The Effectiveness of Human Systems Therapy (HST) on Intimate Partner Violence (IPV): An Empirical Study in Greece ()
1. Introduction
1.1. Theoretical/Research Background
Intimate Partner Violence (IPV) is a global phenomenon, primarily manifesting as violence against women, according to the World Health Organization (WHO, n.d.) . Similar findings are reflected in the records of the European Institute for Gender Equality (EIGE, n.d.) , where, among other things, it is evident that these rates in Greece are among the highest in Europe. This is further supported by data from the General Secretariat for Family Policy and Gender Equality (n.d.) , which attests that spousal and partner violence, separately and cumulatively, is the predominant form of violence against women in Greece. Similar findings emerge locally, particularly in Crete, specifically in Heraklion, based on reports from the SOS helpline (n.d.) and the Public Prosecutor’s Office. In Heraklion, there has been an increase in cases of domestic violence between spouses/partners, primarily reported by the victims and processed through criminal mediation by the Public Prosecutor’s Office in accordance with Article 11 of Law 3500/2006. The following information was provided by the Prosecutor’s Office at the request of the researcher (Table 1).
From the above, it can be concluded that the need for effective therapy for violent couples, which concerns global research, is particularly significant in the region. This present study focuses on the treatment of physical violence in couples using the HST model, following a referral by the Prosecutor’s Office to the HST Family Clinic in Heraklion.
1.2. Treatment of Intimate Partner Violence
Therapeutic interventions aim to eradicate intimate partner violence and change various individual and relational characteristics, depending on the theoretical framework and epistemology of each intervention model and the methods employed for therapy. Integrated therapeutic interventions, a trend in recent years, attempt to enhance the effectiveness of pure intervention models by expanding the points of intervention (Broderick & Schrader, 1981; Gurman & Fraenkel, 2002; Snyder, 1999; Dudley et al., 2008) .
Psychological theories recognise the abuse of power and control by perpetrators of intimate partner violence (Hyde-Nolan & Juliao, 2012) . The role of power
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Table 1. Cases in Public Prosecutor’s Office of Heraklion per year.
and control varies depending on the theoretical orientation of each theory, with psychoanalytic theories focusing on individual intrapsychic processes that lead to the need for violence or acceptance of violence and social theories emphasising the learning of aggression, violence, and abuse within the family. Respectively, cognitive-behavioural theories examine the transmission of behaviours from individuals to others, including intergenerational transmission, and finally, systemic theories focus on the interactions among family members and the sharing of responsibility for events occurring within the family system (Hyde-Nolan & Juliao, 2012) . Additionally, other theories, such as the feminist theory, focus on patriarchal societies that foster and cultivate a similar structure within the family, where male dominance over women is expected (Hyde-Nolan & Juliao, 2012; Bell & Naugle, 2008) .
In the ongoing international research for more effective intervention models, the search for the causes of intimate partner violence continues, along with the search for the form it may have in each case and the development of appropriate therapeutic responses in terms of epistemology, methodology, and treatment methods (Johnson & Greenberg, 1995; Saunders, 2017; Snyder, 1999; Sander, 1979; Karakurt et al., 2016) .
1.3. Models of Therapy for Conflictual and Violent Couples
Few internationally recognised models have documented and empirically supported effectiveness in treating conflictual and violent partners (Downes & Jeronimus, 2022; APA Task Force, 2006; APA, 2011; Cluss & Bodea, 2011; Eckhardt et al., 2013) . To our knowledge, the therapeutic models that meet the above criteria consist primarily of variations and adaptations of five basic models. Two of these models are systemic: Solution-Focused Brief Therapy (SFBT)—as a basis—and Emotionally Focused Therapy (EFT). The non-systemic ones are Narrative Therapy (White, 2008) , interventions based on Cognitive-Behavioral theory (Beck, 2020) and Collaborative Therapy (Anderson & Gehart, 2007) . For the purposes of this paper we will focus specifically on systemic models.
Solution-Focused Brief Therapy (de Shazer, 1991; Levin, 2007; Oka & Whiting, 2011) does not, to our knowledge, have treatments specifically for intimate partner violence to show, as violent couples are excluded. In couple-group therapy seeking relationship improvement, it increased relationship satisfaction, couple cohesion, consensus, and expressions of affection (Zimmerman, Prest, & Wetzel, 1997) . In another study of couple-group therapy, seven individuals from five couples reported improved relationship satisfaction (Nelson & Kelley, 2001) . When implementing a differentiated model of SFBT in cases of couples with violent conflicts, it was found that the model is unsuitable for every form of violence unless combined with another form of intervention. However, it was more effective in reducing aggression and increasing satisfaction (Stith et al., 2005; 2011) . In the initial meta-analysis of SFBT, there was limited effectiveness of the model in addressing family and relational problems. In an evaluation study of a therapy program for domestic violence perpetrators, findings showed a recidivism rate of 16.7% amongst participants over a period of 6 years and a significant improvement in relationship skills and self-esteem (Lee & Sebold, 2004) .
Emotionally Focused Therapy (EFT) (Johnson & Greenberg, 2013; Greenberg, 2015, 2017; Schneider & Brimhall, 2014) does not, to our knowledge, have specific treatments for intimate partner violence, as violent couples are excluded. However, Slootmaeckers & Migerode (2019) show in a case study that in the first stage of EFT (cycle de-escalation, where couples understand the negative interaction cycle that causes distress in their relationship), the model can effectively help reduce intimate partner violence in cases of situational violence. In a literature review framework, the application of EFT in conflictual couples has shown significant effectiveness and long-lasting changes. The benefits of couple therapy include increased relationship satisfaction, increased intimacy, and decreased complaints (Wiebe & Johnson, 2016; Wiebe et al., 2016, 2017) . Similar findings regarding improvement in marital satisfaction, facilitation of change during therapy and long-term outcomes are reported in a meta-analysis spanning nineteen years by Beasley & Ager (2019) . A decade-long outcome study by Denton et al. (2012) further expands the effectiveness of EFT in major depression coexisting with relationship distress (Lebow et al., 2012) .
2. The Human Systems Therapy (HST)
The HST model for violent couples is a systemic model that has evolved from the family therapy approach of HST and has been developed over time by professor of Psychiatry N. Paritsis. HST has been empirically tested with very good results in treating families with a member suffering from severe psychiatric problems such as schizophrenia (see Paritsis, 2010 ), as well as in family therapy (see Paritsis, 2022 ). This research is the first empirical application of the model in treating intimate partner violence (IPV).
HST considers the couple as an open cognitive system in which its members (parts), their relationships, and the emerging properties (behaviour) within their environment (context) interact (Paritsis, 2006, 2010) . The three levels make the intervention multi-level, and the focal point for problem-solving (but also satisfaction, evolution and development) is in human relationships regardless of the level of intervention. At the same time, change spreads across multiple system levels with multiplicative effects, according to the systemic principle. The General System Principles, the unconscious with palaeologic thinking, the epistemology of autosynthesis, synthesis with the environment, and the motives for interaction compose the epistemology of the model. Intervention in relationships is done using techniques in combination with the conjoint couple therapy applied by HST, facilitating changes in the members and their properties. Undesirable emotions and behaviours, as well as the content of cognitive-emotional structures and relationship schema, change within the context of relationships, resulting in changes in the collective intelligence of the couple/family (Paritsis, 2003, 2006, 2010, 2012, 2020, 2022) .
HST differentiates itself from other systemic models primarily at the level of epistemology. It intervenes at more levels and utilises the past in a therapeutic manner (intergenerational examination) in contrast to SFBT and EFT. Additionally, it supplements the principles and methods of the two Cybernetics approaches, in contrast to other models that reject the First Cybernetics. This position affects the perception of reality and the role of the therapist. In HST, the therapist is not just an observer or someone with no knowledge or an advisor of the process, but more of a specialist, who can also use effective First Cybernetic techniques combined with techniques developed within HST. The Hypothesis (aetiology) for violence in HST pertains to the system of the couple itself rather than the context as in SFBT. In terms of intervention, HST is the only intervention that does not exclude violent couples or types of violence, conducts conjoint couple therapy (with rare, brief individual meetings), and is a brief therapy of 5 - 9 sessions, without combining therapy with other therapeutic models. Finally, HST perceives the causality of violence as circular and dispersed, while SFBT does not attribute pathology to violence, and EFT attributes it to attachment bond trauma.
The dominant hypothesis regarding violence in HST:
In the search for causality in violence, HST proposes as a starting point the disruption of the hierarchical position of the couple members in combination with other factors (CDC, 2021; Papadakaki et al., 2009) . Usually, the perpetrator’s position ceases to be equal or was never equal, to begin with, within the relational system, based on the sociocultural reference framework (Paritsis, 2022) . The disruption of hierarchy, even for a certain period, brings about disorder (conflicts, illnesses, etc.). The restoration of the hierarchy in human systems is encountered in the theory and therapeutic models of First Cybernetics, and it has its basis in the Structural Model (Minuchin, 1974) . HST does not intervene linearly with the perpetrator or the victim but seeks causality within the couple and other systems (including transgenerational causality) (circular and/or dispersed causality) (McCollum & Stith, 2008; Bograd, 1992; Goldner et al., 1990) .
3. The Research-Intervention
The implementation of the HST intervention model to violent couples
The purpose of the research was to evaluate the effectiveness of implementing the intervention model of HST in violent intimate relationships.
Research hypothesis: We hypothesise that the therapeutic model of HST can bring about a change in violent couple relationships, with a statistically significant reduction in conflicts, frequency, and intensity. Additionally, positive emotions towards the partner after the intervention will be statistically significant.
Research methodology: A Multiple Case Study was applied (Yin, 2003) , as the nine cases that received treatment belong to a unique collection of individual cases that share a common characteristic/situation, which is intimate partner violence (Stake, 2006) .
Sample
Eighteen individuals comprised the nine Cases of violent heterosexual couples who participated (and completed) in the research/intervention using the HST model. The sample, originating from the same Regional Unit, initially consisted of ten men and women, one of whom relocated, leading to the termination of their treatment. Six couples were of Greek nationality, and three were foreign nationals from the same country. Almost all couples were middle-aged and had children (except one). Additionally, almost all participants had stable but low to moderate educational levels (ISCO 08). Table 2 provides the sociodemographic data of the participants by gender.
The sample exhibited homogeneity in terms of experiencing repeated violence, which had been reported to the police by the victims and had also initiated a legal process against the perpetrators. Participation in therapeutic interventions was mandated by the Prosecutor’s Office, in accordance with Article 11 of Law 3500/2006, with the participants’ consent to attend a counselling program at the Family Therapy Clinic of HST. Inclusion criteria for the research included cohabitation of the couple for a period exceeding one year, age over 25 years, and non-participation in parallel violence therapy. Purposive sampling was conducted to ensure the conditions above. The sample size was also determined based on the available cases reported to the Prosecutor’s Office during the specific period.
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Table 2. Sample sociodemographic characteristics.
4. Material and Method
A mixed-method approach was used for data collection. Two questionnaires were used to collect quantitative data, administered at the beginning and end of the interventions and one year after completion, to assess the duration of the results (feedback). Conflict tactics were explored using the Revised Conflict Tactics Scale (CTS2). The scale was adapted for the Greek sample (Kalaitzaki et al., 2010) . Two subscales were utilised in this research: 1) physical assault and 2) injury/harm. These subscales provided information on the perpetration and victimisation of both individuals, including frequency, variety of behaviours, and form.
Emotions closely associated with relationships and the properties (behaviour) of the couple members (Paritsis, 2010, 2020, 2022) were measured using the Differential Emotions Scale-modified (DES.MOD). Galanakis et al. (2016) validated the scale for the Greek sample. The DES.MOD scale aims to assess the degree of experiencing positive and negative emotions in the past fifteen days (Fredrickson, Tugade, Waugh & Larkin, 2003; Stalikas et al., 2012) .
Therapeutic intervention
The therapeutic interventions for the nine violent couples were conducted separately for each couple during the same period (Spring 2021), with sessions held every 15 days. There was no predetermined number of sessions, ranging from 5 to 9. A total of 53 therapy sessions were conducted for the nine cases by four therapists trained at HST.
The therapeutic intervention process was based on the Therapy Manual of the HST (Paritsis, 2021) .
During sessions, specific techniques were used a priori in the first session, specifically techniques that create a sense of relaxation and acceptance, remove potential resistance, facilitate the formation of a therapeutic relationship (joining), increase trust, and evoke positive emotions. Examples of these techniques include Overpositive Descriptions, Expressions of Congratulations/Admiration, and Reframing. In each case in the research, Reframing of the complaint was performed to promote therapeutic benefits and increase safety. Additionally, systemic-circular questions were utilised in each session, and a Genogram was constructed for each member of the couple (McGoldrick & Gerson, 1999; von Schlippe & Schweitzer, 2008; Papadioti-Athanasiou & Softa-Nall, 2012) .
In the subsequent sessions, various techniques were employed, such as Position Description on a general level, Similar Stories, Appeal to Authority, and paradoxical techniques like Therapeutic Alchemy, Provocative Therapy, and Assignments (Paritsis, 2010, 2020, 2012, 2022; von Schlippe & Schweitzer, 2008) . The five specialised techniques for couples played a significant role (Paritsis, 2022) . The beginning and end of each session included an assessment of the changes during the previous period, the therapeutic relationship, and the intervention.
HST does not use specific techniques in the intermediate stages of the intervention or for each couple by default. The techniques used vary according to the specific issues the therapist needs to address in each session and the effectiveness of each intervention. For example, in a couple where most of their problems are related to an external person, such as the parent of one member of the couple, Reframing and Therapeutic Alchemy are often used. In another case, when there are many frequent critical comments between partners (for example due to responsibility for the failure of an investment caused by one member of the couple), then a special couple technique can be used, in which each member is asked to describe the positive characteristics of the other. This technique can be combined with the therapist’s Superlative Descriptions of the individual and the couple, Reframing and some paradoxical techniques.
Statistical analysis
Quantitative variables were expressed as mean values (Standard Deviation) and as median (interquantile range), while qualitative variables were expressed as absolute and relative frequencies. Cochran’s Q tests were used for evaluating the changes in the proportions throughout the follow-up period. Repeated measures ANOVA were used for evaluating the changes in participant’s positive and negative feeling throughout the follow-up period. Bonferroni correction was used in order to control for type I error. In positive and negative feelings scales, the effect sizes of the time differences were also computed. For examining the differences in the CTS-2 scores, Wilcoxon sign tests were used. All reported p values are two-tailed. Statistical significance was set at p < 0.05 and analyses were conducted using SPSS statistical software (version 26.0).
5. Results
Sample initially consisted by 10 couples, whose characteristics are presented in Table 2, by gender. Mean women’s age was 42.8 years (SD = 14.3 years) and mean men’s age was 47 years (SD = 13.8 years). Almost all couples (90%) had children and the majority were living in an urban place (70%) and were Greeks (70%). The majority of women (40%) were high school graduates, while the majority of men (30%) were middle school graduates. Most men (90%) and women (70%) worked in a permanent basis.
Changes in women’s CTS2 scores regarding physical assault and injury are presented in Table 3. Throughout the follow up period the percentages of female-to-male physical assault changed significantly. More specifically, the percentage of female perpetration regarding female-to-male physical assault, after Bonferroni correction, were similar in pre and post measurements (p > 0.05), however the scores reduced significantly. Similarly, the percentage of male victimization regarding female-to-male physical assault were similar in pre and post measurements (p > 0.05), however the scores reduced significantly. The percentages of female perpetration or male victimization regarding female-to-male physical assault at 1 year after reduced significantly in comparison to just after the intervention (p = 0.008 for both comparisons). For mild and severe female
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Table 3. Changes in women’s CTS2 scores regarding physical assault and injury.
Note. In cases where no assault or injury occurred, scores were not computed 1p-value for changes throughout follow-up period; +Cochran’s Q test; ++Wilcoxon sign test.
perpetration regarding female-to-male physical assault no significant changes were found in both percentages (p > 0.05) and scores. On the contrary, in both mild (p = 0.016) and severe (p = 0.008) male victimization regarding female-to-male physical assault significant differences were found in the pre-post scores and in the percentages at 1 year compared to the ones after the intervention. No female-to-male injury was recorded.
Changes in men’s CTS2 scores regarding physical assault and injury are presented in Table 4. Throughout the follow up period the percentages of male-to-female physical assault changed significantly. More specifically, the percentage
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Table 4. Changes in men’s CTS2 scores regarding physical assault and injury.
Note. In cases where no assault or injury occurred, scores were not computed 1p-value for changes throughout follow-up period; +Cochran’s Q test; ++Wilcoxon sign test.
of male perpetration regarding male-to-female physical assault, after Bonferroni correction, were similar in pre and post measurements (p > 0.05), however the scores reduced significantly. Similarly, the percentages of female victimization regarding male-to-female physical assault were similar in pre and post measurements as well as their scores (p > 0.05) (Table 5). The percentages of male perpetration or female victimization regarding male-to-female physical assault at 1 year after reduced significantly in comparison to just after the intervention (p = 0.031 for both comparisons). For mild and severe male perpetration and female victimization regarding female-to-male physical assault no significant changes were found in both percentages and scores (p > 0.05). No female-to-male injury was recorded.
Significant changes were found in both positive and negative feelings scores throughout the follow up period (Table 5). More specifically, after Bonferroni correction it was found that positive feelings were significantly greater after the intervention in both men and women compared to before the intervention (p = 0.003 and p = 0.001 respectively). Also, at 1 year after the intervention, both men and women had significantly more positive feelings than just after the intervention (p = 0.002 and p = 0.004 respectively). On the other hand, participants’ negative feelings reduced significantly after the intervention compared to before (p = 0.001 for men and p = 0.006 for women). Furthermore, only in women negative feelings increased significantly at 1 year, compared to just after the intervention (p = 0.024). Even though both negative and positive feelings increased at 1 year after, judging by their effect sizes, the increase of the positive feelings was greater.
The statistical results of the research, after comparing the data at three different times, before the intervention, after the intervention and one year after the completion, show changes in the relationships between the members of the couple, in the behaviors between them and in their mutual emotions. These changes are in a positive direction compared to the period before the interventions and concern men and women, who experienced either unilateral violence or mutual violence.
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Table 5. Changes in participants’ positive and negative feelings.
1p-value from repeated measures ANOVA; 2p-value (after Bonferroni correction) and effect size for pre vs post comparison from pairwise comparisons; 3p-value (after Bonferroni correction) and effect size for post vs 1 year comparison from pairwise comparisons.
6. Discussion
The pilot study provided indications that support the effectiveness of the intervention through HST in improving/reducing aggression and eradicating intimate partner violence. No incidents of violence occurred during the intervention or within one year after its completion, indicating the durability of the intervention’s effects. While no differences were observed before and after the intervention in terms of perpetration (W-M) and victimisation of women (M-W) regarding physical assault, a significant reduction was observed in the frequency and types of violent behaviours committed by women towards men, as well as in the experiences of women from their partners. There is a reciprocal nature in the aggression, which does not absolve the perpetrator but instead reinforces the vicious circle of violence and aligns with Swan et al. (2008) , perspectives on female aggression. In two cases, mutual violence was apparent.
These findings provide indications due to the design of the research. They are of interest, as in the field of systemic therapy, there seems to be a lack of therapeutic models specifically addressing violence in couples and lacking sufficient evidence (Stephenson et al., 2016; Sexton et al., 2011; Zimmerman et al., 1997) .
To our knowledge, in a research therapy on intimate partner violence, a modified model of SFBT was applied in individual and group-couple therapy. It was found that couples who received SFBT therapy experienced 27 times less damage compared to data from other studies, and there was less recidivism among the perpetrators after six months for those who received group-couple therapy. Another finding is that this model is unsuitable for every form of intimate partner violence but only in combination with other interventions after evaluation. A six-week gender-specific anger management psychoeducation program precedes the conjoined therapy for couples. The same model effectively reduced aggression and increased partner satisfaction (Stith et al., 2005, 2011) . In the same research, it was noted that for the treatment of violent couples in some cases (when there are limitations that prevent therapists from continuing with an SFBT orientation), the therapist needs to be more directive and instructive than the SFBT model describes, moving from a collaborative non-directive stance. This finding supports the epistemological positions of the HST regarding the role of the therapist in relation to the non-participating observer/non-expert that SFBT and other models advocate.
The effectiveness of SFBT in therapy for non-violent couples was shown in the increase in relationship satisfaction (Zimmerman et al., 1997; Nelson & Kelley, 2001) . Additionally, other relationship characteristics such as couple cohesion and consent (Zimmerman et al., 1997) , relational skills, and an increase in self-esteem among the perpetrators (in group therapy) (Lee & Sebold, 2004) are among the positive outcomes of applying the model in terms of emotions and characteristics of the couple relationship.
EFT, in turn, has to show significant effectiveness in increasing satisfaction in non-violent couples’ relationships. To our knowledge, recent findings regarding the effective application of EFT in the therapy of intimate partner violence come from a case study (Slootmaeckers & Migerode, 2019) . The application focused only on the first stage of EFT, the cycle of de-escalation, where couples understand the negative interaction cycle that causes distress in their relationship. This was an initial indication that under specific conditions, EFT can effectively help reduce intimate partner violence in cases of situational violence following an assessment for acceptance in therapy. The application of EFT in non-violent couples shows significant effectiveness in increasing partner satisfaction and in the long-lasting nature of the results, including other individual and relational characteristics (Beasley & Ager, 2019; Wiebe & Johnson, 2016; Wiebe et al., 2016, 2017) .
The second finding of this pilot study is the increase in positive emotions of one partner towards the other and the corresponding decrease in negative emotions. Improvement in emotions and other relationship characteristics has been previously observed in both SFBT and EFT. This finding seems to confirm the scientific principles of the HST, which is based on medical science, regarding the impact of relationships on emotions (and behaviour) since emotions and behaviour change within the context of relationships through circular causality in brain function. The behaviour of cells in certain parts of the brain forms neural networks that determine emotions, thoughts, and behaviour (brain functions). The emerging properties, i.e., differentiated thoughts, emotions, and behaviours through psychotherapy (effective interventions), recursively influence and modify the neural network itself (Paritsis, 2003) . In the HST, intervention in relationships, through the various techniques (operating in the unconscious) used by the model, aims to enhance emerging properties and ultimately modify the patterns of relationships, i.e., the way of relating.
A third finding of this pilot study pertains to the therapeutic process in cases where SFBT and EFT were applied to violent couples. There are differences compared to HST in terms of the conditions for participation in the therapy, the appropriate type of therapy (individual and conjoint couple therapy), and the suitability regarding the form of violence. Based on the pilot research, HST shows indications that it can intervene without the constraints of SFBT and EFT, specifically to exclude couples and treatment solely for situational violence. Specifically, all the couples in the study did not experience what is characterised as common/situational violence, and HST did not exclude any couples whose prosecutorial description of the case indicated different duration, frequency, and intensity of violence by the perpetrator. Additionally, the safety concern that leads other models to separate treatment of offenders and victims or to non-participation in therapy without prior intervention was addressed by HST within the conjoint therapy of partners using the techniques of the model. Of course, this issue is sensitive and remains open for evaluation.
Another general finding of the pilot study concerns the perpetrators, all men. The victims were their female partners who reported the violence, but mutual violence was reported in two cases. The finding regarding male perpetrators is consistent with national and European statistics that have been presented. Regarding Greece and the region where the research was conducted, possible interpretations include the dominant culture that often reinforces the manifestation of violence, the social identities of both genders and the delayed or absent seeking of help from mental health professionals at the individual and relational dysfunctions.
Based on the above findings regarding epistemology, intervention, degree, and type of effectiveness, there are strong indications that the HST model is suitable for treating violent couples that exhibit the characteristics of the sample in this pilot study.
This research showed that in the field of systemic there can be effective therapy in violent couples, through intervention in their relationships with the HST model, without exclusion, assessment and conditions of acceptance in therapy. Therapeutic interventions through HST seem to lead to the eradication of IPV, to the qualitative coexistence of partners (due to positive changes in the level of behavior and emotions between them) and that these effects last. These findings, as well as the observations made about the epistemology and therapeutic practice of HST, can contribute as a new proposal, to the open dialogue for more effective models for IPV and beyond systemic epistemology, in the context of mixed models of therapy for IPV where individual-intrapsychic interventions meet relational-interpersonal ones.
This research was pilot in nature and subjected to limitations. The sampling and the available cases of the Prosecutor’s Office during the specific time period, do not allow the generalization of the results to the general population. For the reliability of the results, due to the difficulty of creating a control group, a mixed method of data collection was applied, feedback was requested from the couples over a period of one year after the end of the intervention, four HST trainees and experienced therapists intervened as well as an external supervision team participated in the research. Couples’ participation in treatment after prosecutorial referral may have influenced intervention outcomes due to secondary benefits on the part of perpetrators. Applying the model to couples who come voluntarily could potentially differentiate the results. In addition, important factors related to the implementation of the interventions, such as frequency, therapist profiles, etc., could have influenced the results. Further investigation of the model in a larger sample, in different socio-cultural and geographic contexts, with heterosexual or same-sex partners, and using different therapeutic contexts, is necessary to conclude the effectiveness of the model.