Dr. John William O’Riordan – Psychiatrist | Mississauga, ON

Dr. John William O'Riordan is a dedicated Psychiatrist specializing in the diagnosis, treatment, and prevention of a wide range of mental, emotional, and behavioral disorders in adults, and may see older adolescents for certain conditions. Practicing at a mental health clinic or hospital department in Mississauga, ON, he is a key member of the local mental healthcare community. His practice is committed to adhering to the standards and ethical guidelines set by the College of Physicians and Surgeons of Ontario (CPSO). He provides comprehensive psychiatric care, including diagnostic assessment, medication management, and psychotherapeutic interventions for a variety of conditions such as mood disorders, anxiety disorders, and psychotic disorders. Dr. O'Riordan's approach emphasizes personalized care aimed at fostering recovery and resilience. Patients can expect a confidential and respectful environment where their mental health concerns are listened to carefully, and treatment plans are tailored to their unique needs.

He graduated with a Medical Degree from the University of Dublin in Ireland and has been practicing as a Psychiatrist for over 38 years, since 1986. His extensive experience has allowed him to develop a deep understanding of complex psychiatric conditions and their management. Recognized as a Royal College of Physicians and Surgeons of Canada (RCPSC) Specialist, Dr. O'Riordan maintains a commitment to ongoing professional development and adherence to best practices in mental health care. His certifications and clinical expertise underpin his ability to deliver high-quality psychiatric services, ensuring patients receive evidence-based and compassionate treatment.

Dr. O'Riordan's clinical philosophy centers on collaborative care, emphasizing patient empowerment through education and understanding. He believes that establishing a strong therapeutic alliance built on trust and respect is fundamental to effective treatment. Incorporating the latest evidence-based approaches, he strives to create a supportive environment where patients feel safe to explore their concerns and work towards improved mental health and well-being. Fluent in English, Dr. O'Riordan is dedicated to providing accessible and attentive care to residents of Mississauga, fostering a pathway to recovery through personalized and respectful engagement.

Dr. John O'Riordan provides assessment and treatment for a wide spectrum of mental health conditions, including:

Anxiety, OCD & Trauma-Related Disorders

• Panic Disorder (with or without Agoraphobia): Recurrent, unexpected panic attacks (sudden periods of intense fear) and persistent concern about having additional attacks or their consequences.
• Specific Phobias (e.g., heights, animals, injections): Intense, irrational fear of a specific object or situation that poses little or no actual danger.

Other Psychiatric Conditions & Focus Areas

• Somatic Symptom Disorder & Illness Anxiety Disorder: Characterized by significant focus on physical symptoms (Somatic Symptom Disorder) or preoccupation with having or acquiring a serious illness (Illness Anxiety Disorder), causing major distress or functional impairment.
• Eating Disorders (Anorexia Nervosa, Bulimia Nervosa, Binge Eating Disorder - psychiatric co-management): Serious conditions related to persistent eating behaviors that negatively impact health, emotions, and ability to function, often requiring multidisciplinary care including psychiatric management.

Substance-Related & Addictive Disorders (Dual Diagnosis)

• Alcohol Use Disorder: A chronic relapsing brain disorder characterized by an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences.
• Stimulant Use Disorder (e.g., Cocaine, Amphetamines): Problematic pattern of stimulant use leading to impairment or distress.
• Dual Diagnosis (Co-occurring Substance Use Disorder & Other Mental Illness): The simultaneous presence of a substance use disorder and one or more other psychiatric disorders (e.g., depression, anxiety, bipolar disorder, schizophrenia).

This list is not exhaustive. Effective mental health care is highly personalized. Please consult with Dr. John O'Riordan for an accurate diagnosis and tailored treatment plan.

• Second Opinion Consultations for Complex Psychiatric Cases: Providing expert second opinions on challenging diagnoses, treatment-resistant conditions, or complex psychopharmacological management plans.
• Medication Management for ADHD in Adults & Children/Adolescents: Prescription and monitoring of stimulant and non-stimulant medications for Attention-Deficit/Hyperactivity Disorder across the lifespan.
• Comprehensive Psychiatric Assessment & Diagnostic Evaluation: In-depth clinical interview to assess mental health status, including review of psychiatric and medical history, family history, psychosocial factors, symptom patterns, and formulation of a multiaxial diagnosis according to DSM/ICD criteria.
• Augmentation & Combination Strategies for Treatment-Resistant Conditions: Employing advanced psychopharmacological strategies, including combining medications or adding augmenting agents, for individuals who have not responded adequately to initial treatments.
• Cognitive Behavioral Therapy (CBT): A structured, goal-oriented psychotherapy that helps individuals identify and change negative thought patterns and behaviors contributing to mental health problems like depression, anxiety, and OCD.
• Neuropsychiatric Evaluation & Cognitive Assessment (Initial Screening/Referral): Initial assessment of cognitive function and neuropsychiatric symptoms, with referral for detailed neuropsychological testing if indicated, to differentiate psychiatric from neurological conditions.

Note: This list provides a general overview. Treatment approaches are highly individualized. Please discuss with Dr. O'Riordan for care relevant to your specific mental health needs.

All psychiatric services are provided in accordance with the standards of practice set by the College of Physicians and Surgeons of Ontario (CPSO) and relevant psychiatric care guidelines. Contact the clinic or your referring physician regarding new patient intake and referral processes.

Dr. O'Riordan's practice is situated within a well-equipped mental health facility located in the Sheridan Homelands, Erindale South neighborhood of Mississauga. The setting is conveniently accessible from the Toronto Pearson International Airport (YYZ) area and Meadowvale Business Park, making it suitable for patients coming from various regions. Public transit options include MiWay (Mississauga Transit), providing easy access to the location. The facility is wheelchair accessible and aims to provide a comfortable and private environment for all patients. Paid parking options are conveniently located nearby, some with direct building access, ensuring ease of visitations. The environment is discreet, welcoming, and designed to foster a sense of safety and confidentiality for patients seeking mental health support.

Are psychiatric consultations and treatments with O'Riordan, a Psychiatrist, covered by Ontario Health Insurance Plan (OHIP) in ON?

Medically necessary consultations, diagnostic assessments, and medication management provided by a licensed Psychiatrist like O'Riordan are generally covered by Ontario Health Insurance Plan (OHIP) in ON when a referral from a family doctor is in place. Coverage for psychotherapy services provided by a psychiatrist can vary; some provinces cover it, while others may have limitations or it may be part of hospital-based programs. Specific medications may also require special authorization or be subject to formulary restrictions. It's crucial to discuss coverage specifics for therapy or any specialized treatments with O'Riordan's office or Ontario Health Insurance Plan (OHIP).

Do I need a referral to see O'Riordan, a Psychiatrist?

Yes, a referral from your family physician or another medical doctor (e.g., a pediatrician for child psychiatry, or an ER physician for urgent assessment) is almost always required to see a Psychiatrist such as O'Riordan for services covered by the provincial health plan. Mental health conditions often benefit from initial assessment by a primary care provider who can determine the need for specialist psychiatric care. The referral ensures coordinated care, appropriate triaging, and transfer of relevant medical history.

What is the main difference between a Psychiatrist like O'Riordan and a Psychologist?

The main difference is that a Psychiatrist, like O'Riordan, is a medical doctor (MD) who has completed medical school and then specialized residency training in psychiatry. Because they are physicians, psychiatrists can diagnose mental health conditions, prescribe and manage psychotropic medications, and provide various forms of psychotherapy. They can also order medical tests to rule out physical causes of psychiatric symptoms. A Psychologist typically has a doctoral degree (PhD or PsyD) in psychology and is trained in psychological assessment, diagnosis, and providing psychotherapy (talk therapy). Psychologists generally cannot prescribe medication in Canada, though they often work closely with psychiatrists or family doctors who do.

When should someone consider a referral to a Psychiatrist like O'Riordan?

A referral to a Psychiatrist like Dr. O'Riordan is typically considered when mental health symptoms are severe, persistent, complex, or not responding adequately to initial treatments provided by a family doctor or therapist. This can include: thoughts of suicide or self-harm; severe depression or mania; psychosis (hallucinations, delusions); debilitating anxiety or panic attacks; complex PTSD; severe OCD; suspected bipolar disorder or schizophrenia; treatment-resistant depression; or when medication management by a specialist is indicated. Psychiatrists are also consulted for diagnostic clarification and comprehensive treatment planning, especially for co-occurring conditions.

How is confidentiality handled in psychiatric care?

Confidentiality is a cornerstone of psychiatric care. Information you share with Dr. O'Riordan and his team is kept private and protected by law and professional ethics. This means your information will not be disclosed to anyone without your explicit consent, except in very specific situations where there is a legal obligation or an immediate risk of serious harm to yourself or others (e.g., imminent risk of suicide or homicide, child abuse, or a court order). Dr. O'Riordan will typically discuss the limits of confidentiality with you at the beginning of your treatment.

Suite D, 2695 North Sheridan Way
Mississauga, ON L5K 2P8

Phone: (905) 362-3508

The facility is wheelchair accessible and aims to provide a comfortable and private environment for all patients.

Dr. O'Riordan is a licensed Psychiatrist regulated by the College of Physicians and Surgeons of Ontario (CPSO) under the Regulated Health Professions Act, 1991 and Medicine Act, 1991 in ON. A referral from a family physician or another medical doctor is typically required for consultations with Dr. O'Riordan for services covered by the provincial health plan.

Verify registration with the College of Physicians and Surgeons of Ontario (CPSO): https://doctors.cpso.on.ca/DoctorDetails/ORiordan-John-William/0040859-54835