Could you explain the DSM-5's section on substance-related and addictive disorders in laymen's terms?

In the Diagnostic and Statistical Manual-5 (DSM-V), there have been several changes related to diagnosing substance use. There were previously two categories to diagnose substance use — substance abuse and substance dependence, as it was thought that substance abuse was the first phase people went through, followed by substance dependence. Research now suggests the substance abuse phase can be very severe, so these two separate categories have now been combined into one, called Substance Use Disorder. This diagnosis requires 2-3 symptoms from a list of 11, while the older diagnosis of substance abuse only required one symptom. With the exception of caffeine, each substance is classified as a separate disorder. 

In addition, Gambling Disorder has been added to the section called Addictive Disorders, as it is now recognized as similar to substance disorders with regard to its cognitive origins, clinical presentation, physiology, comorbidity, and treatment. Internet Gaming Disorder is still in Section III of the DSM-V, the section for disorders that require further research. Caffeine use disorder is not a diagnosis in the DSM-V, though there is research that discontinued use can result in withdrawal symptoms. It is also in Section III, marked for future research.