Our Team

Thorntree Psychiatric Associates

Meet Our Compassionate Professionals

Our physicians at Thorntree Psychiatric Associates in Dallas, TX are either board-eligible or certified by the American Board of Psychiatry and Neurology. Each of them offers an initial comprehensive psychiatric evaluation, crafts an individualized treatment plan, and ensures regular follow-up care for all their patients.


Meet our team by scrolling below, and reach out to us when you feel ready to schedule with one of our providers.

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Thomas W. Lucas, M.D.

  • Adult and Geriatric Neuropsychiatry

    Dr. Thomas W. Lucas, an adjunct professor of psychiatry at the Texas A&M College of Medicine-Dallas, specializes in adult and geriatric neuropsychiatry. He holds certifications in Adult Psychiatry from the American Board of Psychiatry and Neurology.

     

    Dr. Lucas graduated from Oklahoma State University with a Bachelor's in Pre-Medical Sciences. He earned his Doctorate in Medicine at the University of Oklahoma College of Medicine, followed by an internship in neurology, internal medicine, and psychiatry. His residency in adult psychiatry took place at the Sheppard and Enoch Pratt Hospital, with affiliated studies in neurology at the Johns Hopkins University Hospital and School of Medicine.

     

    Dr. Lucas served as a medical officer in the United States Army European Command and had a successful army reserve career, including service as a special operations medical officer in the 12th Special Forces Group (Airborne). He completed his military service with the rank of lieutenant colonel.

     

    In his academic roles, Dr. Lucas has been recognized for his exceptional teaching, receiving the Gordon H. Deckert Chairman's Award for Sustained Excellence in Medical Teaching. He has served as hospital medical director at multiple psychiatric facilities and as the adult psychiatric intensive unit service chief at the Timberlawn Mental Health Center in Dallas.

     

    Dr. Lucas's clinical practice extends to Transcranial Magnetic Stimulation and nasal Esketamine (Spravato) for treatment-resistant depression. He continues his research in neuropsychiatry, with a focus on understanding neuro-inflammatory and electro-physiologic brain mechanisms underlying neuropsychiatric disorders, as well as the assessment and treatment of closed head injuries using cutting-edge technology.

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Pamela G. Hamilton, M.D.

  • General Adult Psychiatry

    Dr. Pamela G. Hamilton, an adjunct associate professor of psychiatry at the Texas A&M College of Medicine-Dallas Campus, specializes in anxiety, obsessive-compulsive disorder, and trauma-related stress disorders. She teaches these subjects in the Texas A&M Medical Student Psychiatric Clinical Clerkship, hosted by Thorntree Psychiatric Associates.

     

    Dr. Hamilton began her academic journey at the University of Oklahoma and later graduated from the University of Hawaii with a Bachelor of Arts in Psychology with Distinction. She completed her Doctorate in Medicine at the University of Oklahoma College of Medicine, where her accomplishments led to her election to the Alpha Omega Alpha Medical Honor Society. Her psychiatry residency took place at the University of Texas Southwestern Medical Center and the University of Oklahoma Medical Center. She also served as a clinical instructor in the University of Oklahoma Department of Psychiatry, teaching the Advanced Psychopharmacology course for senior residents.

     

    Certified in Adult Psychiatry by the American Board of Psychiatry and Neurology, Dr. Hamilton serves as the managing partner for Thorntree Psychiatric Associates. With 34 years of active clinical psychiatric practice in Dallas, she has a wealth of experience, including her role as the Director of the Adult Psychiatry Unit at the Haven Behavioral Hospital in DeSoto, TX. During this time, she also acted as a psychiatrist consultant and liaison to community physicians, focusing on the education and treatment of psychiatric disorders in women.

     

    Dr. Hamilton's practice encompasses general adult psychiatry, specializing in mood disorders (major depressive and bipolar disorders), anxiety disorders, post-traumatic stress disorders, obsessive-compulsive disorders, adjustment disorders, and attention deficit hyperactivity disorders. She maintains a particular interest in diagnosing and treating mood disorders in the peripartum period. Her treatment approach includes psychopharmacologic and psychotherapeutic measures, as well as modern treatment modalities like repetitive Transcranial Magnetic Stimulation and nasal Esketamine (Spravato).

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Mihaela V Stoica, M.D.

  • General Adult, Child, and Adolescent Psychiatry

    Dr. Mihaela V. Stoica practices general adult psychiatry and specializes in child and adolescent psychiatry. Her areas of expertise include mood disorders (depression and bipolar spectrum disorders), anxiety disorders, OCD, ADHD, autism spectrum disorder, disorders of infancy and childhood, tic disorders, and other neurodevelopmental conditions.

     

    Dr. Stoica earned her Doctorate in Medicine at the University of Medicine and Pharmacy "Carol Davila" in Bucharest, Romania, where she received government scholarships for excellent academic results throughout her medical school journey. She continued her medical education in the United States, completing her residency in adult psychiatry at Saint Louis University Hospital in a dual program encompassing neurology and psychiatry. After her residency, Dr. Stoica pursued a fellowship in Child and Adolescent Psychiatry at the University of Miami, Miller School of Medicine in Miami, FL.

     

    She holds dual certifications in Adult Psychiatry and Child and Adolescent Psychiatry, awarded by the American Board of Psychiatry and Neurology.

     

    In addition to her clinical practice, Dr. Stoica serves as an adjunct assistant professor of psychiatry at Texas A&M College of Medicine-Dallas Campus. She imparts her knowledge on disorders of childhood and adolescence and eating disorders in the Texas A&M Medical Student Psychiatric Clinical Clerkship, hosted by Thorntree Psychiatric Associates.

     

    Dr. Stoica is multilingual and proficient in English, Spanish, and Romanian.

     

    She maintains a keen interest in ongoing research, exploring novel therapeutic modalities for both adult and childhood illnesses. Her research areas encompass genetic testing, repetitive Transcranial Magnetic Stimulation, and nasal Esketamine (Spravato), all aimed at advancing the field of psychiatry and improving patient care.

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Richard Idell, M.D.

  • General Adult, Child, and Adolescent Psychiatry

    Dr. Idell holds a Doctorate in Medicine from the University of Texas Health Science Center in Houston. His extensive training includes a residency in adult psychiatry and a fellowship in child and adolescent psychiatry at the University of Miami Miller School of Medicine Psychiatry.

     

    Certified in both Adult Psychiatry and Child and Adolescent Psychiatry by the American Board of Psychiatry and Neurology, Dr. Idell imparts his knowledge as an adjunct assistant professor of psychiatry at Texas A&M College of Medicine - Dallas Campus. He plays a pivotal role in educating medical students during their rotations at Thorntree Psychiatric Associates.

     

    Dr. Idell's patient-centered approach spans all age groups, from children and adolescents to adults. Hailing from East Texas, he holds a particular interest in assisting patients with Treatment-Refractory Depression, a form of depression resistant to standard treatment. Dr. Idell's research focus encompasses inflammation, fibrinolysis, and resistant depression, all aimed at enhancing the well-being of individuals across generations, helping them lead happier and healthier lives.

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Taylor M. Herzog, M.D.

  • General Adult Psychiatry

    Dr. Taylor M. Herzog, M.D., specializes in general adult psychiatry, with expertise in anxiety and panic disorders, mood disorders (depression and bipolar disorders), OCD, PTSD, psychotic disorders, and ADHD.

     

    Dr. Herzog earned his M.D. from the Texas A&M College of Medicine, completing his clinical rotations in Dallas at Baylor University Medical Center. His residency in psychiatry took place at The University of Texas Medical Branch in Galveston, TX, where he was honored with the Thayer Award for Excellence in Teaching by the John P. McGovern Academy of Oslerian Medicine. He is currently board eligible for certification by the American Board of Psychiatry and Neurology in Adult Psychiatry.

     

    In addition to his clinical practice, Dr. Herzog serves as an adjunct assistant professor at the Texas A&M College of Medicine—Dallas Campus. He contributes to the education of medical students during their psychiatry rotation at the Thorntree Psychiatric Associates offices through teaching and lectures.

     

    Dr. Herzog's passion lies in exploring novel therapeutic modalities for both adult and adolescent illnesses. He remains dedicated to research and the implementation of innovative treatments, which include genetic testing, repetitive Transcranial Magnetic Stimulation, and nasal Esketamine (Spravato).

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Rija Siddiqui, M.D.

  • General Adult Psychiatry

    Dr. Rija Siddiqui specializes in general adult psychiatry with a strong focus on mood disorders (depression and bipolar spectrum disorders), anxiety and panic disorders, PTSD, OCD, psychotic disorders, and ADHD.

     

    She earned her Doctorate in Medicine at Texas A&M College of Medicine, graduating in the first quartile of her class with academic excellence in Pediatrics & Psychiatry. Dr. Siddiqui embarked on her medical journey by completing a general pediatrics residency at Children's Health/UT Southwestern Medical Center in Dallas, TX. During this period, she developed a keen interest in the mental health of children with chronic illnesses and how unexpected childhood events impact both parents and the family unit. While becoming a mother herself during her training, she recognized the critical need for maternal mental health support. Dr. Siddiqui's exceptional abilities led her to the prestigious position of chief resident in pediatrics as an assistant instructor of faculty at UT Southwestern.

     

    Following her chief year, she pursued a second residency in general adult psychiatry at UT Southwestern in Dallas. During her psychiatry residency, she completed a Women's Mental Health Concentration, with specific training in female gender-specific mental health issues. Her expertise includes peripartum psychiatry, medication management during pregnancy and breastfeeding, trauma, and eating disorders. Her research centers on women's mental health, including a focus on the motherhood experience for medical trainees and the role of cognitive behavioral therapy (CBT) in helping parents process the neonatal intensive care unit (NICU) experience. Dr. Siddiqui's therapy approach encompasses supportive, psychodynamic, and cognitive behavioral therapy, with a special interest in issues related to pregnancy, motherhood, parenting, and young individuals living with chronic medical conditions.


    Dr. Siddiqui is board-certified in General Pediatrics by the American Board of Pediatrics and is board eligible in General Adult Psychiatry by the American Board of Psychiatry & Neurology.

     

    She holds the role of Adjunct Assistant Professor of Psychiatry at Texas A&M College of Medicine, where she imparts her knowledge to medical students at the Dallas campus. Dr. Siddiqui's outstanding contributions have been recognized with the 2023-2024 Alexandra Symonds Award by the Association of Women Psychiatrists, honoring her significant contributions to promoting women's health and the advancement of women.

     

    Fluent in both English and Urdu, Dr. Siddiqui ensures effective communication with her diverse patient population.

Dr. Ronnie Pollard, M.D.

  • General Adult, Child, & Adolescent Psychiatry

    Dr. Ronnie Pollard, MD practices general adult psychiatry and specializes in child and adolescent psychiatry. His areas of expertise include mood disorders (depression and bipolar spectrum disorders), anxiety disorders, OCD, ADHD, autism spectrum disorder, tic disorders, and other neurodevelopmental conditions. He does Ketamine, TMS and ECT for treatment resistant conditions.


    Dr. Pollard earned his Doctorate in Medicine at the University of Texas Medical Branch in Galveston, Texas where he served on several honorary societies and was vice president of his freshman class and president of the service organization. He did his residency and fellowship in Adult & Child psychiatry at Baylor College of Medicine in Houston, Texas. He served as Chief Resident of Child Psychiatry. He was honored with both the Laughlin & Academic Fellowships during his residency. He was fortunate to work with Oprah Winfrey’s charity CIVITAS during his fellowship to help abused and neglected children. He had 5 publications during his medical training. He holds dual board certifications in Adult Psychiatry and Child and Adolescent Psychiatry, awarded by the American Board of Psychiatry and Neurology. 


    In addition to his clinical practice, Dr. Pollard has served as an adjunct assistant professor of psychiatry at Texas A&M College of Medicine Dallas Campus. He is currently a speaker for Teva Pharmaceuticals (Uzedy). He has been a speaker for Pfizer, Forest, GlaxoSmithKline and others during his career. 


    Dr. Pollard has been the Executive Medical Director at Green Oaks Hospital for over 5 years where he was also the Director of ECT having done over 5,000 treatments. He has served as the Division Chief of Psychiatry at Medical City Dallas for 5 years.


    He was featured in D Magazine in 2021 in an article on Pandemic parenting. He was the Principal Investigator in the COMP 006 study using psilocybin in treatment resistant depression.

Dr. Cassandra Jones

  • General Adult and Geriatric Psychiatry

    Dr. Cassandra Jones specializes in general adult psychiatry as well as geriatric psychiatry, which allows her to provide complex care for older adults. She has a passion for working with individuals with dementia as well as their caregivers through the unique transitions occurring in late life. 



    She earned her Doctorate in Medicine at the University of Texas Long School of Medicine in San Antonio where she was inducted into the Gold Humanism Honor Society. During medical school, Dr. Jones was drawn to psychiatry by a developed passion for supporting caregivers and witnessing the ways mental health impacts aspects of physical health. She completed general psychiatry residency at the University of Texas Southwestern Medical Center in Dallas, TX. Following residency, she completed a fellowship in Geriatric Psychiatry where she furthered her knowledge in mental health care for older adults. 



    Dr. Jones is board-certified in General Adult Psychiatry by the American Board of Psychiatry and Neurology. She holds the role of Adjunct Faculty of Psychiatry at the University of Texas Southwestern, where she helps to educate medical students, residents, and fellows to prepare future generations of physicians in caring for those with mental illness.