This is a page with a very good description of causes and symptoms of hoarding: About Hoarding
A simple guide to helping a hoarder yourself – Health Navigator New Zealand – How To Help A Hoarder
Support Groups and Professional Services
A choice of contacts and groups for mental health support – Mental Health Foundation – Support Groups
Psychology Today NZ – Hoarding Disorder to find therapists who can help with hoarding behaviours, enter your postcode in the box just below the blue banner at the top. Click GO. Click the Issues button. Click Show More Issues. Click Hoarding.
Auckland Libraries has several books on the subject of understanding and managing hoarding behaviours: Books about hoarding behaviours that you can borrow.
This page focuses on some of the findings from focus groups, literature and lived experiences about clinical approaches for hoarding: https://www.healthnavigator.org.nz/clinicians/h/hoarding-clinical-approaches/
The Taranaki DHB have written an interesting document a few years ago: Hoarding And Squalor Guidelines
The Southern DHB wrote something very similar: Good Living Conditions Southern
This UK public Facebook group shares useful information and articles for people with hoarding behaviours, professionals who help them and family and friends. https://www.facebook.com/HoardingDisordersUK/