Dr Lawrence J. Seidman—affectionately called Larry—an eminent neuropsychologist, and beloved husband, father, grandfather, and brother, passed away suddenly on 7 September 2017. He was 67. He was due to give the first lecture at an NIMH meeting in Washington DC that morning, and had been his usual self, engaging in humorous conversation and showing pictures of his grandkids to his friends at the table. He suddenly felt ill, was taken to the hospital, and died about an hour later of a heart attack.

Larry was born and raised in New York city. He completed his undergraduate studies in psychology at City College of New York (CCNY) in 1971, an institution in which he had great pride. He received his doctorate at Boston University in 1980. He met Ilene Seidman, his wife of 46 years, when they were freshman at CCNY. They raised two children, Sarah, an historian and museum curator, and Josh, a lawyer. Before his death, Larry was blessed to meet his first grandson and first granddaughter.

Larry’s research career began with studies of the neuropsychology of temporal lobe epilepsy. He joined the faculty of Boston University Medical Center in 1980, and then moved to the Harvard Medical School (HMS) in 1985, where he continued for the rest of his career. Since 2002, he served as the Director of the ‘Center of Excellence for Clinical Neuroscience and Psychopharmacological Research’ at the Commonwealth of Massachusetts, Department of Mental Health-Harvard Medical School Department of Psychiatry Research Center. He became a full Professor at HMS in 2004, and served as the Vice-Chair of Psychiatry at the Beth Israel Deaconess Medical Center since 2005.

Larry’s work focused on cognitive deficits, which are a core aspect of schizophrenia. His 1983 integrative and theoretical review of the world literature (1920–1982) of brain dysfunction in schizophrenia, influenced the fields of psychology and psychiatry in contributing to an understanding that many psychiatric disorders have demonstrable neuropsychological deficits, a now well-accepted fact. Until the last days of his life, Larry worked closely with Allan Mirsky, his dissertation advisor and life-long mentor, with whom he was in the process of completing a magnum opus paper on the neuropsychology of schizophrenia. Larry’s painstaking work over the last three decades led to the characterization of the neural circuitry underlying cognitive deficits in schizophrenia, the delineation of their natural course, and the predictive value of ascertaining these deficits for early detection and intervention in psychotic disorders. In 2012, Larry published an important paper in PNAS on the dysfunction of the default network in schizophrenia, a highly cited paper that shed important light on the brain circuitry underlying psychosis and the familial risk for this syndrome. His research contributions extended to other neurodevelopmental disorders, such as ADHD, and his pioneering discoveries now help countless patients and clinicians learn how to detect this serious illness and intervene early.

Larry’s research and leadership contributions earned him close friendships with many like-minded scholars throughout the world, and many national and international laurels, including a Community Service Award by the International Schizophrenia Research Society in 2016. He was a member of the ACNP and published over 400 papers, several in high impact journals, and his work has been cited over 32 000 times. He was named by Thompson Reuters Science Watch as one of the ‘The World’s Most Influential Scientific Minds’ in 2013 and 2016.

In his role as the leader of the Commonwealth Research Center, Larry’s work was instrumental in the development of innovative clinical services for early course psychotic disorder patients, as well as for those at clinical high risk for these illnesses. Larry’s leadership was at national and international levels as well; he served on several NIMH committees, and at the time of his passing, he was the local chairman of the upcoming International Early Psychosis Association meeting in Boston. He continued to have an active clinical practice. He was an astute clinician, with over 30 years of experience as a clinical psychotherapist, and as a consultant psycho-diagnostician and neuropsychologist. His patients consistently remember him as the one doctor who always made ‘every one of them feel like a someone’ of significance.

For all his world renown, Larry treated everyone he encountered with dignity—his patients, mentees, colleagues, and collaborators. He was a generous and empathic man, with a disarming smile, and an open door to anyone who needed help or advice. He was a highly sought-after teacher and mentor, and scores of scientists and clinicians around the world owe their accomplishments to his tutelage. Many of his mentees are leading scientists, professors, or department heads. Weeks before his death, the Harvard Medical School awarded him the prestigious William Silen Lifetime Achievement Award for exceptional mentorship.

Larry will be remembered for having embraced every aspect of his life with the same zeal, whether it was talking about his children and beaming with pride over his grandchildren, cheering on the Celtics with his friends, discussing Bob Dylan, relishing a double espresso, or plumbing the deepest secrets of the mind. He was so unpretentious that many of his friends had no idea about his numerous accomplishments until his funeral service. Despite being so busy, one often saw him rolling up his sleeves to help, whether it was moving boxes to make space for a new trainee, or sitting down with a mentee with an excel spreadsheet to figure out what the latest data showed. Above all, he was an extraordinarily kind, generous man with a big heart. He was passionate about all aspects of his life, and lived it fully.

Larry is survived by Ilene, his wife of 46 years, son Josh, daughter Sarah, two grandchildren, and his brother. He will be missed enormously by his family, his friends, his colleagues, and his entire scientific field.