About

Dr Leander Dellers is a clinical psychologist, based in Sydney, with a PhD in Clinical Psychology from Griffith University. Originally from Switzerland, he moved to Australia to pursue his career in psychology. Leander speaks fluent Swiss-German, German, and English, and brings both cultural and professional diversity to his work. He has gained clinical experience across public health, community, and private practice settings, with clients of all ages, though he now focuses predominantly on working with adults (18+).

Leander is passionate about creating a warm, empathetic, and non-judgmental space for his clients. He strives to provide a safe environment where people feel comfortable exploring their thoughts, feelings, and life experiences. Central to his approach is building trusting relationships, fostering self-compassion, and supporting clients in developing practical tools to create meaningful and lasting change.

Leander has a strong interest in supporting and providing evidence-based support for clients living with Obsessive-Compulsive Disorder (OCD). He has completed advanced-level training in OCD treatment, developed during his time at Melbourne Wellbeing Group under the supervision of Dr Celin Gelgec. He is also passionate about working with a wide range of other mental health concerns, including anxiety, disordered eating and body image issues, relationship and social difficulties, emotional regulation, clinical perfectionism, self-esteem challenges, and stress management.

Leander is also deeply committed to supporting LGBTIQ+ clients. He offers an affirming space for people navigating questions of sexual or gender identity, including coming out, self-acceptance, or experiences of gender dysphoria. His academic research reflects this commitment, with his PhD having focused on sexual minority mental health and the impact of intragroup marginalisation within the male gay community.

Leander works flexibly and draws on a range of evidence-based therapies. These include Cognitive Behavioural Therapy (CBT), Acceptance and Commitment Therapy (ACT), Exposure and Response Prevention (ERP), Schema Therapy, Emotion-Focused Therapy, Mindfulness, Dialectical Behaviour Therapy (DBT), and Solution-Focused Therapy. He tailors therapy to each client’s unique needs and goals, ensuring that support is both collaborative and practical.

Black and white portrait of a smiling young man with short, styled hair, wearing a dark button-up shirt, against a plain light background.

    • Bachelor of Psychological Science (Honours, First Class), Griffith University

    • Doctor of Philosophy (PhD) in Clinical Psychology, Griffith University

    • AHPRA-registered Clinical Psychologist (PSY0002429877)

  • Director and Clinical Psychologist
    Dellers Psychology | Sydney, NSW
    Oct 2025 – Present

    Founder and director of Dellers Psychology. Providing compassionate, evidence-based therapy for individuals experiencing OCD, anxiety disorders, and disordered eating, as well as LGBTQ+-affirming care in Sydney and across Australia.

    Clinical Psychologist
    Melbourne Wellbeing Group | Surrey Hills, VIC
    Nov 2023 – Oct 2025

    Worked as a registered psychologist and clinical psychologist supporting clients managing OCD and related anxiety conditions. Completed advanced training in OCD treatment under Dr Celin Gelgec, integrating CBT, ACT, and exposure-based interventions.

    Registered Psychologist (Clinical Registrar)
    DS Psychology Group | Ringwood VIC
    May 2023 – Nov 2023
    Provided assessment and therapy for adults and adolescents presenting with anxiety and mood disorders, OCD, eating disorders, and other concerns. Focused on developing clinical skills in exposure-based and cognitive-behavioral approaches.

    Provisional Psychologist
    DS Psychology Group | Ringwood, VIC
    Jan 2023 – May 2023

    Delivered therapy under supervision for clients with a range of emotional and behavioural concerns, including anxiety, depression, and obsessive-compulsive symptoms.

    Provisional Psychologist (Clinical Placement)
    Gold Coast University Hospital | Southport, QLD
    Jan 2022 – Jun 2022

    Completed a clinical placement in the Acute Medical Psychology and Cancer Outpatient Services. Provided psychological support for individuals adjusting to medical illness using CBT, Solution-Focused Approaches, and Dignity Therapy approaches.

    Provisional Psychologist
    Griffith University Health Clinic | Southport, QLD
    Jan 2021 - Dec 2021

    Internship at the Griffith University Health Clinic as part of the Master in Clinical Psychology Program. Trained primarily in CBT approaches, provided supervised psychotherapy, diagnostic and cognitive assessments, as well as group-based therapy programs for children and parents.

    Psycho-Diagnostic Assistant
    University Psychiatric Clinic Basel | Basel, Switzerland
    Oct 2013 – Apr 2014

    Assisted with cognitive and psychometric assessments (intelligence, memory, and attention). Supported diagnostic evaluations and contributed to clinical reporting under supervision.

  • Research focus:

    • Sexual minority mental health

    • Intragroup marginalisation in LGBTQ+ communities

    • Stress, stigma, and resilience in sexual minority men

    • Broader mental health and social wellbeing outcomes

    Dissertations:

    • PhD Thesis (2025):
      “Excluded From Within: Examining Intragroup Marginalisation and Its Associations with Mental and Social Well-Being in Australian Sexual Minority Men (Supervisors Dr Amanda Duffy and Prof Melanie Zimmer-Gembeck, Griffith University)

    • Honours Thesis (2019):
      “Effects of Online Writing Tasks on Self-Attitudes in Same-Sex Attracted Men” (Supervisor Dr Sia Bandarian-Balooch, Griffith University)

    Peer-reviewed publications:

    • Dellers, L. Y. E., Duffy, A. L., & Zimmer-Gembeck, M. J. (2025). Sexual minority men’s mental health: Associations with gay community intragroup marginalization beyond heterosexist discrimination. Journal of Homosexuality, 1–31. https://doi.org/10.1080/00918369.2025.2485157

    • Dellers, L. Y. E., Duffy, A. L., & Zimmer-Gembeck, M. J. (2024). Manifestations and harms of intragroup marginalization within the male gay community: A qualitative study of gay and bisexual men. Psychology of Sexual Orientation and Gender Diversity, Advance online publication. https://doi.org/10.1037/sgd0000724

    • Thai, M., & Dellers, L. Y. E. (2019). Rejecting Equality: Psychological Differences Between Australian Sexual Minority Men Voting “Yes,” Voting “No,” or Abstaining From Voting on the Legalization of Same-Sex Marriage. Psychology of Sexual Orientation and Gender Diversity, 7 (2), 186–196. https://doi.org/10.1037/sgd0000368

    Conference presentations:

    • Annual Society of Australasian Social Psychologists (SASP) annual conference 2022 (Adelaide, SA)
      Title of presentation: “Social Interactions in the Gay Community”

    • Annual Society of Australasian Social Psychologists (SASP) 2019 (Sydney, NSW)
      Title of presentation: “Rejecting equality: Psychological differences between Australian same-sex attracted men voting “Yes”, voting “No”, or abstaining from voting on the legalisation of same-sex marriage”

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