Mentalisation-based online intervention for psychologically distressed parents: protocol of a non-randomised feasibility trial of the Lighthouse Parenting Programme-Online (LPP-Online)

Abstract

Introduction

Online-based interventions provide a low-threshold way to reach and support families. The mentalisation-based Lighthouse Parenting Programme is an established intervention aimed at preventing psychopathological development in children. The objective of this study is to examine the feasibility of an online adaptation of the Lighthouse Parenting Programme (LPP-Online), evaluating (a) recruitment capability, compliance, acceptability and satisfaction with the intervention; (b) the psychometric properties of and the acceptability regarding the adjunct psychological evaluation; and (c) the employed materials and resources. The study will also obtain a preliminary evaluation of participants’ responses to the intervention.

Method and analysis

In this monocentric, one-arm, non-randomised feasibility trial, n=30 psychologically distressed parents with children aged 0 to 14 years will participate in the LPP-Online for a duration of 8 weeks. The intervention consists of online group sessions and individual sessions, 38 smartphone-based ecological momentary interventions (EMI), and psychoeducational materials (website, booklet). At baseline (T0) and the end of the intervention (T1), parents complete self-report questionnaires as well as 7-day ecological momentary assessments (EMA) via smartphone. During the intervention, additional EMA are completed before and after the daily EMI. An interview regarding parents’ subjective experience with the intervention will be conducted at T1. The feasibility of the intervention, the psychological evaluation and the resources will be examined using descriptive and qualitative analyses. The preliminary evaluation of the parents’ response to the intervention will be conducted by analysing pre–post changes in questionnaire measures and the 7-day EMA as well as data of additional EMA completed before and after the daily EMI.

Ethics and dissemination

Ethical approval of the study has been obtained from the local ethics board (Faculty of Behavioural and Cultural Studies, University of Heidelberg). Consent to participate will be obtained before starting the assessments. Results will be disseminated as publications in peer-reviewed scientific journals and at international conferences.

Registration details

German Clinical Trials Register (DRKS00027423), OSF (https://doi.org/10.17605/OSF.IO/942YW).

Strengths and limitations of this study.

• Relevance of the intervention: Exploring the feasibility of an online intervention is essential to enhance the accessibility of specialised treatments designed to improve parent-child relationships. Research on such interventions is scarce, highlighting the necessity for investigation.

• Data collection methods: The study employs both quantitative measures (self-report questionnaires and ecological momentary assessment) and qualitative measures, administered pre-intervention and postintervention, to address research questions regarding the feasibility and preliminarily evaluate participants’ response to the intervention.

• Multicomponent intervention: The intervention integrates online-based synchronous group and single sessions with additional daily micro-interventions to improve transfer to daily parent–child interactions.

• Limited significance for efficacy: This study is primarily focused on assessing the feasibility of Lighthouse Parenting Programme-Online. While it aims to explore this aspect comprehensively, it is important to note that this study cannot adequately address the question of efficacy.

• Validity: Ecological momentary assessment of parental mentalising must be interpreted with caution as this measurement approach needs further validation.

Introduction

The COVID-19 pandemic has increased the risk of mental health problems and led to more hardship and heightened levels of caregiving stress in many families.^{1 2} Increased mental health problems and caregiving burden during the pandemic in many cases have a negative impact on the parent–child relationship.^{3 4} These calamitous outcomes are likely a consequence of social distancing, illness or death of close relatives as well as loss of work–family balance, financial strain or sudden unemployment. Domestic violence and adverse childhood experiences increased during the pandemic,⁵ particularly in families characterised by higher parental stress, feelings of loneliness, job loss, and younger parent and child age.^6–8 Although families were not equally negatively affected,⁹ the pandemic had a serious impact on parents and children, especially from vulnerable families, and increased the need for more flexible interventions that are compatible with everyday family life.

A growing body of research suggests that psychosocial risk factors hinder mentalising in the parent–child relationship.^10–12 Parental mentalising refers to the parent’s capacity to reflect on their own and their child’s internal experience (eg, intentions, feelings, wishes, cognitions, etc).¹³ Parents who experience more parenting stress have been found to show difficulties in mind-mindedness, a construct related to parental mentalising.¹⁴ Likewise, parental mental health difficulties may impair mentalising, for example, increased parental depression has shown a negative relation to parental mentalising (for a meta-analysis, see15). Risk factors for insensitive parenting behaviour, such as a history of neglect or abuse,¹⁶ are also associated with mentalising difficulties.¹¹ These risk factors can repeatedly trigger intense affective states in parents during interactions with their child, which may hinder parental mentalising. Importantly, higher parental mentalising has been found to be a predictor for secure parent–child relationships over and above sensitive parenting behaviour.¹⁷

There is a considerable evidence base for mentalisation-based treatments (MBT) working with adults,¹⁸ and in the past 15 years, research evaluating MBT for parents and families has also increased (eg, ^{19 20}). MBT programmes for parents have been developed especially for populations with high psychosocial risk factors, such as low socioeconomic status, disruptions in early attachment relationships, high parenting stress and trauma (eg,^{21 22}). By improving parents’ ability to reflect on their child’s mental states, even in challenging situations, maladaptive parenting behaviour may decrease and sensitive parenting behaviour may increase.²³ This, in turn, lays the groundwork for high-quality parent–child relationships and improved child mental health (eg,^{17 24}). In summary, improving parental mentalizing is a promising target to enhance parents’ ability to engage in sensitive interactions with their child, thereby mitigating negative effects of psychosocial parental risk factors on child mental health development.

Overall, research on the efficacy of MBT parenting programmes revealed promising results in terms of an increase in mother–child interaction quality (eg,²⁵) and a reduction in parental hostility and helplessness (eg,^{26 27}) as well as child psychopathology (eg,^{28 29}). A systematic review³⁰ synthesising the research on dyadic (ie, parent–child) MBT approaches for parents of babies and toddlers found that such interventions led to significant improvements in measures of parental mentalising, maternal depression and infant attachment. Lavender and colleagues³¹ recently summarised the results of studies on MBT parenting programmes in group settings in a systematic review. Out of the 10 included intervention studies, eight demonstrated an increase in parental mentalising. However, the quality of most included studies was rated as low to moderate. Thus, future research in this area is needed to confirm the findings. Additionally, most interventions targeted parents in difficult social circumstances or from psychosocial risk populations but, with few exceptions, not parents with mental health difficulties.

One of the programmes, the MBT Lighthouse Parenting Programme (LPP),³² aims to reduce parental stress and strengthen the parent–child relationship in high-risk parents by enhancing parents’ capacity to mentalise their child. Pilot evaluations of the face-to-face LPP found that it may be effective in improving parenting confidence and sensitivity and decreasing parenting stress.^{32 33} Currently, two randomised controlled trials (RCTs) are underway, evaluating the efficacy of the LPP for parents with children at risk for child maltreatment (OSF trial registration, https://osf.io/r8sxz) and for parents in psychiatric treatment.³⁴

During the pandemic, the number of parents in need of mental health interventions has increased, while barriers to accessing mental health services have risen for adults as well as children and adolescents (eg,^{35 36}). Although the efficacy of online-based interventions has been subject to research for several years,³⁷ the investigation of the feasibility and efficacy of online parenting interventions began later.³⁸ Research on the efficacy of internet-supported parenting interventions demonstrates promising effects, such as, for example, for parents of children with emotional and behavioural problems.^{39 40} The advantages of internet-supported interventions include reaching geographically isolated parents and those in need of specialised treatments,⁴¹ offering flexible access to trained providers, and reduced intervention delivery costs.^{41 42} Considering the increased burden on families and barriers to accessing care, there is an urgent need to establish easy-to-access interventions aimed at helping families to adapt to and reduce parental stress and strengthen the parent–child relationship.

This study will address the current lack of research by implementing an online format of the previously established parent intervention LPP-Online (LPP-Online) targeting psychologically distressed parents. An online adaptation of the LPP is a promising approach to enhance the accessibility of the intervention and specifically target everyday parent–child interaction problems. Therefore, this study aims to examine the feasibility of the LPP-Online as a prerequisite to conducting a pilot RCT. Specifically, this study will examine the programme regarding (a) recruitment capability, compliance, acceptability and satisfaction with the intervention; (b) the psychometric properties of the psychological evaluation and their acceptability in the population; (c) and the employed resources and therapeutic abilities. Furthermore, the study will obtain a preliminary evaluation of participants’ response to the intervention regarding measures of, for example, parenting stress, parental mentalising, and child emotional and behavioural problems.

Regarding the preliminary evaluation of participants’ response to the intervention, the study will employ an ecological approach and examine psychological constructs in everyday life before, during and after the intervention period. Ecological momentary assessments (EMA) offer the possibility of a high-frequency and real-time assessment of psychological constructs under naturalistic conditions.⁴³ The advantages of EMA are (a) an increase in ecological validity by monitoring psychological constructs in everyday life⁴⁴; (b) the reduction of retrospective bias by capturing momentary states when they actually occur;⁴⁵ and (c) the (micro-)longitudinal design, that is, the collection of several within-person measurements, which might guarantee more accurate assessments compared with a single measurement.⁴⁵

Primary research questions

To estimate the feasibility of a prospective pilot RCT, the primary research questions target the recruitment capability, acceptability and satisfaction with the intervention, the acceptability of the psychological evaluation (ie, questionnaires and EMA), and the resources and therapeutic abilities. Specifically, the following research questions will be examined.

Recruitment capability, acceptability and satisfaction with the intervention

• What are the recruitment rates?

• What are the characteristics of the study participants?

• What are retention, drop-out and compliance rates? What are the reasons for drop out?

• How satisfied are participants with the intervention?

Acceptability and psychometric properties of the psychological evaluation

• What are the retention and completion rates of self-report questionnaires and EMA?

• Are the questionnaires used to assess parents’ treatment response reliable? Are the items included in the EMA valid and reliable?

Resources and abilities

• What are the resources and therapeutic abilities needed to implement and manage the intervention and the psychological evaluation?

Secondary research questions

The secondary research questions aim at a preliminary evaluation of the participants’ response to the intervention. Specifically, the following research questions will be examined.

• Will participants show a pre–post change in subjectively perceived stress, parenting stress and psychological symptom severity as a result of the intervention and a pre–post change in subjectively perceived stress as a result of daily ecological momentary interventions (EMI)?

• Will participants show pre–post changes in parental mentalising abilities, emotion regulation abilities, epistemic trust, family function, parenting behaviour and relationship quality with the child following the intervention?

• Will participants report pre–post changes of child temperament (ie, negative affectivity/emotionality) as well as child emotional and behavioural difficulties as a result of the intervention?

• How will parents subjectively experience their participation in the LPP-Online?

Method

Trial design and setting

The study is a monocentric, one-arm, non-randomised feasibility trial on the LPP-Online conceptualised according to the CONSORT 2010 statement’s extension to randomised pilot and feasibility trials.⁴⁶ The purpose is to answer the overarching question of whether the intervention study can work.^{47 48} Therefore, five main objectives of the study were identified, focusing on recruitment, data collection procedures, acceptability of the intervention, resources to implement the study and a preliminary evaluation of participants’ responses to the intervention.⁴⁸

The study will be conducted at a single treatment centre in Heidelberg, Germany. Participating parents will participate in the LPP-Online intervention for 8 weeks. Parents will be asked to complete self-report questionnaires as well as a 7-day EMA before (T0) and after the intervention (T1) and to participate in EMA before and after the daily interventions (EMI). EMA and EMI will be conducted via a smartphone app. The study flow is depicted in figure 1.

Figure 1.

Study flow chart.

Consistent with,⁴⁷ the design of this feasibility trial is adaptive in terms of the recruitment procedure, intervention and psychological assessments in order to account for potential problems (eg, recruitment problems, high drop-out rates) hindering a successful termination of the study and to achieve the most promising format. This means that there will be an ongoing evaluation of the feasibility criteria during the study. If it becomes apparent that certain recruitment, intervention or assessment procedures are not successful, these will be adapted as the study is ongoing. All adjustments will be described in a subsequent publication on the feasibility trial.

Recruitment

Specialised family institutions and hospitals in Germany will be contacted via email, post and phone. Potential participating parents will be referred to the study centre at the Institute for Psychosocial Prevention, University Hospital Heidelberg. Recruitment has started in September 2021; the first patient was enrolled on 8 December 2021.

Inclusion and exclusion criteria

We include parents of all genders who are at least 18 years old and have at least one child aged up to 15 years. Specifically, we require that parents experience psychological stress in everyday life (eg, mental illness, psychosocial stress) and that the children are predominantly present at home or in parents’ everyday life. Further inclusion criteria are an ICD-10 F diagnosis (diagnosis of a mental, behavioural and neurodevelopmental disorder) or factors justifying an ICD-10 Z code (factors influencing health status and contact with health services), sufficient knowledge of written and spoken German, ability to give informed consent, and access to an internet-enabled PC, tablet or smartphone with camera and microphone and a valid email address. Parents with acute psychotic symptoms or acute substance abuse are excluded from the study.

Sample size

A sample size of n=30 psychologically distressed parents was defined based on practical aspects (eg, availability of therapists, equipment and funding). Considering the drop-out rates in previous MBT group-based parenting interventions (average rate of 17%,³¹), at least five intervention groups, each consisting of 6 to 8 parents, are required to reach a minimum total of n=30 participants. We expect that this sample size will allow us to capture a sufficient variety of experiences of parents regarding the intervention, based on which we can adjust the intervention and the accompanying study for a future pilot RCT.

Intervention

The LPP is a mentalisation-based and attachment-oriented group therapy programme designed for parents at risk for maltreatment.³² The programme consists of psychoeducational elements, reflection on different perspectives on child behaviour, and practical elements using role-playing and homework. Parents are taught easy-to-learn metaphors about attachment and mentalising, for example, that parents are ‘lighthouses’ who use their beam to illuminate (mentalise) their children and guide them to a ‘safe harbour’ (secure attachment), sometimes through a ‘rough sea’ (eg, pandemic or other stressful life situations). A focus of the group discussion and reflection lies on situations where the parent’s ‘illuminating beam’ (ie, mentalising skill) has gone out and the risk of conflict or abuse is high. In doing so, the therapist consistently supports the parent by focusing on their existing skills and resources.

The online adaptation is based on the German translation and adaptation of the programme for parents with mental illness.⁴⁹ It consists of the following programme elements: eight weekly group sessions and three individual sessions via virtual video conferencing software, adjunctive daily micro-interventions (EMI), and a digital booklet and additional psychoeducational resources (text, pictures and videos) on the website. Figure 2 depicts the elements and the process of the LPP-Online intervention.

Figure 2.

Intervention elements and process.

One-to-one individual sessions with each parent will be conducted at the beginning of the programme to assess psychosocial variables, relevant biographic information, mentalising capacities and individual therapy goals (each session lasting 50 or 90 min). Two additional individual sessions will take place during the 8-week programme and encompass a video-feedback session on parent–child interaction and the discussion of an individualised written feedback focusing on parental mentalising (a personalised letter written by the therapist to the parent). Additional individual sessions can take place as needed. The main part of the intervention consists of eight weekly group therapy sessions (with a duration of 120 min each). Between the group sessions, additional micro-interventions via smartphone (EMI) will be provided to practice and enhance the group session content (once a day with a duration of 5 to 15 min). In addition, psychoeducational material will be freely accessible via a digital booklet and a website and can be used by participants on their own initiative.

Measures

Primary outcomes

Recruitment capability, acceptability and satisfaction with the intervention

• recruitment, retention and completion rates: ratio of number of parents screened vs included, ratio of number of parents included vs number of parents who completed the intervention, drop-out rates, and reasons for drop out.

• compliance: treatment duration in weeks, number of attended sessions (group sessions, individual sessions), parents’ self-report on items regarding self-initiated use of the website, frequency of EMI use.

• characteristics of the study participants

• acceptability: parents’ self-report on items regarding the general technical design implemented via the smartphone app (overall impression, usability, graphics, technical deficiencies, suggestions for improvement), items regarding EMI (amount of time spent with EMI, perceived usefulness, appropriateness, comprehensibility and suggestions for improvement) and items regarding the use of the website (amount of time spent on the website, perceived usefulness, appropriateness, comprehensibility).

• satisfaction with the intervention: ZUF-8 questionnaire to evaluate parents’ satisfaction (adapted from⁵⁰), parents’ self-report on items regarding group sessions (usefulness, comprehensibility, amount of time spent in group sessions, appropriateness, suggestions for optimisation), Helpful Aspects of Therapy form (H.A.T., V.3.2).

Acceptability and psychometric properties of the psychological evaluation

• retention rates: percentage of parents completing pre-treatment and post-treatment self-report questionnaires and EMA.

• compliance: percentage of parents who completed the questionnaires, percentage of completed EMA, frequency the app was independently accessed, missing data.

• acceptability: acceptability of the self-report questionnaire assessments and EMA.

• validity: validity of the EMA items used to assess secondary outcomes.

• reliability: reliability of the questionnaires and EMA items used to assess secondary outcomes.

Resources and abilities to implement and manage the intervention and psychological evaluation

• scientific staff

• recruitment networks, clinical collaborations

• MBT training and supervision

• adherence to the LPP manual

• technical resources, including hardware (PC, laptop, tablet, smartphone), software (EMA and EMI) as well as videoconferencing providers.

Secondary outcomes

A list of secondary outcome measures on the participants’ responses to the intervention can be found in tables 1 and 2. The references for the outcome measures can be found in online supplemental appendix A.

Table 1.

Overview of the psychological assessment and the time points for the secondary outcomes

Construct	Measure	# items	Administered at T0	Administered at T1
Parental stress and stress experience	Eltern-Belastungs-Inventar (EBI1 German version of the Parenting Stress Index (PSI))	48	x	x
	Perceived Stress Scale (PSS-102, German translation3)	10	x	x
Psychological symptom severity	Patient Health Questionnaire (PHQ4)	16	x	x
Parental mentalising ability	Parental Reflective Functioning Questionnaire (PRFQ5)	18	x	x
	Parental Reflective Functioning Questionnaire-Adolescent (PRQ-A5)	18	x	x
Emotion regulation	Difficulties in Emotion Regulation Scale-Short Form (DERS-SF English version6; German translation of the long version7)	18	x	x
Epistemic trust	Epistemic Trust Questionnaire (ETMCQ8)	15	x	x
Family functioning	Systemic Clinical Outcome and Routine Evaluation-15 (SCORE-15, ie, English short version of SCORE-409, German translation10)	15	x	x
Parenting behaviour	Alabama Parenting Questionnaire (APQ11, German translation12)	38 (42)	x	x
Relationship quality with the child	Multiperspektivischer Fragebogen zur Eltern-Kind-Beziehung (MEK13, English translation: The Multiperspective Parent–Child Relationship Questionnaire)	18	x	x
Child temperament	Infant Behaviour Questionnaire (IBQ16, German translation17) (3 to 12 months)	37	x	x
	Emotionality, Activity and Sociability Temperament Inventory (EAS14, German translation by15) (1 to 14 years)	20	x	x
Child behaviour difficulties	Strengths and Difficulties Questionnaire (SDQ P 2–1718, German translation19) (2 to 17 years)	30	x	x
Subjective therapy experience	Semi-structured interview adapted from20	17		x

Table 2.

Overview of the psychological assessment and the time points in the ecological momentary assessment

Construct	Reference	# items	Pre-intervention/postintervention assessment (8 weeks)		During intervention: assessment before and after daily EMI
			T0	T1	Pre	Post
Valence	Short-scale tree basic dimensions of mood21	2	x	x	x	x
Arousal	Short-scale tree basic dimensions of mood21	1	x	x	x	x
Stress	Perceived Stress Scale (PSS-10, German translation)22 23	1	x	x	x	x
Social context	START Childcare24	2	x	x	x	x
Appraisal of the situation	Appraisal items25	5	x	x	x	x
Mentalising capacities	Mentalisation questionnaire26	3	x	x	x	x

EMI, ecological momentary interventions.

Assessment of treatment model fidelity

To evaluate the extent to which therapists adhere to the manual in delivering the LPP, all group sessions will be video-recorded as part of the routine supervision process. In total, 20% of the video-recorded therapy sessions will be selected and rated by members of the LPP scientific evaluation team and an external rater. The LPP Intervention Scale⁵¹ will be used to rate the degree of adherence. In addition, supervision groups and team meetings will be conducted to evaluate the model fidelity and decide on necessary adaptations of the manual.

All validated measures will be scored as recommended.

Data collection procedure

Once parents have given their informed consent, they will be sent an email with a link to the online assessment. Questionnaire data will be collected pre-treatment and post-treatment (T0, T1) via the online assessment tool SoSci Survey (figure 1), which takes about 30 min. Moreover, at T0 and T1, parents will participate in a smartphone-based EMA for 7 days. An interval contingent design will be implemented with randomly assigned assessments throughout participants’ waking hours, with an interval of at least 1.5 hours between the assessments. Additionally, parents will be invited to complete event-based assessments after an emotionally intense moment (eg, stressful situation with the child). During the intervention, EMA will be completed before and after the daily EMI, respectively. EMA and EMI will be implemented using the software Movisens.⁵² One-to-one interviews about parents’ subjective experiences will be conducted after T1.

Statistical analysis

Intent-to-treat principles will be used, and all parents assessed at T0 will be included in data analysis. Sociodemographic variables and data from the psychological assessments at baseline will be used to characterise the sample. Descriptive analyses will be conducted to answer the primary research questions. Additionally, descriptive data will be collected on drop-out reasons and content analysis will be used to examine qualitative data regarding the primary research questions (eg, drop-out reasons, open-ended questions obtained in online assessment).

To assess participants’ perceived satisfaction with the intervention, we will rely on participants’ self-report using the ZUF-8 questionnaire. The suitability and acceptability of the study procedures and the intervention will be descriptively determined, using data on retention, adherence to study procedures, intervention attendance and engagement with the intervention. Information about duration and comprehensibility of the procedures and intervention will be analysed both quantitatively and qualitatively. Furthermore, data on the burden, acceptability and satisfaction of the intervention will be analysed. Data from the H.A.T questionnaire will be considered in a subsample of the participants.

EMA and EMI data will be evaluated regarding retention and completion rates. To assess the validity of the EMA items, we will consider ratings on linguistic comprehensibility and clarity of item formulation. Also, the dynamic changes in momentary stress and mentalising ability over the day will be analysed.

The organisational and technical resources as well as the therapeutic abilities required to conduct the study will be descriptively and qualitatively analysed, focusing on administrative capacity, expertise, skills/fidelity, time, and financial and technical resources.

To answer the secondary research questions on the participants’ responses to the intervention, we will conduct explorative pre–post comparisons using one-sample t-tests or equivalent non-parametric tests and report effect sizes (Cohen’s d) and confidence intervals. We will rely on multilevel modelling for analysing changes in parameters of the 7-day pre-treatment and post-treatment EMA. To assess the differential effects of the EMI, pre-treatment and post-treatment EMA of subjectively perceived stress will be used to determine if there is a significant difference between the means of pre-treatment and post-treatment EMA.

The Grounded Theory method⁵³ will be employed to investigate participants’ subjective therapy experience based on the qualitative interviews, adhering to common guidelines.⁵⁴

As this is a preliminary analysis of the participants’ responses to the intervention, we will not correct for multiple hypothesis testing. Analyses of quantitative data will be conducted using the statistical software SPSS⁵⁵ and R.⁵⁶ Analysis of qualitative data will be supported by ATLAS.ti.

Progression criteria

The decision to proceed to a pilot RCT will be informed by an assessment of the feasibility outcomes according to a set of progression criteria determined a priori by the project team. These criteria were developed using the traffic light system, as proposed by.⁵⁷ These will likely be:

• recruitment rates (ratio screening/inclusion): >80% (green), 60%–80% (amber), <60% (red).

• retention/drop-out rates intervention: >70% (green), 50%–70% (amber), <50% (red).

• retention rates questionnaire assessments: >80% (green), 60%–80% (amber), <60% (red).

• retention rates EMA: >70% (green), 50%–70% (amber), <50% (red).

Patient and public involvement

Neither patients nor the public are directly involved in the design, choice of outcome measures or recruitment for the study.

Discussion

This protocol outlined the need, aim and methodology of a feasibility study on the newly adapted mentalisation-based LPP-Online intervention for psychologically distressed parents. The online format aims at overcoming challenges typically limiting the reach of interventions regarding burdened families.⁴² With a focus on parental mentalising, the programme targets a psychological capacity that has been identified as a cornerstone of good parent–child relations (eg,¹⁷). General evidence from mentalisation-based programmes for at-risk families^{30 31} and particularly preliminary evidence on the LPP in face-to-face settings^{32 33} further support the notion that an online adaption of this intervention may significantly contribute to a better family situation. Additional treatment components implemented in the LPP-Online, like psychoeducational material and micro-interventions provided on a daily basis, potentially contribute to better transfer effects on day-to-day interactions with the child and, thus, could strengthen the proposed intervention effects.

Based on the results of this feasibility study, in a second step, a pilot RCT will be conducted to investigate the preliminary efficacy of LPP-Online. Parents’ verbal evaluations at the end of treatment and their experience of the intervention will be considered when adapting the LPP-Online manual. For example, intervention components like certain EMI that may not be experienced as helpful by parents will be dropped in the adaptation of the manual. Likewise, quantitative data on feasibility indicators will be considered when planning a subsequent pilot RCT, for example, the intervention compliance rates or the retention rates of the questionnaire assessments. Furthermore, the resources needed to deliver the LPP-Online and to conduct the study can be used to plan a future pilot RCT. Finally, based on the results, measures can be selected that best capture the pre–post changes of the entire intervention and the EMI.

In addition to these strengths, several limitations need to be considered. Since this feasibility study does not employ a control group, it is not possible to assess the feasibility or acceptance of randomisation. Therefore, recruitment and drop-out rates obtained cannot be directly transferred to a subsequent pilot RCT. Similarly, pre–post effect sizes on the continuous outcome measures (ie, our secondary research questions) cannot be used to plan the sample size in a pilot RCT. Another limitation of our design pertains to the determination of sample size. The decision to aim for n=30 participants distributed over at least five groups was primarily based on practical considerations. While this sample and group size typically allows for a certain diversity of experiences, the relatively small size may result in less precise parameter estimations. Therefore, the findings only offer preliminary insights regarding the optimal design of a follow-up pilot RCT study. Further limitations concern the assessment instruments. In the domain of child outcome variables, we do not capture emotional and behavioural problems in children under the age of 12 months since the Strengths and Difficulties Questionnaire does not cover this age range. Another limitation is the reliance on self-report measures. Furthermore, it is important to note that the interpretation of the EMA data on daily parental mentalising should consider that the validation of this assessment approach is part of the study.

Our programme does not directly address mental health problems of parents. Rather, its primary goal is to positively influence parenting behaviour and the parent-child relationship (and ultimately the child’s mental health). The programme may be offered alongside individual psychotherapy for parents. Likewise, for participation in this study, simultaneous individual treatment is not an exclusion criterion. Accordingly, this feasibility study cannot provide information on how the programme could be implemented as a sole primary treatment for a mental illness in parents. Instead, the LPP-Online aims to assist psychologically burdened parents in regaining a more fulfilling experience of parenthood.

Ultimately, we aim to provide a treatment that reaches and engages parents who experience psychological distress and frequent conflicts with their child. LPP-Online may have the potential to increase parents’ mentalising abilities, improve parent–child relations, reduce parental stress and, thus, make families more resilient in the face of adversity and subsequently interrupt the intergenerational transmission of psychopathology. For this reason, future intervention studies should also investigate the potential long-term effects of the intervention on the mental health of children.

Ethics and dissemination

Ethical approval has been obtained from the local ethics board (Faculty of Behavioral and Cultural Studies, University of Heidelberg, AZ Volk 2021 1/2). Consent to participate in the study will be obtained from all parents before starting the assessments. Results from the study will be disseminated as publications in peer-reviewed scientific journals and at international conferences.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).