Clinicians often use the terms use, misuse, abuse, and dependence when assessing an individual’s drug status. Of these, only the latter two terms are diagnostic categories in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), a comprehensive classification of officially recognized psychiatric disorders. 
“Use” is often applied to drug consumption that is not clinically significant.
“Misuse” is often applied to drug consumption that is clinically significant but does not meet diagnostic criteria for abuse or dependence. Again, the term misuse is not a formal diagnostic category.