is usually, but not always, as sociated with a substance use disorder. Most individuals with
withdrawal have an urge to re-administe r the substance to reduce the symptoms. 
Route of Administration and Speed of Substance Effects
Routes of administration that produce more rapid and efficient absorption into the blood-
stream (e.g., intravenous, smoking, intranasal “snorting”) te nd to result in a more intense
intoxication and an increased likelihood of an escalating pattern of substance use leading
to withdrawal. Similarly, rapi dly acting substances are more likely than slower-acting
substances to produce immediate intoxication. 
Duration of Effects
Within the same drug category, relatively sh ort-acting substances tend to have a higher
potential for the development of withdrawal th an do those with a longer duration of ac-
tion. However, longer-acting substances tend to have longer withdrawal duration. The
half-life of the substance parallels aspects of wi thdrawal: the longer the duration of action,
the longer the time between cessation and th e onset of withdrawal symptoms and the lon-
ger the withdrawal duration. In general, the longer the acute withdrawal period, the less
intense the syndrome tends to be.
Use of Multiple Substances
Substance intoxication and withdrawal often involve several substances used simultane-
ously or sequentially. In these cases, each diagnosis should be recorded separately.
Associated Laboratory Findings
Laboratory analyses of blood and urine samples can help determine recent use and the specific
substances involved. However, a positive laboratory test result do es not by itself indicate that
the individual has a pattern of substance use that  meets criteria for a substance-induced or sub-
stance use disorder, and a negative test result does not by  itself rule out a diagnosis.
Laboratory tests can be useful in identify ing withdrawal. If the individual presents