Substance Use and Abuse Across the Life Span

Substance Dependence

The hallmark of dependence is the continued use of a substance despite the experience of significant psychological and/or physiological symptoms related to intake (American Psychiatric Association, 1994). Prominent features include tolerance, the need to consume increasing amounts of the substance in order to maintain the desired level of intoxication, and withdrawal, the experience of unpleasant physiological symptoms that occurs when intake of the substance declines or ceases entirely. In addition, dependent individuals often experience a disruption in the performance of daily activities, a departure from social relatioships, and unsuccessful attempts to cut down or eliminate their substance use.

Substance Abuse

Substance abuse is characterized by a pervasive pattern of substance use that results in undesirable consequences for the user (American Psychiatric Association, 1994). These consequences often include legal problems, an inability to fulfill responsibilities, and interpersonal problems. Substance abuse is considered a lesser form of the disorder and can be distinguished from dependence by the absence of significant physical or physiological problems related to use.

Normal Experimentation

Alcohol and drug use among adolescents is a devastating problem in our society. However, it is important to distinguish between age-appropriate experimentation and problem use. Not all adolescents who experiment with alcohol or drugs will develop a crippling dependence. In one study of adolescent drug use and psychological health, 68% of a general sample had tried marijuana, 37% had tried cocaine, 25% had tried hallucinogens, and approximately 10% had tried amphetamines, barbiturates, tranquilizers, or inhalants (Shedler & Block, 1990). Although these statistics are disturbing, it is highly unlikely that all of these adolescents will experience problems with substance use later in life. In fact, Shedler and Block found a curvilinear relationship between the frequency of drug use and psychological health; that is, experimenters were psychologically healthier than both abstainers and frequent users. When compared with the experimenters, frequent users were “alienated, deficient in impulse control, and manifestly distressed” and abstainers were “anxious, emotionally constricted, and lacking in social skills” (Shedler & Block, 1990, p. 624). These results suggest that some degree of drug experimentation is a typical part of adolescent development and does not necessarily lead to problematic use.

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