Summary: A new article investigates the link between addiction and mental health disorders.
Source: Neuroscience News.
Reports published in the Journal of the American Medical Association tell us that about 50 percent of people with severe mental disorders are affected by substance abuse and roughly 37 percent of alcohol abusers, and 53 percent of drug abusers, also have at least one serious mental illness.
This dual diagnosis is a problem that clearly goes both ways. But science has a long way to go before we can truly understand why a dual diagnosis of mental illness and addiction is so common.
People with major psychiatric disorders, including schizophrenia, bipolar and unipolar depression, post-traumatic stress disorder, borderline and antisocial personality disorders are much more likely to have a Substance Use Disorder (SUD) than the general population.
Alone, this information suggests that psychiatric disorders may predispose you to developing a substance use disorder. But is truly the case?
Another popular theory is that people with mental illnesses are self-medicating when they abuse substances.
Theory of self-medication
There are obvious reasons why someone with a mental health disorder may choose to self-medicate. Many street drugs work in a way that’s similar to, or the same way as the prescription drugs that are used to treat various disorders. For people who have limited access to healthcare, street drugs are much easier to get.
Here are some examples of how street drugs may initially seem to treat symptoms of a mental health disorder.
Methamphetamines – The structure of the methamphetamine molecule is similar to the structure of amphetamine and dopamine. In small doses, methamphetamines block dopamine re-uptake. In larger doses, this drug increases dopamine release. Methamphetamines are powerful stimulants, and users will feel a high from the dopamine surge.
Cocaine – Cocaine works by binding to the dopamine transporter and blocking the removal of dopamine. Naturally, as dopamine builds up in the synapse, it triggers a signal to the receiving neurons. This is what triggers the euphoric feeling. It’s that feeling that may make people think they are treating symptoms of ADD or ADHD.
Adderall and Ritalin – Both of these prescription drugs are central nervous system stimulants. They increase norepinephrine and dopamine in your CNS connections, which quickens brain activity. Although these are prescription drugs, they are often sold on the street and abused by people who are self-medicating.
Alcohol – Alcohol is a depressant that tricks the brain into thinking that it’s having a good time. It increases GABA to cause sluggish movement and slowed speech and suppresses glutamate, which causes a physiological slowdown. Although these aren’t typically desired outcomes, people self-medicate with alcohol because it increases dopamine in the brain’s reward center. People may self-medicate with alcohol to treat depression or social anxiety, but depression inevitably worsens over time.
Benzodiazepines – These drugs enhance GABA at the GABAA receptor, and this causes a sedated effect. Someone who is self-medicating may use benzos to treat anxiety or insomnia.
Another theory on dual diagnosis
Although the self-medication theory is logical, there may be more to the story.
A December 2017 study published in Behavioral Neuroscience suggests that this dual diagnosis may stem from developmental changes to the amygdala.
Chambers and other researchers from the Indiana University medical school compared the mood- and drug-related behavior of two groups of adult rats.
The first group featured rats whose amygdalas were surgically damaged as infants. The second group contained rats who underwent a fake surgery as infants, but their amygdalas were left intact.
Researchers found that rats with damaged amygdalas weren’t as responsive to ambiguous or threatening stimuli. You might consider this group more laid-back. These rats didn’t get as stressed in a maze and they didn’t show signs of concern when a predator was within smelling distance. They were also more motivated by novelty than the second group.
When researchers gave the rats cocaine, the rats with damaged amygdalas were more sensitive to the drug’s effects. As they were given more cocaine injection, these rates continued to express stronger sensitivity and behavioral changes. This suggests that they were more sensitive to the addictive process than the rats who did not have damaged amygdalas.
Since the only difference in the two groups was the condition of their amygdala, we can assume that the damage caused a predisposition to addition.
What causes amygdala damage?
The Behavioral Neuroscience study results are interesting, but they leave a few questions unanswered:
- Could people with a dual diagnosis of addiction and mental illness have damaged amygdalas?
- What could harm the amygdala in infancy?
Dr. Chambers speculates that “early emotional trauma, paired with a certain genetic background, may alter the early development of neural networks intrinsic to the amygdala, resulting in a cascade of brain effects and functional changes that present in adulthood as a dual-diagnosis disorder.” Temporal lobe epilepsy, brain injury or tumors may also cause amygdala damage, but these are relatively rare.
Drug abuse may lead to mental illness
Different drugs impact the body in different ways, and some may even lead to depression or more severe forms of mental illness, according to a recent Biological Psychiatry: Cognitive Neuroscience study. The study suggests that long-term marijuana use can have potential negative long-term effects that include negative emotionality and a higher risk of psychosis.
Subjects who abused cannabis showed a marked increase in local functional connectivity density relative to control subjects. This was true for the ventral striatum and midbrain but also in the brainstem and lateral thalamus. These results were most pronounced for people who began using cannabis early in life.
Although we have a lot more to learn about a dual diagnosis of addiction and mental illness, recent studies shed light on how the brain may function similarly in both disorders.
About the Author: Trevor is a freelance writer and recovering addict & alcoholic who’s been clean and sober for over 5 years. Since his recovery began, he has enjoyed using his talent for words to help spread treatment resources, addiction awareness, and general health knowledge. In his free time, you can find him working with recovering addicts or outside enjoying about any type of fitness activity imaginable.
Source: Trevor McDonald – Neuroscience News
Publisher: Organized by NeuroscienceNews.com.
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