Find the provider that best suits your needs.
Robert Summerour, M.D.
Dr. Robert Summerour, M.D., graduated from Loma Linda University School of Medicine in 1971 and completed his Psychiatry Residency at the Loma Linda University School of Medicine in 1974. He is board certified in Psychiatry by the American Board of Psychiatry and Neurology. In 1982, Dr. Summerour founded the Riverside Psychiatric Medical Group. He treats adults of all ages and specializes in the management of complex behavioral health problems.
Education & Training
MD, Loma Linda University School of Medicine – 1971
Psychiatry Residency, Loma Linda University School of Medicine – 1974
Board Certified in Psychiatry, American Board of Psychiatry and Neurology- 1980
Clinical Expertise
Management of complex behavioral health problems
Mood and anxiety disorders
Long-term psychopharmacology
Treatment-resistant depression and bipolar disorder
Adult ADHD
Psychiatric care across the lifespan
Treatment Philosophy
With five decades of experience, I remain committed to truly listening to each patient and crafting individualized treatment plans that respect personal history, values, and goals. My approach combines careful medication management with practical, evidence-based strategies—always delivered with patience, respect, and a focus on long-term wellness.
Personal Note
In 1982, I founded Riverside Psychiatric Medical Group with a simple belief: every person deserves high-quality, compassionate psychiatric care close to home. It remains a privilege to serve this community alongside an outstanding team of colleagues.
Meet Our Providers
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Dr. Antonius “Tony” Brandon is a seasoned clinical psychologist and neuropsychologist with over 45 years of experience in private practice, specializing in comprehensive psychological evaluations and therapy for children, adolescents, and families. Known for his warm, insightful approach, he has helped countless individuals and families navigate challenges with humor, empathy, and evidence-based strategies since joining Riverside Psychiatric Medical Group.
Education & Training
PhD in Clinical Psychology, United States International University (USIU; now Alliant International University) – 1980
MS in Clinical Psychology and Marriage and Family Therapy, Loma Linda University
Post-Doctoral Certification in Human Sexuality, University of California, Los Angeles (UCLA)
Post-Doctoral Certification in Clinical Neuropsychology, Fielding Graduate University (formerly Fielding Institute)
Licensed Psychologist, California Board of Psychology
Licensed Marriage and Family Therapist, California Board of Behavioral Sciences
Clinical Expertise
Psychological evaluations and general assessments
Neuropsychological assessments for cognitive and behavioral concerns
ADHD evaluations and management
Child and adolescent psychology
Family systems therapy and marital counseling
Psychodynamic psychotherapy
Behavioral and cognitive behavioral therapy (CBT)
Dialectical behavior therapy (DBT) and brief problem-solving therapy
Mindfulness-based interventions
Telemedicine for psychological services
Treatment Philosophy
With decades of experience across all age groups—but a special focus on children and adolescents—I integrate a variety of modalities, from cognitive behavioral therapy and family systems work to dialectical behavior therapy and mindfulness, to create tailored paths to healing. My goal is to empower individuals and families with practical tools, fostering resilience and connection in a supportive, non-judgmental space. Patients often describe my sessions as insightful, kind, and unexpectedly humorous, helping to lighten even the toughest journeys.
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Yvette Chavez is a dedicated Licensed Marriage and Family Therapist with over 20 years of experience in mental health and more than 13 years in private practice. She provides compassionate individual, family, and group psychotherapy to culturally diverse children, adolescents, and adults, specializing in cognitive behavioral approaches to address developmental disorders, anxiety, mood disorders, psychosis, and substance abuse.
Education & Training
Master of Arts (MA) in Marriage and Family Therapy, Pepperdine University, Malibu, CA – 1999
Licensed Marriage and Family Therapist (LMFT), California Board of Behavioral Sciences
Clinical Expertise
Cognitive behavioral therapy (CBT) for anxiety, mood disorders, and substance abuse
Behavioral therapy and problem-solving therapy
Psychodynamic psychotherapy
Marital and family counseling
Psychological evaluations
Child and adolescent therapy (ages 5+)
Telemedicine for psychological services
Treatment Philosophy
Drawing from cognitive behavioral principles, I help clients identify and reframe unhelpful thought patterns to build resilience and achieve meaningful change. With a deep appreciation for cultural diversity, my sessions are collaborative and empowering, focusing on practical tools to manage symptoms and foster healthier relationships—whether working one-on-one, with families, or in groups. Patients often leave feeling understood, equipped, and hopeful.
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Dr. April Gustafson is a Psychiatric Mental Health Nurse Practitioner and the Clinical Coordinator at Riverside Psychiatric Medical Group. Her nursing journey began over 17 years ago—first spending 10 years as a Licensed Vocational Nurse providing round-the-clock support for children and adolescents with complex medical needs, then earning her RN, BSN, and DNP while raising a family. Through her own life challenges, she developed her ability to serve in psychiatry—and now brings deep empathy, clinical expertise, and a compassionate whole-person approach to those navigating mental health concerns, chemical dependency, and life’s trials.
Education & Training
Doctor of Nursing Practice (DNP), Loma Linda University School of Nursing – 2024
Bachelor of Science in Nursing (BSN), Loma Linda University – 2018
Board Certified Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC) Across the Lifespan, ANCC
IEHP Healthcare Scholarship Recipient, Inland Empire Health Plan (2020–2024)
Clinical Expertise
Substance use disorders & addiction recovery. Medication-Assisted Treatment (MAT)
Women’s mental health and perinatal psychiatry
ADHD across the lifespan
Management of mood, anxiety, psychotic and trauma-related disorders
Co-occurring medical and psychiatric conditions
Genomic (pharmacogenomic) testing for treatment optimization
Functional and integrative psychiatry
Treatment Philosophy
“I am honored to walk alongside each person on their healing journey. My goal is to empower patients with knowledge, practical tools, and personalized plans that treat the whole person—mind, body, and spirit—so they can achieve lasting recovery and wellness.”
A Little More About Me
My path to psychiatric nursing wasn’t a straight line—it was shaped by a decade of hands-on clinical pediatric care as an LVN, followed by personal struggles that showed me the transformative power of compassionate mental health support. That experience drives everything I do today, both with patients and behind the scenes as Clinical Coordinator.
About My Role as Clinical Coordinator
Dr. Gustafson keeps the practice running smoothly so our clinicians can focus on what they do best—caring for you.
“Throw her into the fire and she’ll come out like gold” – calm under pressure, resourceful, and always finding a way forward with a smile.” – Dr. Warren PetersResponsibilities include:
Provider recruitment, interviewing, and onboarding
Credentialing and insurance panel management
Prior authorizations and payer communications
Website design/maintenance and patient portal oversight
Compliance and quality initiatives
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Ariel Gonzalez, MSN, PMHNP-BC, is a board-certified Psychiatric Mental Health Nurse Practitioner committed to delivering compassionate, evidence-based mental health care. With a diverse clinical background and a person-centered philosophy, Ariel supports individuals in navigating complex psychiatric and emotional challenges with sensitivity, respect, and cultural awareness.
Education & Training
Master of Science in Nursing – PMHNP, Azusa Pacific University
Bachelor of Science in Nursing, Azusa Pacific University
Bachelor of Arts in Anthropology, California State University Long Beach
Board Certification: Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC)
Clinical Expertise
Mood and anxiety disorders
Trauma- and stressor-related disorders
ADHD assessment and treatment
Depression and bipolar disorders
Behavioral and emotional dysregulation
Crisis assessment and stabilization
Psychiatric care with co-occurring medical complexity
Professional Background
Ariel’s clinical experience spans inpatient psychiatry, emergency and observation units, and medical-surgical, neurological, and cardiovascular settings. This breadth of exposure strengthened their diagnostic accuracy, crisis-management skills, and ability to care for patients with complex psychiatric and medical needs.
Before transitioning into nursing and advanced practice, Ariel spent nearly a decade working closely with developmentally delayed individuals, providing one-on-one support, behavioral guidance, and skill-building interventions. This experience fostered a deep appreciation for individualized care, patience, and meeting each person where they are in their journey.
Treatment Philosophy
Ariel believes mental health care is most effective when patients feel heard, understood, and empowered. Their approach blends evidence-based psychopharmacology with trauma-informed principles, emphasizing collaboration, cultural responsiveness, and individualized treatment planning. Ariel is committed to fostering a therapeutic environment where patients feel safe, supported, and equipped to achieve long-term stability and personal growth.
Languages Spoken
• English (fluent)
• Spanish (fluent)
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Dr. Offenstein is a licensed clinical psychologist with over 50 years of experience helping adults uncover the root causes of emotional challenges and relational difficulties, empowering them to achieve greater fulfillment in work, relationships, and daily life through insightful, transformative therapy.
Education & Training
PhD in Clinical Psychology, Claremont Graduate University – 1973
Additional training in Psychoanalytic Psychotherapy, Newport Psychoanalytic Institute
Clinical Expertise
Psychological evaluations and general assessments
Neuropsychological assessments
ADHD evaluations
Psychodynamic psychotherapy
Cognitive behavioral therapy (CBT)
Behavioral therapy
Problem-solving therapy
Marital and family counseling
Telemedicine for psychological services
Treatment Philosophy
Life's events shape how we experience and respond to the world, often creating barriers to our potential for satisfaction and growth. In my practice, I guide adults in exploring these influences, learning to reframe thoughts and reactions to foster meaningful change. With a foundation in psychodynamic principles and evidence-based techniques, sessions are collaborative, focused on building self-awareness, resilience, and practical strategies—always in a supportive environment that honors your unique journey.
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Jessica Millan is a doctorally prepared, board-certified Psychiatric–Mental Health Nurse Practitioner with over a decade of diverse clinical experience spanning psychiatric care, chemical dependency, medical-surgical, oncology, and transplant nursing. She provides comprehensive psychiatric evaluations, medication management, and patient-centered care for adults at Riverside Psychiatric Medical Group. Jessica integrates her broad medical background with a holistic, whole-person approach to mental health, emphasizing coping strategies, stress management, relationship health, and supportive counseling. She values collaboration with therapists and families to promote meaningful, whole-person healing.
Education & Training
Doctor of Nursing Practice (DNP), Psychiatric-Mental Health Nurse Practitioner track- Chamberlain University
Master of Science in Nursing (MSN), Azusa Pacific University
Bachelor of Science in Nursing (BSN)
Board Certified Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC), ANCC
Clinical Expertise
Mood and anxiety disorders
Trauma- and stressor-related disorders
ADHD evaluation and treatment
Depression and bipolar disorders
Schizophrenia-spectrum and other psychotic disorders
Behavioral and emotional dysregulation
Psychiatric care involving co-occurring medical conditions
Treatment Philosophy
My approach is rooted in empathy and evidence-based care, recognizing that mental health challenges often intersect with physical health and life transitions. Drawing from my diverse nursing background, I collaborate closely with patients to develop personalized plans—integrating medication management, genomic insights, and supportive strategies—to promote recovery, resilience, and overall well-being in a safe, non-judgmental space.
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Dr. Elizabeth Fuss is a clinical psychologist focused on supporting children, adolescents, and adults in navigating mental health challenges using compassionate, evidence-based care.
Education & Training
Antioch University New England – 2021
Psychology Residency, University of Utah Huntsman Mental Health Institute - 2021 - 2022
Clinical Expertise
Children and adolescents
Autism Spectrum Disorder
Mood & anxiety disorders
Early childhood mental health (ages 6 & under)
Trauma-informed treatment
Treatment Philosophy
I utilize a collaborative, client-centered approach, relying on consistent feedback to optimize the therapeutic process. With children and adolescents, my focus is on creating a welcoming, positive, and enjoyable space to encourage openness and facilitate the most effective engagement in sessions.
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Andrea LeNeve is a compassionate Licensed Marriage and Family Therapist with over 35 years of dedicated experience in mental health. At Riverside Psychiatric Medical Group, she specializes in helping adults and families reduce symptoms of depression and anxiety, fostering tools and strategies to thrive in everyday life and build resilient relationships.
Education & Training
Master’s Degree in Marriage and Family Therapy
Licensed Marriage and Family Therapist (LMFT), California Board of Behavioral Sciences
Extensive postgraduate training in evidence-based therapeutic modalities
Clinical Expertise
Depression and mood disorders
Anxiety and stress management
Family and marital counseling
Trauma-informed care
Group and individual psychotherapy
Telemedicine services
Treatment Philosophy
With a career spanning more than three decades, I believe true healing comes from understanding the unique stories and strengths of each individual and family. My approach is collaborative and empowering, blending practical coping skills with deeper relational work to help clients not just manage challenges but embrace joy and connection in their daily lives, creating lasting change in a safe, supportive space.
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Karen Meske is a board-certified Psychiatric-Mental Health Nurse Practitioner with over 21 years of nursing experience, including 14 years in mental health settings at renowned institutions like Cedars-Sinai, UCLA, and Huntington Hospital. Specializing in adults 18 and older, she provides comprehensive psychiatric evaluations, medication management, and holistic care at Riverside Psychiatric Medical Group, complemented by her volunteer work with a non-profit focused on substance abuse and dual diagnoses.
Education & Training
Doctor of Nursing Practice (DNP), Chamberlain University- 2024
Master of Science in Nursing (MSN), Chamberlain University
Bachelor of Science in Nursing (BSN), Chamberlain University
Initial Nursing Diploma, Nursing Program in Germany
Board Certified Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC), ANCC
Clinical Expertise
Psychiatric evaluations and diagnostic assessments
Medication management for mood, anxiety, and psychotic disorders
Substance use disorders and dual diagnoses
Genomic (pharmacogenomic) testing for personalized treatment
Electroconvulsive therapy (ECT) support and recovery
Crisis intervention in emergency and inpatient settings
Telemedicine for psychiatric care
Treatment Philosophy
Having honed my skills in high-acuity environments like inpatient psych units and ERs, I approach care with empathy, precision, and a commitment to whole-person wellness. My philosophy centers on collaborative partnerships—listening deeply to your experiences, integrating evidence-based medication strategies with lifestyle insights, and drawing on genomic tools when helpful to optimize outcomes. Whether managing chronic conditions or navigating life's transitions, I aim to empower you toward stability, clarity, and renewed purpose.
Languages Spoken
English (fluent)
German (conversational)
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Dr. Sukh Dev Singh Khalsa is a board-certified Psychiatric-Mental Health Nurse Practitioner with over 30 years of experience in mental health, specializing in psychiatric evaluations, medication management, and personalized treatment plans for adolescents and adults (ages 13+) facing anxiety, depression, PTSD, substance use disorders, ADHD, and more. He blends evidence-based practices with deep compassion to support lasting recovery and well-being at Riverside Psychiatric Medical Group.
Education & Training
Doctor of Nursing Practice (DNP), Loma Linda University School of Nursing, Loma Linda, CA – 2016
Master of Science in Nursing (MSN), Psychiatric-Mental Health Nurse Practitioner Program, Azusa Pacific University, Azusa, CA – 2011
Master of Business Administration (MBA), Emphasis in Health Care Management, University of Phoenix, West Los Angeles Campus – 2009
Board Certified Adult Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC), ANCC
Clinical Expertise
Mood and anxiety disorders
Trauma and PTSD
ADHD evaluation and management
Substance use disorders and addiction recovery
Women’s mental health and perinatal psychiatry
Eating disorders
Telemedicine for psychiatric care
Treatment Philosophy
“My mission is to provide personalized, judgment-free psychiatric care rooted in compassion, clinical excellence, and genuine human connection. Every patient deserves to feel heard, supported, and empowered on their journey to healing.”
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Dr. Shirlynn Lindrum is a doctorally prepared, board-certified Psychiatric-Mental Health Nurse Practitioner who brings a rare depth of experience—from bedside nursing in crisis settings to advanced practice care. With over seven years as a registered nurse on inpatient psychiatric units, chemical dependency detox, telemetry, and psychiatric urgent care, she delivers whole-person, compassionate psychiatric care to adolescents and adults.
Education & Training
Doctor of Nursing Practice (DNP), Psychiatric-Mental Health Nurse Practitioner track – Loma Linda University School of Nursing, 2024
Bachelor of Science in Nursing (BSN) – Loma Linda University School of Nursing, 2018
Board Certified Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC), ANCC
Certifications: BLS, ACLS, Non-Violent Crisis Intervention
Clinical Expertise
Medication management for mood, anxiety, psychotic, and trauma-related disorders
Adolescent and adult psychiatry
Substance use disorders and Medication-Assisted Treatment (MAT)
Crisis intervention and de-escalation
Pre- and post-care for electroconvulsive therapy (ECT)
Co-occurring medical and psychiatric conditions
Telepsychiatry
Treatment Philosophy
I believe healing begins when patients feel truly seen and safe. My approach combines evidence-based psychopharmacology with supportive therapy, trauma-informed care, and practical coping strategies tailored to each person’s story. Having worked in some of the most acute psychiatric settings, I understand that mental health challenges rarely happen in isolation—my years on the hospital floor taught me to listen carefully, respond calmly, and collaborate across disciplines to keep patients safe and moving forward.
Join Our Team
We’re growing and seeking passionate professionals to join our dedicated team!
Now Hiring:
Psychiatrists
Psychologists
Licensed Marriage and Family Therapists
If you’re committed to making a difference in mental health care, we’d love to hear from you! Please send your resume/CV to rivpsych1@hush.com
