This chapter outlines the major features of substance-related and addictive disorders, as well as other impulse-control disorders. This topic is of particular interest in a university setting, as this is typically the time most folks will first experience these concerns. Many of the drugs discussed in this chapter have effects similar to the symptoms of psychological disorders, such as mood swings and paranoia. What does this tell you about underlying biological or other factors in drug use? Why is marijuana the most frequently used illegal drug in society? Colorado and several other states have recently legalized marijuana. Now that we’ve had a few years to see this in action, how do you believe it’s worked out for Colorado? What are some pros and cons to this change in law? What are some of the unintended consequences we’ve seen played out? If you could vote on this again today after all that we now know, which way would you vote? How is pathological gambling similar to, and different from, substance use disorders? What have we learned from the treatment of substance-related disorders that may be applied to pathological gambling?