• A substance use disorder can be conceptualized as a progression from an impulsive to a compulsive disorder

• This progression is linked to alterations not only in dopamine and the reward circuit, but also in other neurotransmitters and circuits involved in memory, motivation, executive function, and stress

• Of particular importance is the opioid system, which mediates the hedonic evaluation of natural rewards and also seems to play a role in drug reinforcement for numerous substances

• The management of SUDs can differ by substance, but it generally involves both psychosocial and pharmacological treatment

• The substances with evidence-based pharmacological treatments are alcohol, nicotine, and opioids

• Although there is some evidence in support of the concept of behavioral addiction, controversy remains as to whether the evidence is strong enough to warrant categorizing certain behaviors as addictions

• Currently, only pathological gambling is being recategorized as an addictive disorder