Psychological Assessment & Treatment

Strength-based and collaborative services for children, adolescents and adults

Psychological Assessment

Psychological Assessment

A comprehensive evaluation of attention and executive functions (possible ADHD symptoms), mood and anxiety symptoms, social and trauma-related concerns. This assessment will help understand what is going well in your (or your child’s) life, what has been challenging and why, spark hope, and provide a great plan of possible next steps.

Psychological Assessment

Psychoeducational Assessment

When there are specific learning issues, a Psychological Assessment can be expanded to include in-person testing with a psychologist. This assessment will help understand how your (or your child’s) brain thinks and learns, through careful evaluation of cognitive and thinking skills, memory, academic abilities and language, and other psychological processes that can impact learning.

ADHD Coaching & Psychotherapy

ADHD Coaching and Psychotherapy

Individual, online sessions for adults. I integrate kindness and empathy with research-supported practice, including ADHD coaching, Cognitive Behavioural Therapy (CBT), attachment-informed and integrative psychotherapy, and Cognitive Processing Therapy (for PTSD).

All psychological and psychoeducational assessments, ADHD coaching and psychotherapy sessions are provided by a psychologist

Diana Mandeleew

Dr. Diana Mandeleew, Psy. D., C. Psych. (she/her)

Clinical Psychologist

I have over 20 years of assessment, treatment and clinical experience in a variety of settings, collaborating with psychiatrists and other medical and mental health professionals. 

I approach each individual in a collaborative and kind way. I want to hear and understand you. Together, we will explore your strengths, identify areas of difficulties, understand what is happening, and figure out how you can move towards greater wellness.  


Ontario Psychological Association

Contact Us

For more information or to book a free consultation with a psychologist

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Psychological assessments, ADHD coaching and psychotherapy are conducted online, across Ontario. Psychoeducational assessments are conducted at our two testing centres (by appointment only).

York/Vaughan: 1520 Steeles Avenue West, Suite 101A, Vaughan, Ontario, L4K 3B9

Durham/Uxbridge: 29 Toronto Street South, Suite 107, Uxbridge, Ontario, L9P 1V9

In case of an emergency, call 911 or visit your nearby emergency department.