Hoarding disorder is characterized by excessive amassment of objects in the home and difficulty of getting rid of the objects. It is associated with a high level of somatic and psychiatric comorbidity, suicidality, social marginalization, damage to property and risk of eviction. Previous clinical studies have mainly been in help-seeking groups. However, social services engage severe cases with poor insight, whereas few as 10% have contact with mental health services.

This study investigates:

1. The prevalence of severe mental illness and comorbidities among 60 individuals with hoarding disorder that have led to contact with social services at Copenhagen Municipality
2. the effect of a cross-sectoral intervention aiming to establish contact with regional mental health services for these individuals. The intervention consists of an outreach team of clinicians and municipal social workers who refer participants to clinical services based on a systematic clinical assessment.

Primary outcomes are 1) primary and comorbid diagnoses assigned at the clinical assessment and 2) contact with mental health services after the intervention, at 3- and 6-months follow-up.

Six to 12 months after the baseline assessment, a qualitative follow-up interview will be carried out, including approximately 14 participants. The aim is to explore the participants' experience of the intervention and subsequent clinical and social services to provide a more nuanced understanding of the quantitative outcomes of the study.

The hypotheses of the study are

1. more than 75% of the participants will be identified to have comorbid diagnoses including more than 50% with associated severe mental illness (schizophrenia, other psychotic disorders, bipolar disorder and periodic depression). It is expected that 10% will suffer from underlying organic disorders of dementia or mental retardation.
2. Fifty percent of the sample will establish contact with mental health services within 3 months after attempt of referral, and 30% of the sample will remain in contact for more than 6 months

The cross-sectoral intervention:

The intervention consists of an outreach (assertive and flexible) team of clinicians and municipal social workers targeting individuals with hoarding disorder who have ongoing contact with The Housing Advisors, Copenhagen Municipality. The clinical team includes the PhD student, the primary supervisor, and the co-supervisor, both clinical associate professors and senior consultants.

The Housing Advisors is a unit that provides support to citizens with housing-related difficulties. Their work focuses on preventing evictions and severe violations of fire and other safety regulations, and otherwise helping citizens to maintain their housing in cases involving hoarding, The Housing Advisors offers advice and guidance, support for solving hoarding related difficulties, and arranges municipality funded cleaning. Citizens acceptance or decline to participate in the research project will not affect the work carried out by The Housing Advisors or citizens' right to receive help from The Housing Advisors now or in the future.

Based on the clinical assessment, the team facilitates referrals of research participants to the appropriate regional mental health services, if referral is relevant. Referrals will take place after informed consent and are expected to primarily involve Flexible Assertive Community Treatment (FACT), which is standard of care in Capital Region Denmark for patients with persistent psychiatric disorders and low level of functioning. For other patients, referral to specialized clinics offering cognitive behavioral therapy will be relevant. Somatic complaints will be referred to the patient's GP or secondary somatic services. The team will communicate diagnosis and the plan for referral to the participant. Family members and significant others will be involved if desired by the participant.

The task of the social workers in the intervention will be the same as their current function in The Housing Advisors as outgoing case managers regarding the social issues of their clients. Moreover, the social workers will participate in the recruitment of the approximately 60 research participants.

As part of the research project, conferences between the research team and The Housing Advisors will be held, where information from the clinical assessment will be shared, including any relevant psychiatric history, current symptoms, diagnosis established in the research project and the plan for outpatient psychiatric treatment, with the aim of contributing with knowledge that could support the work of The Housing Advisors. The participants have the possibility to decline sharing clinical information with The Housing Advisors, by crossing yes or no in the consent form, without any consequences for their participation in the project.

The intervention is pragmatic and relatively low-cost. It is based on existing clinical and municipality structures but adds an integrated cross-sectoral and outgoing approach for initial clinical assessment. It is designed as a single-group, pretest-posttest trial, and will not include a control group. First, the investigators find it ethically correct to offer the intervention to all potential participants, sinceThe Housing Advisors estimate that only 10% of the target group currently receives treatment. Second, there is little empirical literature about non-help-seeking people with severe hoarding. By providing the intervention to the whole group, the project can gather comprehensive data which can inform future interventions and studies.

Baseline assessment:

The clinical interviews will be carried out by a PhD-student. Consultations will take place at municipality facilities, at research facilities or in the participants' home according to the preferences of the participant.

The interviews will be semi-structured and will include a psychosocial and illness history, the Present State Examination (PSE), which addresses general psychopathology and is a well-established instrument for a diagnostic assessment, the Positive and Negative Syndrome Scale (PANSS), which targets the severity of positive, negative, and general symptomatology, the Hoarding Rating Scale-Interview (HRS), the Global Assessment of Functioning Scale - Split version (GAF) and the Personal and social Performance scale (PSP). For assessment of schizotypal symptomatology, the assessment includes the Examination of Anomalous Self-Experience (EASE) and an extended checklist of symptoms and expressive features and behavior described in previous studies. Moreover, the PhD student will obtain the Saving Inventory-revised (SIR), which is a self-rating measure used in most clinical investigations of hoarding disorder, the Clutter Image Rating scale (CIR) which is a photographic self-rating scale, the Home Environment Assessment Tool for Hoarding (HEATH),which is a tool to assess the home for health and safety risks, and the Manchester Short Assessment of Quality of Life (MANSA). Brief assessment of impaired cognition (BASIC) will be used for screening for cognitive impairment as part of the clinical assessment of dementia. Finally, the investigators will assess intellectual functioning using three subtests from the Wechsler Adult Intelli-gence Scale, Fourth Edition (WAIS-IV): Similarities, Vocabulary, and Information. Scores from these subtests will be combined to derive the Verbal Comprehension Index (VCI), which provides an estimate of verbal intellectual functioning.

Furthermore, a qualitative phenomenological substudy will be conducted in a subgroup of particpants to elucidate the onset, progression, and thematic elements of the participants' hoarding behavior, as well as its overlap with different psychopathology.

Finally, the investigators will assess the somatic status of the patient, by making a systems enquiry and conducting a physical examination. No invasive procedures will be made.

Qualitative follow-up interview:

Approximately 6-12 months after the baseline assessment, a pre-graduate research assistant (PGRA) will carry out a qualitative interview (estimated 1.5-hour duration). The purpose of this interview is to qualitatively explore the participants' experience of the intervention and subsequent clinical and social services to provide a more nuanced understanding of the quantitative outcomes of the study. The aim is to include 14 participants in this follow-up interview (among participants that have been referred to clinical services) to represent the expected broad range of comorbidities and diversity in the sample and yet balancing this priority with the in-depth and time-consuming nature of a qualitative research project.

The interview will explore. 1) participants narration of the development of their hoarding behavior, quality of life, interpersonal relations and functioning over the last 6 months after the principal intervention; 2) their experience of the research intervention and subsequent process of transition to clinical services, including the coordination or lack of such between the clinical researchers, social workers and clinical services; 3) an overall narration of the participants experience of clinical services; treatment, clinical approach to hoarding and relations to clinicians and other partners such as municipality workers or other agents; 4) reasons for terminating or sustaining contact with clinical services. Moreover, the PGRA will re-administer the SIR, CIR, MANSA self-rating scales and the PSP and HEATH assessment.

Ethics Individuals with hoarding disorder is a marginalized group in society and this study aims to better the conditions for this group. Hoarding disorder is underexamined in the European as well as international literature and no studies of integrated approaches working across sectors have yet been carried out.

With this in consideration, and the fact that the only side expected side-effect is fatigue after the interviews, the investigators do find that the therapeutic and supporting benefits for the participants and future patients warrants the study and overweighs the effort the participants engage in the study. Hopefully, the study will contribute to a better understanding of hoarding disorder and improve treatment for this group, to the benefit of the participants, future patients, the scientific environment and society in general, as well as creating the foundation for future research about hoarding disorder and the implementing off a cross-sectorial approach for vulnerable, non-help seeking groups of patients.

Funding:

The study has been financed by The Independent Research Fund Denmark.

Inclusion Criteria:

• Presence of hoarding disorder according to DSM-5 and age above 18 years.
• Current contact with The Housing Advisors, Copenhagen Municipality.

Exclusion Criteria:

• Recent contact with mental health services (within last 6 months).
• Previously known organic brain disorder (including mental retardation and dementia).

If accepted the data will be deposited by the Danish National Archives.

Acces to the data is not decided by the researchers, but by the Danish National Archies.

If accepted by the Danish National Archives, the data will deposited after completion of the study.