Drug Addiction ‘Turned Off’ With Lasers

A groundbreaking study on rats from the National Institutes of Health may herald a revolutionary new treatment for cocaine addicts. By identifying a specific region of the brain that is diminished in rats susceptible to cocaine addiction, researchers were able to reduce their drug-seeking behavior by targeting the light from a laser onto the specific area. The effect is truly remarkable—by essentially reinvigorating the area in the brain, the drug-seeking behavior was notably reduced. If this is applied effectively to humans, it could provide a unique and effective approach to the treatment of numerous drug addictions.

Modeling Addiction in Rats

Research on rats might not seem like the best model for drug addiction in humans because of the obvious differences between us as species. However, it’s been found that the neural pathways in rats are nearly identical to those in humans, so rats are actually excellent models for addiction. Like humans, some rats display a tendency to become addicted to drugs while others don’t have the same problem. This is tested using a cocaine-dispensing lever, and it was found that some rats compulsively take cocaine while others weren’t particularly interested. The fact that the addicted rats continue to push the lever to get the drug even when it results in an electric shock to the foot further adds weight to the model. This research indicates that there is an underlying physiological reason that some humans become addicted and some do not.

Identifying the Region

The University of California researchers built on existing brain imaging research which identified that deficits in the pre-frontal cortex region were associated with drug addiction by looking at addicted rats. They compared the neuron firing patterns in addicted rats to those of non-addicted rats and confirmed that cocaine produces bigger defects in the addiction-prone animals. The precise targeting of the region enabled them to make specific alterations to see if it affected the animals’ behavior.

Treating the Condition

Making minute alterations to the functioning of specific areas in the brain is obviously challenging and potentially dangerous. By making genetic alterations and introducing light-sensitive compounds into the rats’ neurons, the researchers were able to make the biological equivalent of a switch. They did this in the brains of both the addicted and non-addicted rats so they were able to test the theory in two ways. Shining a laser light at the compound flicks the switch, activating or deactivating the specific region of the brain and therefore either creating or removing the defects seen in drug addicts.

The results confirmed the theory. When the “switch” was activated in the addicted rats—removing their inherent deficits—they didn’t press the lever as often for a dose of cocaine. Astoundingly, when the switch was deactivated in the non-addicted rats (mimicking the addicted brain) they actively used cocaine more. This is particularly important because it establishes a causal link between this defect and addictive behavior.

Applying it to Humans

Thanks to the similarity between human and rat brains, the research can be easily applied to humans, and clinical trials are already in the planning stages. However, lasers will probably not be used in the human version of the treatment, according to the researchers, with the preferred method being trans-cranial magnetic stimulation. This basically uses an electromagnet placed outside the scalp to achieve the same effect. The treatment is currently used for the treatment of depression, and could be easily adapted for the new purpose.

What Does It Mean for Treatment?

Cocaine addiction is one of the most challenging addictions to treat from a medical perspective, because there aren’t any FDA-approved medications which can be used for it. If this approach is shown to be successful in clinical trials, it could provide a valuable tool for rehabilitation centers all across the country. Medical treatments can’t fully address the multi-faceted issue of drug addiction, but by reducing cravings it allows counselors and other psychiatric professionals to deal with the underlying psychological issues that lead to addiction.

Although the initial research focused on cocaine addiction, the treatment could also be applied to other drugs. Different chemicals have different effects, but psychoactive drugs can be broadly classified as working through a similarity to natural compounds, often the “reward” chemical dopamine. This means that there is a great degree of similarity between different addictions (even when substances are not involved) and that making small modifications could allow the treatment approach to work with other drugs.

It is not a “magic bullet,” however. Drug addiction often results from things like poor methods of dealing with problems like stress or depression, and correcting the neurological differences doesn’t teach substance abusers better coping mechanisms. The non-invasive nature of the treatment is extremely promising, but it won’t “cure” the problem in the same way that drugs for opiate addictions haven’t stopped heroin abuse. However, the new research may provide a valuable component to a multi-faceted approach to treating drug addiction.