This document discusses substance related disorders including definitions of terms like intoxication, withdrawal, tolerance, dependence, and abuse. It covers the phenomenology, clinical picture of intoxication, withdrawal, tolerance, physical and psychological dependence. It discusses major substances of abuse like alcohol, cannabis, opioids. It covers epidemiology, etiology including genetics. Impacts of substance use in college are discussed regarding academic performance, physical/psychological health, finances, and legal issues. Treatment options and approaches are outlined including managing intoxication/withdrawal, behavioral interventions, pharmacotherapy, treating co-occurring disorders and medical conditions.