PET Scan Helps Predict Success During Cocaine Treatment
Cocaine and Contingency Management
Contingency management-based programs offer incentives designed to encourage abstinence from substance use and adherence to other established treatment guidelines. Some programs use a voucher system, which provides a redeemable coupon every time a participant submits a urine sample that doesn’t contain drugs. Each coupon can be exchanged for things such as food or passes to favored activities, or for valuable services. Other programs used a prize-oriented system to encourage substance abstinence and treatment compliance. In such a system, every drug-free urine sample results in a chance to win a certain amount of cash in a scheduled drawing similar to a raffle. This means that the submission of multiple drug-free samples progressively increases the odds of winning the drawing. Conversely, submission of a sample that contains drugs reduces the chances of winning the drawing all the way back to zero.
Contingency management has proven usefulness in the treatment of various forms of stimulant addiction, including cocaine addiction. While a voucher-based or prized-based approach may bring positive results, voucher-based programs are particularly well noted for their usefulness for people addicted to cocaine.
PET scans are positron emission tomography scans. Like better known MRI scans and CT scans, these procedures give doctors a detailed view of the body’s interior. However, while MRI scans and CT scans focus on blood flow patterns and the structures of tissues and organs, PET scans focus on the actual function of tissues and organs. In addition to the brain, doctors can order these types of scans for parts of the body that include the lungs, heart and breasts. During a PET scan, a technician introduces a radioactive tracer material into the bloodstream, waits for this material to circulate, then uses a device similar to an MRI machine to gather in-depth images of the targeted body area.
Predicting the Success of Treatment
In the study slated for publication in Drug and Alcohol Dependence, the New York State Psychiatric Institute researchers used an examination of 24 people receiving treatment for cocaine addiction to help determine if it’s possible to predict who will benefit substantially from contingency management. All of these people underwent PET scans that assessed the function in five areas of the brain known to be affected by the process of addiction. In addition, the researchers gathered information that included the severity of each study participants’ addiction symptoms upon entry into treatment, the demonstrated level of response to contingency management in the first weeks of treatment and the demonstrated level of motivation during recovery.
The researchers concluded that activity in four out of the five areas measured by PET scans has little or no value in predicting how well a person will respond to contingency management. However, they also concluded that activity in the part of the brain that determines how people respond to rewards does help predict treatment success. When they looked at the other factors under consideration, the researchers concluded that initial severity of addiction has no predictable impact on treatment outcomes. However, they also concluded that an initial positive response to contingency management does predict success, as does a high level of personal motivation. On their own, PET scans and the treatment factors under consideration each help predict positive outcomes roughly 83 percent of the time. In combination, the approaches produce a maximum prediction rate of approximately 96 percent.
Based on their findings, the study’s authors concluded that the combination of PET scans, initial responses to contingency management and treatment motivation make it possible to accurately identify people who will do well in contingency management-based cocaine addiction programs. They emphasize the need for further research to determine how the observed changes in brain function influence the odds of treatment success.