Chapter 12: substance-related disorders: the pathological use of substances falls into two categories: substance abuse and substance dependence. Substance dependence is characterized by dsm-iv-tr as the presence of at least three of the following: The person develops tolerance, indicated by either (1) larger doses of the substance being needed to produce the desire effect or (2) the effects of the drug becoming markedly less if the usual amount is taken. Withdrawal symptoms negative physical and psychological effects develop when the person stops taking the substance or reduce the amount. The person uses more the substance or uses it for a longer time than intended. The person recognizes excessive use of the substance; he or she may have tried to reduce usage but has been unable to do so. Much of the person"s time in spent in efforts to obtain the substance or recover from its effects. Substance use continues despite psychological or physical problems caused or exacerbated by the drug.