According to the National Institute on Drug Abuse (NIDA) drug addiction is classified as a mental illness because addiction changes the brain in fundamental ways, disturbing a person’s normal hierarchy of needs and desires, and substituting new priorities connected with procuring and using drugs. The resulting compulsive behaviors that override the ability to control impulses despite the consequences are similar to hallmarks of other mental illnesses.
In fact, the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the definitive resource of diagnostic criteria for all mental disorders, includes criteria for drug use disorders, distinguishing between two types: drug abuse and drug dependence. Drug dependence is synonymous with addiction. By comparison, the criteria for drug abuse hinges on the harmful consequences of repeated use but does not include the compulsive use, tolerance (i.e., needing higher doses to achieve the same effect), or withdrawal (i.e., symptoms that occur when use is stopped) that can be signs of addiction.
Many people who regularly abuse drugs are also diagnosed with mental disorders and vice versa. The high prevalence of this comorbidity has been documented in multiple national population surveys since the 1980s. Data show that persons diagnosed with mood or anxiety disorders are about twice as likely to suffer also from a substance use disorder (abuse or dependence) compared with respondents in general. The same is true for those diagnosed with an antisocial syndrome, such as antisocial personality or conduct disorder. Similarly, persons diagnosed with substance use disorders are roughly twice as likely to suffer also from mood and anxiety disorders.
Adolescence–A Vulnerable Time. Although substance abuse and addiction can happen at any time during a person’s life, drug use typically starts in adolescence, a period when the first signs of mental illness commonly appear. It is therefore not surprising that comorbid disorders can already be seen among youth. Significant changes in the brain occur during adolescence, which may enhance vulnerability to drug use and the development of addiction and other mental disorders. Drugs of abuse affect brain circuits involved in learning and memory, reward, decision making, and behavioral control, all of which are still maturing into early adulthood.
One of the brain areas still maturing during adolescence is the prefrontal cortex– the part of the brain that enables us to assess situations, make sound decisions, and keep our emotions and desires under control. The fact that this critical part of an adolescent’s brain is still a work in progress puts them at increased risk for poor decision making (such as trying drugs or continuing abuse). Thus, introducing drugs while the brain is still developing may have profound and long-lasting consequences.
The more we learn, the better we understand the abilities and vulnerabilities of teens, and the significance of this stage for life-long mental health. The fact that so much change is taking place beneath the surface may be something for parents to keep in mind during the ups and downs of adolescence.
Drug abuse and addiction have negative consequences for individuals and for society. Estimates of the total overall costs of substance abuse in the United States, including productivity and health- and crime-related costs exceed $600 billion annually. This includes approximately $193 billion for illicit drugs, $193 billion for tobacco, and $235 billion for alcohol. As staggering as these numbers are, they do not fully describe the breadth of destructive public health and safety implications of drug abuse and addiction, such as family disintegration, loss of employment, failure in school, domestic violence, and child abuse.
Many people do not understand why or how other people become addicted to drugs. It is often mistakenly assumed that drug abusers lack moral principles or willpower and that they can stop using drugs simply by choosing to change their behavior. In reality, drug addiction is a complex disease, and quitting takes more than good intentions or a strong will. In fact, because drugs change the brain in ways that foster compulsive drug abuse, quitting is difficult, even for those who are ready to do so. Through scientific advances, we know more than ever before about how drugs work in the brain, and we also know that drug addiction can be successfully treated to help people stop abusing drugs and lead productive lives.
Treatment is available to help people counter addiction’s powerful disruptive effects. Similar to other chronic, relapsing diseases, such as diabetes, asthma, or heart disease, drug addiction can be managed successfully. Drug addiction is a preventable disease. Research has shown that prevention programs involving families, schools, communities, and the media are effective in reducing drug abuse.