| There are various patterns of substance use and abuse, including a tendency among substance abusers to take a variety of drugs simultaneously or in a sequence to obtain specific effects. Patterns of use generally fall along a continuum ranging from experimental to compulsive use. Although an individual may move back and forth among patterns, compulsive use is indicative of addiction, and only abstinence or a drug-free status can break this pattern. Risk Factors Associated with Substance Abuse Although numerous studies have focused on the problem of substance abuse, the cause (or causes) remains unknown or unclear. Substance abuse is a multidimensional phenomenon with a multifactorial etiology. However a variety of factors can increase an individual's vulnerability or risk for developing problems of substance abuse. | 
