Guidebook

Multisystemic Therapy for Problem Sexual Behaviour

Multisystemic Therapy for Problem Sexual Behaviour (MST-PSB) is an intensive intervention for families with a young person aged between 11 and 17.5 years old who has committed a sexual offence or demonstrated problematic sexual behaviour. It is delivered by MST-PSB therapists individually to the young person and family in their home, for an average of six to nine months.

The information above is as offered/supported by the intervention provider.

Population characteristics as evaluated

11 to 17 years old

Level of need: Targeted-indicated
Race and ethnicities: Black, Hispanic, White.

Model characteristics

Individual

Setting: Home, Out-patient
Workforce: Early years specialist
Full evidence description (PDF)
View programme website
Evidence rating:
Cost rating:

Child outcomes:

  • Enhancing school achievement & employment
    • Improved school grades
  • Preventing crime, violence and antisocial behaviour
    • Improved behaviour
    • Reduced antisocial behaviour
    • Reduced arrests
    • Reduced incarcerations
  • Preventing substance abuse
    • Reduced substance misuse
  • Supporting children’s mental health and wellbeing
    • Improved family relationships
    • Improved mental health
    • Improved social emotional skills

UK available

UK tested

Published: April 2025
Last reviewed: September 2017

Model description

Multisystemic Therapy for Problem Sexual Behaviour (MST-PSB) is an adaptation of the original Multisystemic Therapy model that was developed for children and young people aged 10 to 17.5 years old with sexually related delinquent behaviours, including aggressive (e.g. sexual assault, rape) and non-aggressive (e.g. molestation of younger children) sexual offences.

It is delivered by MST-PSB therapists individually to the young person and family in their home, or other setting that is convenient for the family, for an average of six to nine months. Services are intensive, with intervention sessions conducted from once a week to every day. A 24 hour/7 day per week on-call schedule is utilised to provide round-the-clock availability of clinical services for families. Each therapist carries a maximum caseload of four families and case length ranges from five to seven months.

The MST-PSB model assumes that the family is the primary agent of change, so most treatment sessions are delivered to the entire family. Extended family members may also be included in these sessions.

In the initial phases of the intervention, the therapist implements a highly individualised treatment plan with a strong focus on youth’s grooming behaviours (when present), family and youth characteristics related to sexual offence, community/physical environment and history of sexually abusive behaviours. The therapist then works with the family to identify the ‘fit factors’ that are driving the problematic child behaviours and the package of support the family subsequently receives is tailored specifically to address these factors.

Fit factors typically addressed by the model include:

  • Reducing caregiver and youth denial about the problem sexual behaviours and their impact on others
  • Implementing effective parenting practices (i.e. rules, privileges, and consequences) that are appropriate to the youth’s developmental stage
  • Supporting caregivers in the development and ongoing adaptation of plans for risk reduction, relapse prevention, and victim safety
  • Promoting cohesion and communication between family members.

The youth’s parents are also supported to conduct peer-level interventions which encourage positive relationship skills and friendships.

Age of child

10 to 17.5 years old

Target population

Families with a young person aged between 10 and 17.5 years old who has committed a sexual offence or demonstrated problematic sexual behaviour.

Disclaimer: The information in this section is as offered/supported by the intervention provider.

Why?

Science-based assumption

Between .5 and 1% of young people will have committed a sexual crime before adulthood.

Science-based assumption

Problematic sexual behaviour during adolescence is multi-determined by risks occurring at the level of the child, family, school, and community.

Who?

Science-based assumption

Parenting behaviours can stop or curtail problematic sexual behaviour when it occurs.

How?

Intervention

The family is supported to recognise factors contributing to problematic sexual behaviours and implement strategies to mitigate these factors.

What?

Short-term

Reduced family denial

Improved parenting practices

Improved family communication.

Medium-term

Reduced problematic sexual behaviour in the young person

Improved child behaviour.

Long-term

Reduced risk of sexual offences.

Who is eligible?

Families with a young person aged between 10 and 17.5 years old who has committed a sexual offence or demonstrated problematic sexual behaviour.

How is it delivered?

  • MST-PSB is delivered by a therapist who works individually with the young person and family in their home, for an average of 6 to 9 months.
  • Therapy sessions typically last between 50 minutes and 2 hours. The frequency of the sessions vary depending on the needs of the family and the stage of the treatment; however, sessions usually range from three days a week to daily.
  • Therapists work in the community in teams of 3 to 4 therapists plus a supervisor. The therapists are available to the family 24/7, and carry a caseload of 3 to 4 families at a time.

What happens during the intervention?

A variety of intervention strategies are used individually with the young person, their caregiver(s), and the wider family. Used strategies include: family discussions, role plays, structural family therapy, safety planning, and sexual education.

Who can deliver it?

The practitioner who delivers this intervention is an MST-PSB therapist, typically a psychologist or social worker with a master’s qualification or higher.

What are the training requirements?

  • Practitioners have 46 hours of intervention training in total.
  • Booster training of practitioners is recommended.

How are the practitioners supervised?

It is recommended that practitioners are supervised by:

  • One host-agency supervisor, typically a master’s qualified psychologist or social worker, with 82 total hours of intervention training.
  • One intervention developer supervisor, typically a master’s qualified psychologist or social worker.

What are the systems for maintaining fidelity?

Intervention fidelity is maintained through the following processes:

  • Training manual
  • Other printed material
  • Other online material
  • Video or DVD training
  • Face-to-face training
  • Fidelity monitoring.

Is there a licensing requirement?

Yes

Contact details*

Contact person: Richard Munschy

Email address: munschy@mstpsb.com

Website/s: http://www.mstpsb.com
http://mstservices.com/
http://mstuk.org

*Please note that this information may not be up to date. In this case, please visit the listed intervention website for up to date contact details.

Multisystemic Therapy for Problem Sexual Behaviour’s most rigorous evidence comes from two RCTs conducted in the United States consistent with Foundations’ Level 3 evidence threshold. As one of these evaluations includes evidence showing that child benefits persist past one year, MST-PST receives a rating of Level 4 rating overall.

These studies observed statistically significant reductions in sexual and non-sexual crimes, reduced problematic sexual interests, reduced psychiatric problems, reduced substance misuse, improved peer relationships, improved school performance, and a reduced likelihood of an out-of-home placement due to problematic sexual behaviour.

Child outcomes

Improved emotional bonding with peers

Immediately after the intervention

Improvement index

+42

Interpretation

4.24-point improvement on the Missouri Peer Relations Inventory (Parent report)

Study

1

Improved emotional bonding with peers

Immediately after the intervention

Improvement index

+39

Interpretation

1.78-point improvement on the Missouri Peer Relations Inventory (Child report)

Study

1

Improved social maturity with peers

Immediately after the intervention

Improvement index

+38

Interpretation

2.70-point improvement on the Missouri Peer Relations Inventory (Parent report)

Study

1

Improved social maturity with peers

Immediately after the intervention

Improvement index

+39

Interpretation

2.49-point improvement on the Missouri Peer Relations Inventory (Child report)

Study

1

Reduced psychiatric symptoms

Immediately after the intervention

Improvement index

+32

Interpretation

0.42-point improvement on the Global Severity Index of the Brief Symptom Inventory

Study

1

Reduced deviant sexual interests

Two years later

Improvement index

+20

Interpretation

0.86-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Youth report)

Study

2b

Reduced deviant sexual interests

Two years later

Improvement index

+16

Interpretation

0.68-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Parent report)

Study

2b

Reduced deviant sexual interests

One year later

Improvement index

+12

Interpretation

0.51-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Youth report)

Study

2a

Reduced deviant sexual interests

One year later

Improvement index

+15

Interpretation

0.65-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Parent report)

Study

2a

Reduced sexual risk/misuse

Two years later

Improvement index

+15

Interpretation

0.65-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Youth report)

Study

2b

Reduced sexual risk/misuse

One year later

Improvement index

+15

Interpretation

0.65-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Youth report)

Study

2a

Reduced sexual risk/misuse

One year later

Improvement index

+23

Interpretation

1.02-point improvement on the Adolescent Clinical Sexual Behaviour Inventory (Parent report)

Study

2a

Reduced out-of-home placements

One year later

Improvement index

+2

Interpretation

0.07-point improvement on the Services Utilization Tracking Form

Study

2a

Reduced out-of-home placements

Two years later

Improvement index

+19

Interpretation

0.85-point improvement on the Services Utilization Tracking Form

Study

2b

Improved school grades

Immediately after the intervention

Improvement index

+39

Interpretation

1.27-point improvement on parent and teacher-rated grade achievement

Study

1

Reduced externalising symptoms

One year later

Improvement index

+16

Interpretation

2.49-point improvement on the Youth Self Report

Study

2a

Reduced delinquent behaviour

Two years later

Improvement index

+20

Interpretation

0.90-point improvement on the Self-Report Delinquency Scale

Study

2b

Reduced delinquent behaviour

One year later

Improvement index

+21

Interpretation

0.92-point improvement on the Self-Report Delinquency Scale

Study

2a

Reduced aggression towards peers

Immediately after the intervention

Improvement index

+43

Interpretation

5.09-point improvement on the Missouri Peer Relations Inventory (Parent report)

Study

1

Reduced arrests for nonsexual crimes

8.9 years later

Improvement index

+21

Interpretation

3.42 reduction in arrests for nonsexual crimes

Study

1

Reduced number of person-related crimes

Immediately after the intervention

Improvement index

+34

Interpretation

6.60-point improvement on the Self-Report Delinquency Scale (Immediately after the intervention)

Study

1

Reduced number of property crimes

Immediately after the intervention

Improvement index

+31

Interpretation

27.95-point improvement on the Self-Report Delinquency Scale

Study

1

Reduced arrests for sexual crimes

8.9 years later

Improvement index

+31

Interpretation

0.66 reduction in arrests for sexual crimes

Study

1

Reduced days spent in detention facilities

8.9 years later

Improvement index

+24

Interpretation

80% reduction in days spent in detention facilities

Study

1

Reduced substance use

one year later

Improvement index

+27

Interpretation

1.2-point improvement on the Personal Experiences Inventory

Study

2a

Search and review

Identified in search10
Studies reviewed10
Meeting the L2 threshold0
Meeting the L3 threshold2
Contributing to the L4 threshold0
Ineligible8

Study 1

Study designRCT
CountryUnited States
Sample characteristics

48 families in which the youth (mean age = 14 years) has been arrested for a serious sexual offence.

Race, ethnicities, and nationalities
  • 72.9% White
  • 27.1% Black
  • 2.1% Hispanic.
Population risk factors
  • The youths had on average been arrested 4.33 times for sexual and nonsexual crimes
  • 54.8% of the families were of lower socioeconomic status.
Timing

Post-intervention and 8.9 year follow-up.

Child outcomes

Post-intervention

  • Reduced psychiatric symptoms (Youth report)
  • Reduced youth behavioural problems (Parent report)
  • Reduced aggression (Parent, Teacher and Youth report)
  • Improved peer emotional bonding (Parent, teacher and youth report)
  • Improved social maturity (Parent, Teacher and Youth report)
  • Reduced criminal activity (Youth report).

8.9 year follow-up

  • Reduced arrests – Sexual and other crimes (Administrative records)
  • Reduced incarceration (Administrative records).
Other outcomes
  • Reduced parent psychiatric symptoms (Parent and Youth report)
  • Improved family relations – Cohesion and Adaptability (Parent and Youth report).
Study rating3
Citations

Borduin, C. M., Heiblum, N. & Schaeffer, C. M. (2009) A randomized clinical trial of multisystemic therapy with juvenile sexual offenders: Effects on youth social ecology and criminal Activity. Journal of Consulting and Clinical Psychology. 77, 26–37.

Study 2

Study designRCT
CountryUnited States
Sample characteristics

127 families in which the youth (aged 11 to 18 years) has been charged with a sexual offence.

Race, ethnicities, and nationalities
  • 54% Black
  • 44% White
  • 31% Hispanic.
Population risk factors

35% of youth had nonsexual offences in addition to sexual offences, ranging from ordinance violations to serious person-related offences. In the three months prior to baseline, 11% of the youth had received mental health services, and 4% had received substance abuse services.

Family economic status varied, with 33% of families earning less than $10,000/year, 38% earning $10,000 to $30,000/year, and 28.5% earning $30,000 or more, indicating that the participating families were generally socioeconomically deprived.

Many caregivers (41%) had not completed high school, while 27% were high school graduates, and 32% had completed one or more years of college.

Timing

Study 2a: Baseline, 6 months post-baseline, 12 months post-baseline

Study 2b: 18 months and 24 months post-baseline

Child outcomes

12-month follow-up

  • Reduced inappropriate adolescent sexual behaviours – Deviant Sexual Interests (Youth and Parent report)
  • Reduced inappropriate adolescent sexual behaviours – Sexual Risk/ Misuse (Youth and Parent report)
  • Reduced delinquent behaviour (Youth report)
  • Reduced youth substance use (Youth report)
  • Reduced externalising behaviour (Youth report)
  • Reduced out of home placements (Parent report).

24-month follow-up

  • Reduced inappropriate adolescent sexual behaviours – Deviant Sexual Interests (Youth and Parent report)
  • Reduced inappropriate adolescent sexual behaviours – Sexual Risk/ Misuse (Youth Report)
  • Reduced delinquent behaviour (Youth report)
  • Reduced out of home placements (Parent report).
Other outcomes

None

Study rating3
Citations

Study 2a: Letourneau, E. J., Henggeler, S. W., Borduin, C. M., Schewe, P. A., McCart, M. R., Chapman, J. E. & Saldana, L. (2009) Multisystemic therapy for juvenile sexual offenders: 1-year results from a randomized effectiveness trial. Journal of Family Psychology. 23 (1), 89–102.

Study 2b: Letourneau, E. J., Henggeler, S. W., McCart, M. R., Borduin, C. M., Schewe, P. A. & Armstrong, K. S. (2013) Two-year follow-up of a randomized effectiveness trial evaluating MST for juveniles who sexually offend. Journal of Family Psychology. 27, 978–985.

The following studies were identified for this intervention but did not count towards the intervention’s overall evidence rating. An intervention receives the same rating as its most robust study or studies.

Borduin, C. M., Henggeler, S. W., Blaske, D. M. & Stein, R. J. (1990) Multisystemic treatment of adolescent sexual offenders. International Journal of Offender Therapy and Comparative Criminology. 35, 105–114.

Note on provider involvement: This provider has agreed to Foundations’ terms of reference (or the Early Intervention Foundation's terms of reference), and the assessment has been conducted and published with the full cooperation of the intervention provider.

Cost ratings:

Rated 1: Set up and delivery is low cost, equivalent to an estimated unit cost of less than £100.

Rated 2: Set up and delivery is medium-low cost, equivalent to an estimated unit cost of £100–£499.

Rated 3: Set up and delivery is medium cost, equivalent to an estimated unit cost of £500–£999.

Rated 4: Set up and delivery is medium-high cost, equivalent to an estimated unit cost of £1,000–£2,000.

Rating 5: Set up and delivery is high cost. Equivalent to an estimated unit cost of more than £2,000.

Set up and delivery cost is not applicable, not available, or has not been calculated.

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Child Outcomes:

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Supporting children’s mental health and wellbeing: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Preventing child maltreatment: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Enhancing school achievement & employment: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Preventing crime, violence and antisocial behaviour: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Preventing substance abuse: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Preventing risky sexual behaviour & teen pregnancy: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Preventing obesity and promoting healthy physical development: Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient.

Evidence ratings:

Rated 2: Has preliminary evidence of improving a child outcome from a quantitative impact study, but there is not yet evidence of causal impact.

Rated 2+: Meets the level 2 rating and the best available evidence is based on a study which is more rigorous than a level 2 standard but does not meet the level 3 standard.

Rated 3: Has evidence of a short-term positive impact from at least one rigorous study.

Rated 3+: Meets the level 3 rating and has evidence from other studies with a comparison group at level 2 or higher.

Rated 4: Has evidence of a long-term positive impact through at least two rigorous studies.

Rated 4+: Meets the level 4 rating and has at least a third study contributing to the Level 4 rating, with at least one of the studies conducted independently of the intervention provider.

Rating has a *: The evidence base includes mixed findings i.e., studies suggesting positive impact alongside studies, which on balance, indicate no effect or negative impact.

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