Nehal P. Vadhan, Ph.D.

Dr. Nehal Vadhan is an Assistant Professor of Clinical Psychology in the Department of Psychiatry at the College of Physicians and Surgeons of Columbia University, and Director of Psychological Evaluation in the Substance Use Research Center at the New York State Psychiatric Institute. Dr. Vadhan received his PhD in 2003 from Hofstra University in Hempstead, NY, where he studied neuropsychological and social cognitive function in schizophrenia and comorbid substance abuse in the laboratory of Dr. Mark Serper. He completed his postdoctoral fellowship at Columbia University in substance abuse research in 2005, where he received training in human preclinical research under Dr. Richard Foltin, and in cognitive-behavioral treatment of substance use disorders under Dr. Kenneth Carpenter. Since coming to Columbia, Dr. Vadhan has focused on studying the acute and chronic neuropsychological effects and sequelae of cocaine and marijuana use, and he has received a Career Development Award (K01) from the National Institute on Drug Abuse to support this work. He also works as a clinician in the Division’s Substance Use Treatment and Research Service, and as a clinical neuropsychologist at Comprehensive Neuropsychological Services in NYC, specializing in evaluation of ADHD and Learning Disabilities.


Current Research Activities:

Neuropsychological sequelae of cocaine and marijuana use
The potential effects of drugs of abuse on cognitive functioning are of significant clinical and public concern. However, research findings in this area remain inconclusive. One reason for this may be the lack of convergence between two major paradigms used to assess the effects of drugs of abuse on neurobehavioral functioning: neuropsychology and behavior pharmacology. Thus, Dr. Vadhan and colleagues are developing a translational laboratory model that integrates these approaches. Research projects in this area include studies of the acute effects of marijuana and cocaine on executive function, studies of stimulus-response learning and reward sensitivity in cocaine-abusing individuals (ongoing collaboration with Drs. Mark Gluck and Catherine Myers, from Rutgers University), and studies of neuropsychological differences in long-term and short-term cocaine abusers.

Differences in substance-abusing individuals seeking and not seeking treatment
While substance abuse remains prevalent in American society, only a minority of abusers is seeking professional treatment for their abuse at any given time. Preliminary data suggest that treatment seekers and nontreatment seekers differ in substantial ways, including severity of substance dependence, subjective distress at substance use, and psychiatric comorbidity. Further exploration of differences between these subgroups may aid in understanding the treatment-seeking process for substance abuse. In particular, we have an interest in examining differences in neuropsychiatric function and verbal-cognitive characteristics between these groups, domains that have shown to be related to engagement and success in cognitive-behavioral treatment. Research projects comparing cocaine-dependent treatment seekers and nontreatment seekers include examinations of attentional bias towards cocaine-related stimuli and examination of expectancy of cocaine’s effects.

Other areas of research interest include the psychometric properties of neuropsychological tasks commonly used in substance abuse research, and the relationship between substance abuse and psychosis.

Recent Publications