554 Substance-Related and Addictive Disorders
more prominent, and the individual may seek out multiple physicians to obtain sufficient
supplies of the medication. Tolerance can reach high levels, and withdrawal (including
seizures and withdrawal  delirium) may occur. 
As with many substance use disorders, sedati ve, hypnotic, or anxiol ytic use disorder gen-
erally has an onset during adolescence or early adult life. There is an increased risk for misuse
and problems from many psychoactive substances  as individuals age. In particular, cognitive
impairment increases as a side effect with ag e, and the metabolism of sedatives, hypnotics, or
anxiolytics decreases with age among older indi viduals. Both acute and chronic toxic effects
of these substances, especially effects on co gnition, memory, and motor coordination, are
likely to increase with age as a consequence of pharmacodynamic and pharmacokinetic age-
related changes. Individuals with major neuroc ognitive disorder (dementia) are more likely
to develop intoxication and impaired phy siological functioning at lower doses.
Deliberate intoxication to achieve a “high” is  most likely to be observed in teenagers
and individuals in their 20s. Problems associate d with sedatives, hypnotics, or anxiolytics
are also seen in individuals in their 40s and older who escalate the dose of prescribed med-
ications. In older individuals, intoxicati on can resemble a progressive dementia.
Risk and Prognostic Factors 
Temperamental. Impulsivity and novelty seeking are in dividual temperaments that re-
late to the propensity to develop a substanc e use disorder but may themselves be geneti-
cally determined. 
Environmental. Since sedatives, hypnotics, or anxiolytics are all pharmaceuticals, a key