Official data about sexual offences show that the prevalence of sex crimes is relatively low among criminal behaviours. For example, reported sex crimes accounted for only 0.94% of all the serious crimes committed in Spain in 2014 (Dirección General de Instituciones Penitenciarias, 2014). Nonetheless, the number of sex offences not officially reported by victims may be substantially higher (Abrahams et al., 2014).

However, sex offences are among the most serious crimes because of their severe damage to the victims, usually women and children (Echeburúa & Guerricaechevarría, 2011; European Agency for Fundamental Rights, 2014; Fergusson, McLeod, & Horwood, 2013; Lopez-Castroman et al., 2013; Wößner, 2016). Also, sexual offences carry a huge social stigma and, justifiably, arouse intense feelings of personal insecurity. Particularly, the crimes committed by sex offenders released after serving their sentences generate public concern and alarm.

For all these reasons, it is important to analyse and enhance our scientific understanding of sexual offending behaviour in order to improve prevention and to apply more effective treatment with convicted offenders. This paper focuses specifically on the effectiveness of the psychological treatment administered to rapists or sex offenders serving prison sentences in Spain for sexual assaults on adult women1.

The initiation and development of human sexuality from puberty generally involves a range of appropriate prosocial experiences which normally include sexual self-satisfaction and voluntary sexual interaction with peers. As a result of these sexual experiences, during adolescence individuals usually learn prosocial sexual repertoires and also acquire the necessary sexual controls, inhibitions, and taboos, in particular with regard to avoiding forced sex. However, juveniles who have suffered serious traumatic experiences in childhood (psychological or sexual abuse, inconsistent rearing in the family, and so on) may have special difficulty in developing these indispensable sexual controls and inhibitions, and as a result show more risk of sexual offending (Becker & Johnson, 2001; Hamby, Finkelhor, & Turner, 2012; Marshall, Laws, & Barbaree, 2013; Marshall, Marshall, Serran, & Fernandez, 2006; Redondo & Martinez, 2012; Zurbriggen, Gobin, & Freyd, 2010). In this respect, a significant proportion of sex offenders have more varied and atypical sexual experiences at an early age than is the norm, including the use of violent pornography (Barbaree & Langton, 2006; Becker & Hunter, 1997; Cale, Smallbone, Rayment-McHugh, & Dowling, 2016; Seto & Eke, 2015) or actual childhood experiences of physical or sexual abuse (Fergusson et al., 2013; Gunby & Woodhams, 2010; Mancini, Reckdenwald, & Beauregard, 2012; Seto, 2008). These experiences of victimisation may stimulate a deviant sexual arousal and a preference for violent sex.

Rapists may also have suffered traumatic family abandonment, affective rejection, negligent parents, erratic styles of upbringing, and so on during childhood (Maniglio, 2012). These traumatic early experiences tend to be related to severe emotional and communicative deficits, relationship problems, and social isolation (Ford & Linney, 1995; Hendriks & Bijleveld, 2004; Hulme & Middleton, 2013; Katz, 1990; Porter, Newman, Tansey, & Quayle, 2015; Van Wijk, 1999). To solve or compensate these problems, individuals may use inappropriate coping mechanisms such as a hyper-sexualisation of their emotionality and conduct, including deviant fantasies and masturbation (Mancini et al., 2012; Marshall & Marshall, 2014).

On the other hand, rapists usually show numerous “cognitive distortions”, that is, erroneous thoughts about women in general, their victims in particular, and the feasibility of the use of violence in social interactions. Such thoughts hamper their capacity to properly interpret and recognise the emotions, needs, desires, and intentions of others and in particular of their victims (Abel, Becker, & Cunningham-Rathner, 1984; Craig, Browne, Beech, & Stringer, 2006; Hempel, Buck, van Vugt, & van Marle, 2015; Marshall, Marshall, & Kingston, 2011; Merdian, Curtis, Thakker, Wilson, & Boer, 2014; Whitaker et al., 2008). In some individuals, cognitive distortions about sexual interactions have a leading aetiological role in their sexual offending, while in other cases cognitive distortions operate mainly not as aetiological factors but as post hoc rationalisations for justifying their actions (Maruna & Mann, 2006; Ward, Hudson, Johnston, & Marshall, 1997).

Many rapists also show severe deficits in empathy and social skills. They tend to exhibit a marked egocentrism and severe difficulties in imagining and figuring out realistically what others, and particularly their victims, might think, want, and feel (Cohen & Strayer, 1996; Fernandez & Marshall, 2003; Geng, Xia, & Qin, 2012). Several studies have found a direct relationship between individuals’ early sexual victimisation and exposure to pornography and the lack of empathy shown later by sex offenders (Becker & Johnson, 2001; Fergusson et al., 2013; Hempel et al., 2015; Mann & Barnett, 2013; Marshall, Marshall, Serran, & O’Brien, 2009). These empathic deficiencies may also undermine the rapists’ ability to establish meaningful and appropriate interpersonal relationships, including interactions at school and at work, and the establishment of affective bonds (Agnew, 2014; Beavin, 2015).

Some rapists are versatile offenders, in the sense that their criminal behaviour is not restricted to sexual offences but may extend to theft, physical assault, and so on. This versatility may contribute to consolidating and stabilising the rapist's criminal career, since sexual and nonsexual crimes may interact reciprocally as a part of a more general, chronically deviant life style (Lussier, 2005; Piquero, Farrington, Jennings, Diamond, & Craig, 2012; Seto & Lalumière, 2010; Sewall, Krupp, & Lalumière, 2013; Sigre-leirós et al., 2016).

As can be seen, many sex offenders display numerous personal and social deficits and risk factors (including feelings, attitudes, values, and behaviours) often associated with their criminal conduct (Beech & Mann, 2002; Marshall et al., 2013; Marshall & Marshall, 2014). In order for sex offenders to desist from crime, favourable changes in all of these risk factors are required (Brown, 2015; Day, Casey, Ward, Howells, & Vess, 2010). Thus, the main objective of the current psychological interventions with sex offenders (which are generally applied within the prison setting) is to promote individuals’ internal changes. This includes a more realistic interpretation of their crimes and behavioural consequences, as well as the improvement of empathy, self-esteem, assertiveness, and so on.

Current theories surrounding sex offenders’ rehabilitation propose to focus interventions on the abovementioned deficits and risk factors in order to reduce recidivism risk (Abbey, Jacques-Tiura, & LeBreton, 2011; Andrews, Bonta, & Wormith, 2011; Beech, Mandeville-Norden, & Goodwill, 2012; Echeburúa & Amor, 2010; Marshall et al., 2013; Rich, 2009). Particularly, it needs to be focussed on the change of dynamic risk factors or criminogenic needs, which are those modifiable variables commonly associated with an increased offending risk (Andrews & Bonta, 2016; Andrews & Dowden, 2007). Different meta-analyses have concluded that therapeutic effectiveness with offenders increases as many criminogenic needs (and fewer non-criminogenic needs) are addressed (Hanson, Bourgon, Helmus, & Hodgson, 2009a; Martínez-Catena, Redondo, Frerich, & Beech, 2016; Mcgrath, Cumming, Burchard, Zeoli, & Ellerby, 2009).

The criminogenic needs most commonly associated with sexual recidivism and also addressed in sex offender treatments are: intimacy deficits, hostility towards women, emotion regulation problems, social isolation or rejection, impulsivity, poor cognitive problem-solving skills, and sexual deviation (Hanson et al., 2009a; Hanson & Morton-Bourgon, 2004; Lussier, 2005; Yates, 2009).

Other factors, despite their lower direct empirical relationship with sexual recidivism, are included in sex offenders’ treatment as long as they could enhance treatment responsivity and participants self-efficacy (Mcgrath et al., 2009). They are factors like denial or minimization, low self-esteem, lack of empathy, general psychological problems, etc.

For instance, McGrath et al. (2009) highlighted that 90% of sex offender programs include a victim empathy component, despite research indicating that a lack of victim empathy is not firmly related to recidivism (Mann, Hanson, & Thornton, 2010). Nevertheless, empathy could be useful as a treatment objective, as it is strongly correlated with self-esteem, shame, and cognitive distortions, possibly influencing each other in treatment improvement (Marshall et al., 2009). In this way, changes in self-esteem as a result of treatment are highly correlated with changes in empathy over the course of treatment (Marshall, Anderson, & Champagne, 1997). Also, Webster and Beech (2000) found that offenders’ empathy deficits in relation to their victims were strongly related to measures of cognitive distortions.

Similarly, cognitive distortions are strongly related to the aetiology of sexual offence behaviour, but their relationship with treatment efficacy is complex. In terms of treatment, cognitive distortions are assessed and treated both as crime precipitant and maintaining factor (Hudson, Wales, Bakker, & Ward, 2002). Nonetheless, a recent meta-analytic review showed a significant association between the improvement of attitudes (one of the possible processes involved in cognitive distortions) and the reduction of sexual recidivism (Helmus, Hanson, Babchishin, & Mann, 2013). Furthermore, it has been found that cognitive distortions can be tied back to emotions which are treated through the self-management component in sex offenders’ rehabilitation processes (Abracen & Looman, 2016). So, teaching participants to recognize and differentiate emotions from each other (in particular sadness, anxiety, anger, hostility, loneliness, and shame) could help to reduce cognitive distortions about violence.

Taking into account this close relationship between several criminogenic needs, it is expected that simultaneously addressing each variable in treatment would help improve participant's other personal and social difficulties that are not directly included in the intervention program.

At present, the most frequently applied and most effective sex offenders’ treatments are the cognitive-behavioural programmes based on the Risk-Needs-Responsivity (RNR) model (Andrews & Bonta, 2016; Prentky, Righthand, & Lamade, 2016; Prentky & Schwartz, 2006). A pioneering treatment programme for sex offenders was initially developed in Canada by Marshall and his team (Barbaree & Langton, 2006; Barbaree & Marshall, 2006; Brown, 2015; Marshall, Marshall, Serran, & O’Brien, 2011), which has become the foundation of most subsequent sex offender programmes in different countries. For instance, in the UK the Home Office Prison Service designed specific versions for sex offender treatment (Brown, 2015; Hollin & Palmer, 2006): the Sex Offender Treatment Programme, SOTP core, whose central therapeutic aim is the confrontation and restructuring of cognitive distortions and crime justifications; the SOTP Adapted Programme for sex offenders with intellectual disabilities; the Better Lives Booster SOTP Programme, a follow-up treatment for higher risk individuals; a treatment format for lower risk offenders; a more modern intervention for internet sexual offenders; interventions for sex offenders in the community, and so on. Other European countries that also offer specialised programmes for sex offenders at prisons or in the community are Sweden2, Norway3, Denmark, Finland4, Holland, and Belgium.

As far as treatment effectiveness is concerned, the interventions applied with sex offenders in different countries in general show positive results. The recidivism rate of treated sex offenders ranged between 9% to 11%, compared with a rate of around 17% for untreated sex offenders (Hanson et al., 2009a; Hanson, Bourgon, Helmus, & Hodgson, 2009b; Hanson, Gordon, & Harris, 2002; Hanson & Morton-Bourgon, 2004; Lösel & Schmucker, 2005; Marshall & Marshall, 2014).

In Spain, the first specific programme for sex offenders was created by Garrido and Beneyto (1996, 1997) based on the programmes applied in other countries and aiming to meet the specific therapeutic needs of imprisoned sex offenders. The Sexual Offending Control Programme (SOCP) is a cognitive-behavioural intervention based on the RNR model, similar to the programmes applied with sex offenders in Canada, the US, and the UK (Marshall, Marshall, & Kingston, 2011; Marshall, Marshall, Serran et al., 2011; Olver & Wong, 2013). The SOCP was applied for the first time in 1996 in two prisons in Barcelona and its use subsequently extended to other Spanish prisons. A revised version of the programme (Ministerio del Interior, 2006) is currently administered in more than 40 Spanish prisons. Some of the results of these trials are analysed in this paper.

The SOCP lasts for one to two years. It is group-based, administered to both rapists and child molesters, and delivered twice weekly in sessions lasting about two and half hours. The treatment focuses on the following intervention elements: 1) relaxation training; 2) analysis of history and personal development of each subject; 3) cognitive distortions; 4) emotional regulation; 5) violent behaviour; 6) coping techniques; 7) empathy with victims; 8) training for a positive way of life; 9) sex and health education; 10) change of sexual impulse; and 11) relapse prevention.

The first effectiveness assessment of the SOCP was published in 2005 by Redondo and colleagues, who compared a group of 49 treated sex offenders with a similar group of 74 untreated peers. After a four-year follow-up, the official recidivism rate of treated sex offenders was 4.1% compared with 18.2% in the untreated group: a 14-point reduction (Redondo, 2006; Redondo, Navarro, Martínez, Luque, & Andrés-Pueyo, 2005).

A second evaluation of the SOCP, conducted independently in a prison in Madrid, obtained very similar results (Valencia, Andreu, Minguez, & Labrador, 2008). From a group of 22 treated sex offenders, 4.5% relapsed compared with a rate of 13% in the control group (n=21).

The evaluation of recidivism after treatment is an essential measure in a criminal matter as serious as sexual offending (Marshall & Marshall, 2014). But, at the same time, measuring recidivism alone is clearly insufficient in order to understand how the treatment works and to identify the personal changes that treatment promotes in offenders. For this reason, the Spanish Prison Management Service recently decided to complement the assessment of recidivism with the analysis of the individuals’ therapeutic change, or therapeutic efficacy. The Psychological Assessment Scale for Sex Offenders (PASSO) was designed for this evaluation (Redondo, Martínez, Ramírez-Pérez, & Martínez-Catena, 2016), whose main objective is to assess the specific therapeutic changes and improvements experienced by sex offenders as a result of their participation in the programme (Martínez-Catena et al., 2016; Redondo, Martínez-Catena, & Luque, 2014).

The present study describes this evaluation of the therapeutic efficacy of the SOCP, aiming above all to assess the possible therapeutic changes produced in rapists after participation.

As a general hypothesis, we expected participants in treatment to present overall improvements on the different psychological variables that are the therapeutic objectives of the programme. We also expected the various therapeutic variables assessed to improve after treatment, though not at the same rate.

In recent years, considerable support has been given for the development of treatment programmes for prison inmates and for the evaluation of their effectiveness. Given the gravity of their offences, rapists represent a particularly important subsample of the prison population. They are the focus of the therapeutic efficacy analysis presented here.

The current paper is an evaluation of the sex offenders’ treatment program applied in Spain since 2005, the Sexual Offending Control Programme (SOCP). Here, individual therapeutic changes are assessed through the specific scale called the Psychological Assessment Scale for Sex Offenders (PASSO) (Redondo et al., 2016). The PASSO scale evaluates ten therapeutic variables (including assertiveness, cognitive distortions about women and the use of violence, impulsivity, etc.). According to the literature, improvements in these variables as a result of treatment are positively associated with rehabilitation and desistance from crime. For each respondent, the PASSO provides a global therapeutic improvement score and ten specific scores corresponding to the different therapeutic subscales assessed.

The analysis of therapeutic improvement of this paper was carried out in a sample of 153 treated rapists. The analysis of overall therapeutic change in subjects revealed a significant improvement in the participants between pre and post-treatment assessments.

In parallel, regarding subjects’ changes on the different specific therapeutic variables, the intra-subject comparison also showed participant improvements on most of the assessed subscales (eight out of ten variables).

The post hoc effect sizes of these therapeutic subscales also put forward that the changes between the pre- and post-periods were distributed unevenly between the different variables. The therapeutic change scores in the pre- and post-treatment assessments in the participants ranged from small to moderate. Besides, the difference found in the PASSO overall score between the periods was moderate and statistically significant.

The results of the administered analyses suggest a general therapeutic improvement in this population of rapists in Spanish prisons.

Pearson's correlations revealed numerous associations between the different therapeutic variables assessed with PASSO. Those results are congruent with other studies that highlight the fact that different criminogenic needs may be highly correlated and possibly influence each other in treatment. In the analyses presented here it can be seen that the subscale decrease of impulsivity was associated with reduction of aggressiveness which could be an expected result. But also, similarly to the results previously presented by Marshall et al. (1997), Marshall et al. (2009), and Webster and Beech (2000), interesting associations have been found between different subscales. For instance, reduction of feelings of loneliness and improvement of self-esteem (which in the literature are not considered strong criminogenic need) are highly connected to relevant criminogenic needs such as decrease of impulsivity and reduction of aggressiveness. This suggests that the improvement of one of these factors could enhance the improvement of the others.

Furthermore, the association found between decrease of impulsivity and the subscales decrease of sexual anxiety and decrease of cognitive distortions against women is important to note. In practice this association could be rather helpful as these specific criminogenic needs are the most difficult to work with. That is, the application of one specific therapeutic technique could also benefit the later application of other techniques. An example is to practice “relaxation” (used commonly for impulsivity control) prior to the initiation of “cognitive distortions’ detection” (in the context of cognitive restructuration).

The analysis of specific therapeutic variables, as proposed here, could help to identify the elements that are likely to be most useful and effective, and also the ones that may require more intensity and commitment. It may help to guide decisions regarding the inclusion, modification, or elimination of some of the current components of interventions in sex offenders.

In general, in studies of therapeutic effectiveness it is difficult to determine whether the changes observed are mainly due to the treatment administered. The present study is no exception. Theoretically, other reasons could also explain the rapists’ individual changes observed here. For instance, imprisoned offenders may improve over time without receiving specific treatment for a variety of reasons, such as the natural development of subjects with age, a decrease in impulsivity and aggressiveness, or the positive effects of general educational activities inside prisons such as formal education, workshops, work, and so on.

Nevertheless, some of the empirical results obtained seem to suggest that participants show an overall therapeutic improvement and for a variety of specific therapeutic changes. At the same time, these positive changes would increase the probability of rehabilitation and desistence from crime.

A relevant methodological shortcoming, which precludes any conclusive claim that the positive changes were directly produced by treatment, is the absence of a control group. Another methodological limitation of this study is that some PASSO items may be too transparent and the subjects learn to give “better” responses in the post-treatment assessment.

In spite of these methodological limitations, the results presented here suggest that interventions with rapists in Spanish prisons have a moderate therapeutic efficacy. To our knowledge, this is the first comprehensive assessment of this issue conducted in Spain that goes beyond the standard, non-specific studies of recidivism rates.

Over the past decades, important advances have been made in the understanding and the prevention and treatment of rape, but major challenges still remain. For instance, as far as the aetiology of sexual aggression is concerned, we are familiar with many of the associated correlates and factors, such as affective deficits and traumatic sexual experiences, family neglect, low self-esteem and so on. But we still know little of the dynamic processes that mediate between these experiential factors and the specific onset of sexually deviant and criminal behaviour.

Huge scientific challenges remain regarding the prevention of this criminal activity and the treatment of rapists and other sex offenders. Most of the current preventive efforts in this area have concentrated on the application of specialised treatments, which essentially reach the individual level of this problem. Nevertheless, in the future, other kinds of preventive actions at educational and community level will probably be necessary to prevent, or at least control, sexual aggression more effectively.

This research was funded by grants SEJ2005-09170-C04-01 and PSI2009-13265 from Ministerio de Ciencia y Innovación [Spain's Ministry of Science and Innovation] and by grant PSI2013-47043-C2-2-R from Ministerio de Economía y Competitividad [Spain's Ministry of Economy and Competitiveness]. Financial support (FBG305486) was also provided by the Secretaría General de Instituciones Penitenciarias del Ministerio de Interior, Gobierno de España [Correctional Services, Home Office, Government of Spain].

The authors of this article declare no conflict of interest.