We all know that smoking can cause many health problems, including cancer, lung disease, and heart conditions. But what isn't as well known is smoking's connection to depression. "But Smoking Makes Me Happy: The Link Between Nicotine and Depression" describes what scientists know about this connection. Many people with depression also smoke. Nicotine's effects on the brain are similar to the chemical imbalances many researchers believe can trigger depression. What's more, treating depression can help someone stop smoking. Ultimately, the best way to avoid the link between depression and smoking? A lifestyle built on exercise, good diet, and a healthy social support system.