Meet our team


Darin Cairns 
Clinical Psychologist | Clinic Director

Darin Cairns has over 17 years experience in treating children, adults and families for a range of psychological disorders. He has specialised in emotional, neurological and developmental disorders. Clinically, Darin has expertise in child, adolescent, family therapy and developmental disorders such as autism spectrum disorders. He also has extensive experience in adult mood disorders and works as a single expert witness. 

Darin is well known for his work with children, adolescents and adults with Autism Spectrum Disorders. Darin has set up award winning early intervention services in Western Australia for children with Autism Spectrum Disorders and related conditions. He was initially trained in Applied Behaviour Analysis (ABA), Clinical Behaviour Analysis and Functional Analytic Psychotherapy. After many years working with developmental specialists and clinicians his frustration at not being able to bridge the gap from ABA to complex behavioural and emotional domains lead him to Relational Frame Theory (RFT). He has since applied Relational Frame Theory (RFT) to hundreds of developmental programs for children with Autism Spectrum Disorders and special needs and continues to practice clinically using therapies developed from RFT such as Acceptance and Commitment Therapy (ACT) and other third wave Cognitive Behavioural Approaches.  

Darin has lectured at the tertiary level and has provided over 150 training courses to a wide range of populations in the medical, health and public settings.  He is a sought after speaker in the use of evidence based practice to promote psychological wellbeing and development around the world having been invited to speak in the UK, Europe, the US and most of Australia.

Behavioural & Developmental Therapists

Our early intervention behavioural and developmental therapists are professional and committed people who are dedicated to assisting families and children to reach their potential and goals in life. We provide behavioural and developmental therapists to most suburbs around the Perth Metropolitan area including the eastern, western, northern and southern suburbs.


Our therapists have all been through our comprehensive and intensive training program. They all receive ongoing regular supervision and support and are committed to long-term therapy with the families they work with. Our therapists have acquired skills training in (1) Pivotal Repose Training (2) Natural Environmental Training (3) Applied Behaviour Therapy (4) Independent, paired or group Social Skills Training and (5) Shadowing in day-cares, Kindergartens and Primary School settings. Our team members have different educational experiences. Some of our therapists are studying towards a university degree in Speech Pathology, Clinical Psychology, or Occupational Therapy. Some already hold a degree and for others, a role as a behavioural and developmental therapist is their chosen career as result of extensive experience in the field prior to working with us.


The behavioural and developmental therapists all share common traits of patience, problem solving abilities, flexibility, a sense of humour and a positive outlook.


Sharon Jeyabalan
Clinical Psychologist Registrar


Sharon Jeyabalan is a Psychologist, registered with the Psychology Board of Australia, and a Clinical Psychologist Registrar who has over 7 years experience working with children and families with a variety of needs. Sharon recently completed her Masters in Clinical Psychology and completed placements in the areas of early intervention services for adolescents as well as children with trauma and attachment difficulty backgrounds. Sharon was trained to utilise a range of assessment tools including cognitive and educational. Sharon’s research project was to examine the effectiveness of an Acceptance Commitment Therapy (ACT) approach for children with high levels of anxiety. She conducted group therapy sessions with children and their parents, following a protocol she designed under the supervision of Mr Darin Cairns, Clinical Psychologist and Director of The Charles Street Clinic.

At The Charles Street Clinic, Sharon has years of experience as a Developmental and Behavioural Therapist for children with Autism Spectrum Disorders. She works closely with parents and schools utilising a collaborative, systemic approach to the social, emotional and behavioural development of her clients.

Sharon works with children and families, as well as adults, on a range of presenting difficulties including anxiety, stress, depression and selective mutism. She also has experience working with adolescents with complex needs and has a keen interest in this area, particularly trauma. Sharon adopts principles from Applied Behaviour Analysis (ABA), attachment theory, functional analysis and Acceptance and Commitment Therapy (ACT).

Katherine Smith
Registered Psychologist

Katherine Smith is a Psychologist, registered with the Psychology Board of Australia, with over 10 years experience working with children, adults and families with a variety of needs. Katherine also has experience in various positions working within the Department of Child Protection, the Department of Corrective Services and within supported accommodation for individuals with psychiatric disabilities, adopting a rehabilitative approach.

At The Charles Street Clinic, Katherine has worked in a number of roles. Having years of experience as a Developmental and Behavioural Therapist with children with Autism Spectrum Disorders Katherine provided Case Management services for the Early Intervention Program. In this role Katherine worked closely with parents and schools promoting empowerment in parents and encouraging a collaborative approach to the social, emotional and behavioural development of her clients.

As a Registered Psychologist, Katherine works together with children, adolescents and families as well as adults on a range of presenting difficulties including mood disorders, selective mutism and anxiety disorders. Katherine is trained in the provision of assessments for learning disability including dyslexia, as well as cognitive assessments, and assessments for ADHD.

Using evidence-based assessments, treatments and interventions, Katherine adopts principles from Applied Behaviour Analysis (ABA), Functional Analysis and Acceptance and Commitment Therapy (ACT).

Rachel Gallagher
Educational and Developmental Psychologist | Clinical Psychologist | Clinic Director

Rachel Gallagher is an AHPRA endorsed Educational and Developmental Psychologist and Clinical Psychologist with over 18 years of experience working with children and adolescents with developmental disability. Rachel has expertise in the assessment and treatment of individuals with autism spectrum disorders, learning difficulties and special needs. She also specialises in children and adolescents with anxiety disorders. 


Rachel adheres to only assessments, treatments and interventions that are supported by evidenced based research promoting the best outcomes for her clients. 


Rachel is currently undertaking her PhD at Edith Cowan University and is examining predictors of depressive symptoms in adolescents with Autism Spectrum Disorders. 

Sian Newton
Medical Secretary

Sian has a strong back ground in customer service. Prior to her role at the Charles Street Clinic, Sian has worked as a medical secretary and receptionist for a number of obstetricians and gynaecologists in Perth, as well as Ear Nose and Throat surgeons. Sian is currently responsible for the day to day operations of the clinic. She will be happy to help you with any administration queries you may have.