Chemical dependency entails a counterproductive pattern of of substance use which causes significant impairment or distress. The Diagnostic and Statistical Manual of Mental Disorders clarifies that to diagnose chemical dependence, additional signs must be present. The presence of these signs are strong indicators that someone is suffering from chemical dependency and may need treatment.
Tolerance
When tolerance to a substance develops, it means that drug use has become regular and significant enough that the user continually increases their dosage of the substance. In their book "Uppers, Downers, All-Arounders," Haight Ashbury Detox Clinic clinicians Darryl Inaba and William Cohen describe tolerance as the the phenomenon of drug users taking larger and larger amounts of the drug in order to achieve the same effect. Tolerance development signifies a substance use problem. Tolerance can lead to overdose and other medical problems due to the high dosages used.
Withdrawal
The second most significant sign of chemical dependency is withdrawal. When a drug user stops taking a drug to which they have developed a tolerance, the body's chemistry is altered. Inaba and Cohen define withdrawal is the body's attempt to rebalance itself after cessation of prolonged drug use. All of the functions the body was kept from doing while using the drugs, it now does to excess. For example, withdrawal from opiates such as heroin includes symptoms such as pain, anxiety, rapid pulse and muscle cramps. Withdrawal symptoms can keep addicts using drugs in order to avoid these effects.
Inability to Decrease Usage
Another hallmark of chemical dependency is the user's unsuccessful attempts to cut down on his usage. Addicts may deny that they have a problem, or may not want to quit. Whether or not this is the case, usually someone which chemical dependency has at least privately attempted to curtail his drug use, often after a negative experience related to drug use. When these attempts do not succeed, or succeed only very briefly, this is a strong indicator of chemical dependency.
References
- "Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision"; American Psychiatric Association; 2000
- "Uppers, Downers, All-Arounders"; Darryl Inaba and William Cohen; 2000


