiazepines and anxiolytics [36]. A recent US study assessing longitudinal associations between the nonmedical use of sedatives and anxiolytics during adolescence found that approximately 92.9% of the adolescents also consumed other psychoactive substances, mainly alcohol and cannabis [37].

In line with that, illegal psychoactive substance consumption is a risk factor related to starting nonmedical use of prescription drugs among adolescents. A cross-national study of the nonmedical use of prescription medications in five European countries found that 28% of those who engaged in nonmedical use of sedatives in the previous year had also consumed illegal drugs [5]. Our study showed that the use of illegal psychoactive substances was the factor most strongly associated with TSSp nonmedical use among school adolescents of both genders. Male Spanish adolescents who reported that they consumed illegal drugs were six times more likely to make nonmedical use of these medicines. Similar results were obtained in a study performed in 31 European countries with data from the European School Survey on Alcohol and Other Drugs, the results of which showed that those adolescents who engaged in nonmedical use of tranquilizers and sedatives were 3.48 times more likely to consume illegal drugs [23]. In recent years, there has been an increase in illegal drug consumption among younger females although differences between female and male consumption rates remain considerable. These data have given rise to the so-called “convergence hypothesis”, which states that differences between males and females in drug use are lessening and are expected to continue in this same vein [38].

The use of drugs among adolescents has increased due to the low risk perception associated with their consumption. Therefore, it will be necessary to identify the factors that have led to this perception and to the corresponding increase in addictive drug behavior rates among adolescents [39]. The low risks perceived for TSSp nonmedical use among Spanish teenage students makes them 3 times more likely to consume drugs than those adolescents who perceive such consumption as highly risky. This agrees with data from a national survey performed with adolescents of both sexes, the results of which showed that those participants with a low risk perception of consumption (aOR = 1.53 95% CI 1.09–2.15) were the most prone to nonmedical use of tranquilizers and sedatives [21]. If we take together the low risk perception and the ease of obtaining TSSp for our adolescents, mainly among girls (6.50% indicate that they find it easy or very easy to obtain them), the problem is aggravated, since these two variables are associated with the nonmedical use of these medicines. We should bear in mind that drugs are often used by other family members through medical prescription and are, therefore, available inside adolescents’ homes. This can make adolescents conclude that their behavior is not that at odds with social standards, since their use complies with adult models. The access availability of TSSp is also reflected in other studies which show that 20.7% of students agreed that obtaining tranquilizers and sedatives was “very easy” or “quite easy” and indicated that the first drug they ever abused belonged to their parents [33, 40].

The scientific community has accepted the incorporation of the gender perspective to drug consumption, since women and men respond to different constraints and, therefore, any analysis, strategy or action, should separately contemplate and study the aspects and factors conditioning them. The question analyzes real life and circumstances for males and females in a separate manner with the objective of identifying how gender constraints affect the issue of drug consumption.

One of the main strengths of this study is the application of a gender perspective to a nationally representative sample in order to study the prevalence of the nonmedical use of TSSp in school populations over a decade. Given that the methodology of the ESTUDES survey is similar to that used in other European Union countries and the United States, we feel empowered to make international comparisons.

However, our study is subject to a series of limitations. The first limitation of surveys about drug abuse comes from the cross-sectional nature of the study data, which does not allow for establishing the direction of the associations discovered.

The second limitation comes from using self-declared data. Thus, the prevalences obtained to generate nonmedical use profiles for tranquilizers, sedatives and/or sleeping pills could be underestimated. This is because, due to sociocultural judgments surrounding the consumption of such substances, some school adolescents will have reservations about openly confessing their prescribed or self-medication consumption of these medications.

We also need to point out that the non-response rate (between 9 and 17.1% (ESTUDES)), affects our estimations of reported consumption, since those adolescents who refused to participate could share certain characteristics related to consumption, although the direction of the effect cannot be determined [35].