Lou had a 50-year career as a psychiatrist. He served tirelessly as the founder of two outpatient trauma clinics — Trauma Recovery Institute (1996-2006) and Intensive Trauma Therapy (2006 to present). He and his wife, Linda Gantt, developed the Instinctual Trauma Response model from early clinical trials at Chestnut Ridge Hospital at West Virginia University (Morgantown, West Virginia) and the Louis A. Johnson Veterans Administration Medical Center (Clarksburg, West Virginia).

In the 1970s, Lou had a private practice in psychiatry in Laurel, Maryland. He became active in the politics of mental health and was instrumental in getting the state of Maryland to pass a law requiring that general hospitals have psychiatric units. This was at a time when even the most prestigious mental health facility in the state was little more than a warehouse for seriously disturbed psychiatric patients.

After moving to West Virginia in 1979, Dr. Tinnin served as the medical director of a community mental health center. In 1984, he joined the faculty of the Department of Behavioral Medicine and Psychiatry in the School of Medicine at West Virginia University, serving as associate professor and professor. He began pursuing knowledge about post traumatic stress disorder (PTSD), an area that interested few people at the time.

In 1992, Lou developed a Fellowship in Psychotraumatology in conjunction with WVU and the VA Medical Center. It was then that he began doing research on how to process traumatic events without requiring a person to relive them. After retiring from WVU in 1996 with the rank of professor emeritus, Lou established his own clinic [the Trauma Recovery Institute (TRI)] where he could try out his ideas about innovative and brief trauma treatment. Linda worked with him at TRI as art therapist and later as executive director. In 2006, Lou retired a second time and closed TRI. However, he served as a psychiatric consultant for Linda as she set up Intensive Trauma Therapy.

Lou wrote a number of professional papers and made over 200 national and international presentations. He and Linda authored The Instinctual Trauma Response and Dual Brain Dynamics (2014). Although Lou knew his health was failing, he continued to work to within two weeks of his death on several projects including some innovative tools incorporating a web site and mobile apps for trauma treatment available to survivors and therapists alike (www.TraumaTherapyApp.com).

Some of the cases Lou saw in medical school stayed with him for his whole life. He questioned the received wisdom of older doctors who did not comprehend how invasive medical procedures in very young children could be traumatic. These doctors assumed the child’s nervous system was too immature to feel pain and, even if the child did feel it, he or she would not remember it. His clinical observations impelled Lou to work out procedures for dealing with early memories that were nonverbal but resulted in long-lasting and disturbing symptoms.

Lou was a strong supporter of the mental health emancipation and recovery movements. He was passionate about learning all he could about scientific ways to treat trauma. Many times he said that he wished he were like General Motors and could recall his patients when he learned something new.