Introduction

Intimate partner violence (IPV) is a public health concern, so the better we understand it, the more effective interventions will be (Romero-Martínez et al. 2019a, b). Literature has pointed to high rates of IPV perpetration (European Agency for Fundamental Rights [FRA] 2014; World Health Organization [WHO] 2021) and recidivism worldwide (Petersson and Strand 2017), even after informal, such as ordering perpetrators to intervention programs (e.g., Arce et al. 2020), or formal interventions, such as arrest or civil protection orders (Broidy et al. 2016; Cordier et al. 2019).

During 2022, in Portugal, 26,073 IPV cases were reported to the authorities. Portuguese official statistics revealed that IPV is the second most reported crime, with evidence showing a continuous growth throughout the years (Internal Security System [ISS] 2023; Directorate-General for Reintegration and Prison Services [DGRSP] 2020; Safe Communities Portugal 2022). Although data regarding recidivism are scarce, a recent study conducted in Portugal with men convicted both to prison and community orders found a general recidivism rate of 44.4% and an IPV recidivism rate of 12.4% among IPV perpetrators (Cunha et al. 2021). As such, it is essential to develop intervention programmes that effectively promote changes in perpetrators’ beliefs and behaviours to reduce the risk of recidivism and the prevalence of this crime and positively reintegrate the perpetrators into society (Gonçalves et al. 2020). Thus, a greater focus on the needs of each individual, criminogenic needs, and level of risk, will provide better results (Akoensi et al. 2013; Cunha and Gonçalves 2013).

Despite the high and rapid proliferation of intervention programmes for IPV perpetrators, the results regarding their effectiveness remain controversial, not only because of the relatively high rates of post-intervention recidivism but also because of the high dropout rates (Capinha et al. 2020; Cunha et al. 2022; Devereux 2009). An element that has been identified in the literature as associated with low effectiveness of the intervention is motivation for change. Thus, it is important not to neglect motivational work with IPV perpetrators. Motivational Interviewing (MI) has demonstrated to be an effective method in working with this population, allowing the individuals to explore and resolve ambivalence toward change (Cunha et al. 2023a, b; Cunha and Caridade 2023; Gonçalves et al. 2020). However, in the absence of this motivation, a barrier is created to the potential development of behaviour and attitudinal change. When working with perpetrators, it is necessary to consider two factors: the agreement (or not) in participating in the programme, and their intrinsic motivation. It is essential that perpetrators agree to participate in the programme, otherwise they will create resistance, thus preventing any progress. Intrinsic motivation for collaboration and commitment to the programme is a factor of equal importance because if it does not exist, it will be difficult to take any benefits from the intervention (Devereux 2009).

IPV Perpetrators Motivational Interviewing

MI is a person-centred counselling style to promote an individual’s involvement in treatment and increase motivation for change, addressing the common problem of ambivalence about change (Miller and Rollnick 2013; Cunha 2016). This approach begins with establishing a collaborative therapeutic alliance/rapport (Vallano et al. 2015). MI is often associated and confused with the transtheoretical model (TTM) of change of Prochaska et al. (1992). MI is not a comprehensive theory of change and the TTM is not an essential part of MI. However, MI and TTM are compatible and complementary (Miller and Rollnick 2013). TTM assumes that, until achieving change, all individuals go through a series of stages: i) pre-contemplation; ii) contemplation; iii) preparation for action; iv) action; and v) maintenance. In this way, the therapist helps the client progress through these stages towards the change, and, simultaneously, the individual changes behaviour (Cunha 2016). Throughout the progression between the different stages, positive changes become more stable and internalized. However, effective strategies for one phase may not be effective for another phase and may even be counterproductive (Wong et al. 2007).

MI is regulated by four basic processes: engaging, focusing, evoking, and planning. It comprises a respectful evoking of the individual’s motivation, knowledge, and acceptance, recognizing that whether change happens depends on each person’s choice (Miller and Rollnick 2013). The use of MI is particularly well-suited to individuals in the pre-contemplation or contemplation stages of change, since they are still reluctant at this respect (Austin et al. 2011; Soleymani et al. 2018). By using MI, individuals are allowed to explore the pros and cons inherent to making changes and work to resolve their ambivalence towards behaviour change (Farbring and Johnson 2008).

Several studies have investigated the effectiveness of MI with perpetrators of IPV. For example, Soleymani et al. (2018) reviewed studies assessing the effectiveness of MI as a pre-treatment intervention to promote commitment to treatment for men referred to perpetrators’ intervention programmes (PIPs). The authors analysed whether the five studies they reviewed included MI and whether MI consider the motivation for changing behaviour, as well additional factors that might influence engagement in treatment. Soleymani et al. (2018) concluded that MI could have positive effects on commitment to interventions for IPV perpetrators. A meta-analysis conducted by McMurran (2009) aimed to systematically review the impact of MI on offender populations. The study established that MI’s effectiveness is frequently assessed with substance abuse by perpetrators. However, other situations, such as IPV perpetrators, drunk drivers, and general perpetrators, have also been assessed. The results of this meta-analysis indicated that MI is used with three main purposes in mind: i) to enhance retention and engagement in treatment; ii) to improve motivation for change; and iii) to change behaviour and reduced offending (McMurran 2009). More recently, Santirso et al. (2020) conducted a meta-analysis and Pinto e Silva et al. (2022) a systematic review that assessed interventions' effectiveness for IPV perpetrators that included MI. The results indicated that IPV interventions incorporating MI were significantly more effective in increasing the intervention dose and reducing dropout, than interventions without MI.

The Short Motivational Programme (SMP) is a manual constructed from the theoretical basis and principles of MI, incorporating cognitive-behavioural tasks, and applying them from this approach (Austin et al. 2011). The objective of the programme is to stimulate offenders to the "action" phase of change (Devereux 2009), increasing their motivation so that, when they return to freedom, they seek social and community resources in order to solve their rehabilitative needs (Austin et al. 2011). The intervention also involves helping offenders understand how their cognitions, emotions, and decision-making have affected their delinquent behaviour, thereby maintaining the principles of prison rehabilitation programmes (Bonta and Andrews 2017).

The SMP was initially developed between 2001 and 2003 by Brendon Anstiss, a psychologist at the New Zealand Department of Correction. The original SMP was revised in 2017 and the revised version was released in September of that same year. The SMP underwent language changes by replacing, for example, "offender” by "participant", therefore creating a more flexible approach and a relationship between the participant and the therapist (Best 2019). The SMP is a low-intensity programme, and it is typically used with medium-risk perpetrators, although it has also been used with high-risk perpetrators serving short prison sentences and with low-risk perpetrators in case their motivation for change is not at an appropriate level for the occurrence of change (Austin et al. 2011).

Austin et al. (2011) assessed the effectiveness of SMP with a sample of 38 high-risk male perpetrators aged 18 to 42 years serving short sentences. The results of their study demonstrated an increase in motivation for change of perpetrators from the pre-test moment to the post-test, with stability in this change three to 12 months after the application of the SMP.

Current Study

Given the conflicting results of the effectiveness of PIPs (Park and Kim 2022; Travers et al. 2021) combined with the importance to consider other techniques to improve their effectiveness (Santirso et al. 2020; Pinto e Silva et al. 2022; Aaron and Beaulaurier 2016), SMP emerges as an important tool in this field. Furthermore, research suggests that integrating MI into IPV interventions promotes the effectiveness of PIPs evidence (e.g., Cunha et al. 2023a, b; Santirso et al. 2020; Pinto e Silva et al. 2022). Given the importance of incorporating MI in interventions with IPV perpetrators and the scarcity of studies in the Portuguese context focusing on this area, the current study, therefore, aimed to determine the short-term effects of the SMP in increasing the motivation to change in a sample of Portuguese IPV perpetrators sentenced to prison and to analyse its suitability and acceptability.

Methods

Participants

Inclusion criteria are: being men over 18 years old sentenced to prison for domestic violence crimes against a female intimate partner. The existence of severe psychopathology, personality disorder and cognitive deficits were defined as exclusion criteria. The inclusion and exclusion criteria were assessed in a first moment through the analysis of the perpetrators’ individual files available in the prison and then through an intake interview with each potential participant.

The sample consisted of 10 men aged between 26 and 64 years (M = 47.8; SD = 13.2). Most participants were divorced/separated (60%) and concluded the elementary education level (n = 5; 50%). All participants resided in the North of Portugal. Participants are identified by numbers—from 1 to 10—to safeguard their identity (Table 1).

Table 1 Sociodemographic and juridical characteristics of the sample
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Procedures

To adapt the SMP to the Portuguese population, a translation and back-translation process was conducted. More specifically, the SMP was first translated from English into Portuguese by two researchers who are native Portuguese speakers and fluent in English. This was followed by the translation of the Portuguese version into English by two independent researchers fluent in Portuguese and English. Inconsistencies were revised to eliminate possible semantic differences between the English and Portuguese versions of SMP. This version was then revised by two expert researchers in the field.

In order to carry out the study, permission to collect data was obtained from the Directorate General of Reintegration and Prison Services (DGRSP). Through the perpetrators’ individual files analysis, 20 individuals who met the previously mentioned inclusion criteria were identified. The potential participants were then approached and individually interviewed to obtain their consent to participate in the study and assessed for eligibility. After a detailed explanation of the investigation and clarification of any doubts, ten perpetrators agreed to participate in the study and gave their written consent. At intake, participants fulfilled a set of psychological measures, as well as at the end of the intervention, in order to assess the intervention effectiveness. The ten participants who refused to participate cited time incompatibility (conflict with their work and/or studies in prison) as the main reason for not being able to participate in the SMP.

The five sessions of SMP were held over three months and took place in one male prison in the North of Portugal, lasting between 45 min to one hour each. In each session, short individual interviews were conducted to explore the acceptability and suitability of the SMP, as well as the experiences of the participants. The programme was conducted by a psychologist with training in intervention with perpetrators and in the SMP.

Ethical procedures regarding privacy and data protection established by the Portuguese legislation and the Declaration of Helsinki (2013) were ensured. The study was approved by the Ethics Committee of the University hosting the study.

Measures

The Attitudes Towards Marital Violence Scale (ECVC) (Machado et al. 2007) is a 25-item measure to assess attitudes towards IPV. It is scored on a 5-point scale, ranging from 1 (completely disagree) to 5 (completely agree), comprising four factors: Legitimation and Minimization of Minor Violence, Legitimation of Violence due to Women’s Behaviour, Legitimation of Violence due to External Causes, and Legitimation of Violence due to Family Privacy. A higher score translates into attitudes supporting IPV. ECVC has good psychometric properties, with correlations between each factor and the total score varying between 0.34 and 0.71, and internal consistency for the total score of 0.93. In this study, the internal consistency for the total scale was 0.94 at the pre-test and 0.94 at post-test. Among the instrument's factors, internal consistency ranged from 0.88 to 0.92 in the pre-test and 0.80 to 0.92 in the post-test.

The Levenson’s Self-Report Psychopathy Scale (LSRP) (Levenson et al. 1995; Portuguese version Coelho et al. 2010) consists of 26 items divided into two separate scales: Primary and Secondary Psychopathy. Items are rated in a 4-point Likert-type scale, varying from 1 (strongly disagree) to 5 (totally agree), and the final score, results from the sum of each item. The original instrument (Levenson et al. 1995) had a satisfactory internal consistency. The Portuguese version (Coelho et al. 2010) is composed of 19 items and also reached good internal consistency values. In the present sample, the instrument showed an internal consistency of 0.58 and 0.61, for Primary and Secondary Psychopathy, respectively, on the pre-test. For the post-test, the internal consistency was of 0.81 and 0.80. The internal consistency for the total scale was 0.78 and 0.88 for the pre-test and post-test, respectively.

The Spousal Abuse Risk Assessment (SARA) (Kropp et al. 1998; Portuguese version Almeida and Soeiro 2010) comprises 20 risk factors organized into two parts: Part 1 (Criminal History and Psychosocial Adjustment) is related to violence risk in general, and Part 2 (History of Domestic Violence) is related to the risk of spousal violence. The presence of individual risk factors is coded on a 3-point Likert-type scale (0 = absent, 1 = possibly or partially present, 2 = present). Statistical analyses indicated moderate levels of internal consistency (Kropp and Gibas 2020). In the present sample, internal consistency for the total scale was 0.52 at pre-test and 0.69 at post-test. For Part 1, the instrument showed an internal consistency of 0.90 at pre-test and 0.66 at post-test. For Part 2, the internal consistency was 0.70 at pre-test and 0.76 at post-test.

A sociodemographic and juridical questionnaire was completed at intake, to obtain data related to age, city of residence, marital status, educational qualifications, victim (i.e., wife, ex-wife, girlfriend), type(s) of violence committed against the intimate partner, and number of convictions.

Intervention

The training programme was based on the SMP, which consists of five sessions divided as follows:

Session 1

Involvement and Assessment of Rehabilitative Needs: this is part of the process of developing a relationship between the therapist and the participant, that is, the promotion of rapport. This process is performed before the therapist's intervention regarding the exploration of the factors that led the participant to delinquent behaviour. After verifying these factors, the session takes place with the objective of exploring each one and how they impacted the behaviour and decisions made by the participant.

Session 2

Find Focus—Crime Map: The individual should reflect on the factors identified in the first session and link them to the themes on the Crime Map to gain greater knowledge and awareness of how these factors led to offending and consequently to their conviction. The content of this session allows the individual to recognise the problem and to establish a focus for the rest of the programme. This activity consists of describing and developing awareness of the build-up to the offence, including thoughts, feelings, actions, and levels of intoxication.

Session 3

Evoke Motivation for Change—Consequences, Values and Needs: The participant is allowed to reflect on the consequences of the perpetrated crime, analyse whether this behaviour is consistent with personal values, and consider how delinquency impacts basic needs.

Session 4

Strengthen the Commitment to Change—Temporal Projection: This activity aims to identify the long-term consequences of changing or maintaining the participant's current lifestyle and to increase commitment to change through time projection. The participant is asked to consider their ideal future, their hopes, and dreams, and to reflect on their preferred life in 5–10 years. The participant is then asked to describe their life in 5–10 years if they do not make any changes and continue with their current lifestyle. In the end, both paths are shown, and the therapist should help the participant to reflect on the possible futures.

Session 5

Change plan: This activity aims to strengthen commitment to change by developing and sharing goals. The participant needs to complete and share a 'change plan', highlighting goals and an action plan to address their rehabilitation needs. Finally, the participant can share the plan with people who are important in their life.

Data Analysis

Within-group analysis using paired samples t-tests were performed to determine the change between pre- (baseline) and post-test (post-intervention) using SPSS version 29. As this is a feasibility study and the sample size was small, effectiveness was examined using p-values, as well as Hedges’ g effect sizes. Hedges’ g scores of 0.2 demonstrate small changes, scores of 0.5 represent medium changes, and scores of 0.8 represent large changes (Lakens 2013).

In order to analyse the relation between the sociodemographic and juridical variables, the results of the instruments at pre- and post-test and change scores, Pearson, Spearman and Point-Biserial Correlations and Chi-Square tests were carried out.

The Reliable Change Index (RCI; Jacobson and Truax 1991) was used to assess the intra-subject clinical change. RCI is an index that ensures very high reliability (Atkins et al. 2005), providing information about treatment effects for each individual identifying whether an individual improves or declines in comparison to the baseline assessment (Conboy 2012). Values greater than 0.84 suggest that a reliable or significant change occurred. Results lower than -0.84 mean that deterioration has occurred (Wise 2004). In this study, three categories of RCI were defined, following Brazão et al. (2015): “global improvement” (GI)—values greater than 0.84; “global deterioration” (GD) – values lowest than -0.84; and “no change” (NC) – values between -0.84 and 0.84.

Interviews conducted over the five SMP sessions were used to explore the acceptability and appropriateness of the SMP, as well as the experiences of SMP participants. All interviews were audio-recorded and fully transcribed. Each transcript was read by the responsible researcher for initial understanding, and a content analysis was used to analyse the data. Expressions were selected from the text and categorised and the number of participants who mentioned a particular phrase was then counted. Content analysis was used to synthesise and interpret the expressions used by the participants.

Results

SMP Short-Term Effects

Within-Group t-Test of Changes

At pre and post-test, the participants presented high levels of attitudes supportive of IPV (Table 2), with average values ranging from 99.6 to 96.5. Participants’ pre-test minimum scores ranged between 41 and 178. In the post-test, participants’ scores varied between 49 and 147. Despite the decreases especially at the maximum value, no statistically significant differences were observed between pre- and post-test, neither in the total score or in the four factors (Table 2).

Table 2 Differences in attitudes supportive of IPV, psychopathy and IPV risk
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For the scores obtained on the Levenson Scale, analysing the values for the primary factor referring to features such as manipulation, envy, insensitivity and indifference, no differences were found from pre- to post-test. The same happened in the secondary factor, associated with impulsivity and behavioural control, as not statistically differences were found between the two moments (Table 2).

Regarding IPV recidivism risk, participants’ scores were generally low, both at pre- and post-test. However, results revealed statistically significant differences between pre- and post-test in total risk, t(9) = 6.328, p < 0.001, in Part 1 (i.e., criminal history and psychosocial adjustment), t(9) = 3.881, p = 0.004, and in Part 2 (i.e., history of domestic violence), t(9) = 4.311, p = 0.002, with large effect sizes (Table 2). Participants revealed lower scores at post-test.

Clinical Change in Attitudes Supportive of IPV and Psychopathy after SMP Completion

Data relating to clinical change in attitudes towards IPV and psychopathy after SMP completion are displayed in Table 3. On overall attitudes towards IPV, the results revealed that the most part of the participants showed a global improvement (GI; n = 6), while three presented a global deterioration (GD). When the different factors were analysed separately, factor 1 (n = 4) and factor 2 (n = 4) were those who revealed the highest number of participants with global improvements, although the similar number of participants with no changes. Factor 3 (n = 5) and factor 4 (n = 4) revealed an opposite pattern, i.e., participants with global deterioration represented the highest group.

Table 3 Reliable Clinical Change for Attitudes Towards IPV and Psychopathy
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Regarding psychopathy, a highest number of participants revealed global improvement after SMP completion in Factor 1 (n = 6), while in Factor 2 the highest number of participants did not reach clinical change (NC; n = 6). The number of participants with global deterioration was residual (1 for Factor 1 and 2 for Factor 2).

Correlations among Sociodemographic and Juridical Variables and Outcome Variables

In order to analyse the relation between the sociodemographic and juridical variables, different correlation and association tests were performed (cf. Table 4).

Table 4 Correlations among sociodemographic variables and pre and post-test variables
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At pre-test, a statistically significant negative correlation was found between educational level and attitudes supportive of IPV (rs = -0.890, p < 0.01), suggesting that the higher the level of education of the participants, the lower the presence of attitudes supportive of IPV. There was also a statistically significant negative correlation between stalking and attitudes supportive of IPV, specifically legitimation of violence due to family privacy (rpb = -0.700, p < 0.05), meaning that individuals who stalk their intimate partner presented lower levels of legitimisation of violence through appeals to the concept of privacy and the need to protect families from outside interference.

At post-test, there were also found statistically significant negative correlations between educational level and attitudes supportive of IPV (rs = -0.650, p < 0.05 for Factor 2, rs = -0.814, p < 0.01 for Factor 3 and rs = -0.693, p < 0.05 for Factor 4), with individuals revealing higher education levels showing less attitudes supportive of IPV. Regarding stalking perpetration and attitudes supportive of IPV, there were also two more statistically significant negative correlations found. First, there was a relation between stalking and legitimation of violence due to external causes (rpb = -0.831, p < 0.01) and, as in the pre-test, between stalking and legitimation of violence due to family privacy (rpb = -0.680, p < 0.05). These correlations suggest that stalking behaviors are associated with lower levels of legitimisation of violence as a result of external factors (alcohol, unemployment, drugs, economic difficulties, extramarital affairs).

Regarding clinical change, no statistically significant correlations were found (see Supplementary files).

SMP Suitability and Acceptability

From the interviews content analysis three main categories were identified: Crime perceptions and its consequences; Expectations and plans for the future; and Change plan (see Table 5).

Table 5 Categorization system of the interviews inherent to the SMP
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Crime Perceptions and its Consequences

When asked about the motives underlying their crime, six participants described emotional uncontrol as the main reason (e.g., "I saw everything black, I got out of control, it had never happened to me.”- P9); while three attributed the crime to alcohol consumption (e.g., “I drank a lot. I got to the point where I needed alcohol to be able to write my name.”- P4) and one to substance use (e.g., “We had ugly arguments about the drugs.” – P7). In this sense, seven participants reported having felt the need to work on their emotions, with a view to better controlling them (e.g., “I was very impulsive, I did not even think. I had to change that.”—P1).

Regarding the crime, all participants expressed regret, recognizing the seriousness of their conduct (e.g., “I did not know insults would send me to jail, but now I understand why. (…) I hurt her a lot, I know I did. She did not deserve it.”—P4).

As the main consequences of criminal conduct, participants alluded to being away from their children (n = 4) (e.g., “It’s hard to be away from my kids.”- P1) and the prison environment (n = 7) (e.g., “I can't take it anymore.”—P5). However, despite these negative aspects, seven participants described their conviction and stay in prison as a moment of re-flection—“a salvation” -, because they had the opportunity to carry out detoxification treatments and cessation of alcohol and substance use (e.g., “If I hadn't come to prison, I’d either walk around alone or I’d be dead.”; “My ex did what was best. Coming to prison was a salvation, I managed to treat myself. Otherwise, I would be dead.”—P4).

Expectations and Plans for the Future

When asked about their goals, dreams, expectations, and plans for the future, the most common answers were related to family and work issues, thus demonstrating the growing importance of these factors in the lives of the participants.

Regarding family issues, the answers focused on family closeness (n = 9) (e.g., “I want to resume my relationship with my son”—P5), whether it was with their children, a companion, and/or the parents; however, relating to labour issues, three different types of response can be verified: maintenance and/or professional progression (n = 8) (e.g., “I want to go back to work in my area.”- P2), professional training (n = 3) (e.g., “I'd like to learn more.”—P6), building their own business (n = 2) (e.g., “One of my goals is, one day, to open my restaurant.”—P3) and work abroad (n = 1) (e.g., “When I get out of here, I am going to Switzerland to work. I have been there a long time and I want to go back.”—P2). However, they also reported a general interest in the search for financial stability (n = 8) (e.g., “I want to be stable. Having my own house so I can have my kids there.”—P7) and emotional stability (n = 7) (e.g., “I have to think before I act. I want to be a better person and I know I am going to make it.”- P1), so as to achieve the desired objectives.

Change Plan

Concerning the changes to be made, several were identified by the participants, either changes that have already been made and intend to maintain or that they still want to accomplish. The most mentioned were: i) the need for greater emotional control, including greater weighting and reduction of impulsiveness (n = 9) (e.g., “I have to take it easy, think long and hard before I act.”—P8); ii) the desire to reduce or maintain the absence of alcohol consumption (n = 7) (e.g., “Alcohol ruined me, I'm not going back to the same.”- P4), iii) maintain favourable interpersonal relationships (n = 3) (e.g., “We could stay a long time without consuming, but then one of our friends would call us and encourage us to do drugs and we wouldn't say no. I have to get away from these people.”—P7), iv) avoid antisocial environments (n = 2) (e.g., “I have to avoid places that influence me and make me go back to the same.” – P10), and the v) total abandonment of substance use (n = 1) (e.g., “Both my girlfriend and I underwent treatment. We can no longer consume for the good of our children.”—P7).

About the motivations for change, the main reason for participants to want to make the previously mentioned changes was by personal evolution (n = 8) (e.g., “I really want to change so I can improve my life.”—P7), enhancing a great desire to want to improve and be better people. However, other motivations for the existence of these changes were also mentioned: i) family (n = 3) (e.g., “I want my happiness. I want to be happy with my family and that they accept me, just as I am.”—P6); ii) children (n = 2) (e.g., “I want to make these changes for myself, for my family and especially for my children, for all the people who believe in me and who like me.”—P7); iii) repentance (n = 2) (e.g., “The reason I want to make those changes in my life is due to the situations I've caused (…) I want to be better than I was.”—P8); and iv) prevent criminal recidivism (n = 1) (e.g., “In case there is a relapse, I have to get help. (…) I must be true to my past.”—P10).

Only one factor has been identified as preventing the intended changes from being accomplished: fear of social discrimination. Few participants mentioned fears about their reintegration into society, however, those who did so expressed concern that there was a fear of discrimination on the part of the general population (n = 4) (e.g., “I'm afraid of the label I can carry.”; “Fear of society doing some discrimination and not helping in my development.”; “I'm afraid of what they might think about me.”—P3).

Discussion

The current study aimed to investigate the short-term effects of the SMP in increase motivation to change in a sample of IPV perpetrators sentenced to prison and explore the suitability and acceptability of the SMP. The cognitive-behavioural approach is among the most widely used intervention models in Europe in the treatment of IPV perpetrators (Arce et al. 2020) and SMP is a programme that incorporates not only cognitive-behavioural strategies but also MI, aiming to reduce ambivalence and promote motivation for behavioural change (Austin et al. 2011). For these reasons, it is believed that the present study brings important contributions to the intervention with IPV perpetrators within the Portuguese population.

From the analysis of the results of the ECVC and the Levenson Scale, no statistically significant differences were observed from pre- to post-test. However, the results obtained deserves some reflection. Regarding supportive IPV attitudes, the participants revealed a slight decrease in total scores and factor scores from pre- to post-test. Although the results did not reach statistical significance, as Echeburúa and Fernández-Montalvo (2009) stated, the decline in attitudes towards IPV in a brief intervention is particularly significant since such attitudes are a result of a long learning process. In addition, this slight change in the individuals’ beliefs system may promote the adoption of healthy behaviours and the rejection of abusive strategies in intimacy (Quintas et al. 2012). However, participants still scored considerably high on attitudes towards IPV, mainly regarding the legitimizing beliefs of violence by the conduct of women, which is partially corroborated by other studies. According to González-Ortega et al. (2008), the more conservative beliefs regarding the roles of men and women are related to the tendency of men to use violence and blame women for the violence suffered, with many of these beliefs associated with inequalities between the two sexes.

Regarding the Levenson Scale, the participants did not show pronounced traits of psychopathy, which is consistent with prior studies with Portuguese IPV perpetrators (Cunha et al. 2021, 2018). However, and despite not being significant, slight decreases were found in Factor 1, i.e., manipulation, envy, insensitivity, and indifference. Even if not significant, these reductions are particularly important as literature reports that these traits are related to IPV frequency and risk (Atkins et al. 2005; Conboy 2012; Cunha et al. 2018). This is even more important as the SMP intervention is brief, i.e., five sessions only, and a positive change in personality traits is worthwhile. Nonetheless, it is also important to note the slight increases in Factor 2, i.e., impulsivity and behavioural control, again not statistically significant, which has been related with general repeated offenses among IPV perpetrators (Cunha et al. 2021).

Concerning IPV recidivism risk, our results revealed that, overall, all the participants showed low recidivism risk, both at pre- and post-test assessments. Even so, participants revealed statistically significant reductions in recidivism risk from pre- to post-test, which is related to a lower probability to perpetrate IPV in future. This result is in accordance with previous literature that uses MI (Cunha et al. 2023a, b; Lila et al. 2018), reinforcing the importance of using MI to potentiate behavioural changes in this specific population. Nonetheless, it is important to mention that low-risk perpetrators tend to show greater treatment acceptance and commitment, when compared to high-risk perpetrators, resulting in greater motivation for change (McMurran 2009), which may explain the results. Indeed, our results revealed that all the participants were in an advanced stage of change at intake (in the preparation for action or even action phase), as they have shown themselves to be very involved and committed to their change. With participants in more advanced stages of change, the use of MI is to assist in creating a plan for the future and strengthen their motivation and self-confidence for the realization and maintenance of the necessary changes to be conducted (Devereux 2009).

The results concerning the clinical change in attitudes towards IPV and psychopathy after completion of the SMP are aligned with the results of the group tests. These are particularly interesting results because instead of focusing on the differences of mean scores, it provides information about treatment effects for each individual. This analysis offers a more accurate view of the results of each participant, allowing us to ascertain whether the observed change in the individual is in fact genuine and not just due to measurement errors (e.g., averages can mask the real change due to their dispersion) and whether the change places the individual inside the norms of functional groups (Conboy 2012). It is important to highlight that the results did not reach statistical significance, so there should be caution with its interpretation. However, the absence of significant changes is not surprising given the small number of sessions (i.e., five sessions) and the main goals of SMP. In fact, SMP was designed to enhance motivation and commitment for change and not to change supportive IPV attitudes or psychopathic traits. Keeping this in mind, any slight change, even if non-significant, is still valuable.

The results of the correlations conducted highlight the complex interaction between sociodemographic and juridical variables and attitudes supportive of IPV. One notable observation is the significant negative correlation between educational level and attitudes supportive of IPV, suggesting that higher levels of education are associated with lower levels of acceptance of such behaviours (e.g., Wang 2016). This correlation remained evident even after the intervention, though with a slight reduction in strength, suggesting that the influence of education on attitudes supportive of IPV persists. This may be corroborated by other studies (e.g., Oğuztüzün et al. 2023) which found that years of education had a direct effect on the effectiveness of IPV treatment in terms of overall violence, demonstrating the direct impact of education level on IPV perpetration. These findings highlight the need for comprehensive approaches that take into account both individual psychological factors and socio-demographic variables.

The correlations between stalking and IPV suggest that stalking behaviors are associated with lower levels of legitimisation of violence as a result of external factors (alcohol, unemployment, drugs, economic difficulties, extramarital affairs). Although literature shows that stalking behaviors and IPV perpetration and legitimisation often co-occur (e.g., Kim and Cho 2022), other studies have reported either no or diminished associations between past violence and stalking behaviors (e.g., Cunha et al. 2023a, b; McEwan et al. 2007), which aligns with our findings.

The interviews highlighted the great commitment on the part of the participants to make changes in their lives with a view to several objectives, focused on family (e.g., family proximity) and work (e.g., professional progression), which may indicate adequacy of the SMP in a correctional setting. This was also corroborated by the fact that participants demonstrated a reduction in ambivalence in the initial sessions, corroborating the study by Austin et al. (2011), which found that perpetrators who completed the SMP showed greater commitment to change and less ambivalence in the initial sessions.

The qualitative data obtained also allowed to perceive that participants with a history of alcohol consumption and substance abuse showed no interest in persisting in both consumption and abuse, stating that prison was positive in their lives because it allowed them to conduct treatment for these problems. Indeed, studies revealed that prisons are a unique context to provide health care and treatment conditions to individuals when those are needed, especially for those who are socially excluded (Echeburúa and Fernández-Montalvo 2009; Wise 2004). Although the participants describe the prison environment as depressing and suffocating, some recognize positive aspects of their sentence, faced as a moment of reflection, evolution, learning and, for some, a turning point. This is consistent with prior investigations on inmates’ perceptions about the rehabilitative potential of prisons (Andvig et al. 2020; Day 2020).

The participants also mentioned understanding the importance and impact that the changes made had (and will have) on themselves and their lives. Although all participants reported to be sorry for their aggressive conduct, some associated this regret with the fact that they were convicted, while others associated it with the impact that their behaviour had on the victims. This leads one to believe that, although there is such remorse and motivation for change, the reasons for this motivation might be related to the fact that at least some participants want to achieve social desirability and avoid recidivism. When someone feels guilty about a certain behaviour such as aggression, in this case, it is common to experience tension, remorse and repentance (Tangney et al. 2014). When regret exists, motivation directs to the repair of the damage caused and promotes improvement (Hooge et al. 2010).

The study by Austin et al. (2011) demonstrated a significant increase in the motivation for the change of perpetrators from the pre-test moment to the post-test, with stability in this change over three to 12 months after the application of the SMP. During the interviews, the participants of this study revealed to be motivated for change, which was expected and corroborates the results of Austin et al. (2011) study. However, some participants reported no longer to be changed, because staying in prison had already allowed them to make all the changes previously necessary. This brings us to the possibility that these participants are already in a more advanced stage of change (Devereux 2009) and consequently raises the hypothesis that these participants had already been the target of some kind of intervention prior to the application of the SMP.

The link between the categories identified in the thematic analysis and the findings concerning the risk of IPV is notable. Categories primarily centred on change and participants' motivation for change seem to exhibit a significant association with the observed low risk of IPV. It is conceivable that the intensity of motivation for change may have had a direct impact on the likelihood of perpetrating IPV, suggesting a possible correlation: as motivation for change increases, the risk of IPV decreases. This finding may be supported by other studies (e.g., Lila et al. 2018), which have found that, after an intervention including MI, IPV perpetrators have completed the intervention at a more advanced stage of change and have also reported a reduction in both physical and psychological violence. As individuals have demonstrated that they are actively seeking or implementing change within themselves and that they understand that their IPV behaviour is wrong, they will be less likely to perpetrate it. However, while the association between motivation for change and reduced risk of IPV appears promising, this interpretation must be treated with caution.

This study has several limitations. Considering the pandemic situation, the sample collection was initiated later than expected and, as a result, the number of participants was eventually lower than previously planned. Due to these circumstances, it was also not possible to set up a control group, which would have been of high importance for the research in question. This must be contemplated in future studies. The absence of a follow-up session is another important limitation, essential to monitor the maintenance and consolidation of the changes recorded. Then, due to the small size of the sample, it was not possible to obtain more diversified data. It is therefore important in future studies to diversify and extend the sample, aiming to obtain more significant and relevant results in this topical area.

This study proved to be relevant in introducing a new intervention programme in the Portuguese context. Although it requires further analysis and assessment, it is expected that, eventually, it will be possible to implement the SMP, as a complementary programme to the PIPs. Austin et al. (2011) suggested that prior to the implementation of a specific intervention programme, the application of the SMP should make the results of the following programme more effective, by promoting motivation. This data would only be verifiable by conducting a follow-up session after the participants adhere to an intervention programme addressing their problems. In this way, it would be possible to confirm whether the SMP actually motivated the participants to commit themselves to the next intervention, and whether it had an impact on recidivism and criminal risk. This should be considered at short-term, further deepening and developing the present research in future studies.

Conclusion

Readiness for change is identified as one of the indicators most consistently associated with overall success in perpetrators treatment and its absence associated with high dropout rates among PIPs. Since the SMP is not a specific programme for a particular problem, it may be applied to any offending person, regardless of conviction, gender, or age, and should be considered as a supplementary programme. The SMP allows the offending to reflect on the crime committed, on its objectives and plans for the future, allowing to understand the need to make changes. Accordingly, when this prior understanding exists, the offender will feel more prepared for the next intervention programme, looking at it with greater commitment.

The present study made it possible to understand the effectiveness of the SMP and the underlying MI, which may prove to be an advantage to PIPs. Although positive changes resulting from the application of the SMP and MI were found, there is still a long way to go and further research in this scope is essential, in order to further explore the programme, its effectiveness and its impact on perpetrators behaviour.