The University of Maryland School of Pharmacy will be using a $3.7 million grant to…
Cocaine Addiction Linked to Genetic Risks for Depression
Depression is the accepted term for a range of conditions, known technically as depressive disorders, that center on the presence of disruptive, “down” emotional states. There is considerable evidence that at least some of the risk for depression stems from genetic variations that affect the body’s use of a key chemical called serotonin. In a study published in April 2014 in the journal Drug and Alcohol Dependence, researchers from three U.S. institutions conducted testing designed to determine if people affected by cocaine addiction have an unusual susceptibility to genetically based, serotonin-related depression.
Depression and Serotonin
Most people are aware of the existence of major depression, a potentially debilitating depressive disorder that produces severe symptoms and impacts the health of a substantial minority of the U.S. population. The American Psychiatric Association also recognizes and officially defines a number of other depressive disorders, including persistent depressive disorder and disruptive mood dysregulation disorder. Depressive illnesses probably stem from a number of overlapping factors, the National Institute of Mental Health reports. In addition to genetic susceptibility, these factors include a range of influences from a person’s day-to-day environment, specific details of body function or biology, and details of a person’s psyche and personality.
Serotonin is produced inside the human brain and accumulates inside the brain, the bloodstream and the body’s intestinal tract. Among other things, this chemical acts as a neurotransmitter by enabling communication between nerve cells located in the brain and spinal cord (central nervous system). In its role as a neurotransmitter, serotonin helps control a number of critical mental and physical processes, including the maintenance of a stable mood, the body’s natural sleep/wake cycle and the brain’s ability to take in new information and form memories.
People affected by cocaine addiction have used the drug long enough and often enough to undergo lasting changes in a part of the brain popularly referred to as the pleasure center. These changes produce physical dependence by making the brain reliant on further cocaine intake in order to maintain its now-accustomed chemical surroundings. Additional symptoms of addiction to this stimulant drug commonly include recurring urges to use more cocaine, a related loss of ability to control cocaine consumption, decreasing sensitivity to the drug effects of any given amount of cocaine (i.e., rising tolerance) and withdrawal associated with a sharp decline or cessation of cocaine intake. Cocaine addiction and non-addicted cocaine abuse are both classified by the American Psychiatric Association as forms of stimulant use disorder, a condition that also encompasses diagnosable problems related to the intake of other stimulants drugs.
Increased Depression Risks
In the study published in Drug and Alcohol Dependence, researchers from the Icahn School of Medicine, Brookhaven National Laboratory and Stony Brook University used detailed testing to analyze the genetic variations in serotonin production that can potentially make a person more likely to develop diagnosable symptoms of depression. These researchers also sought to determine if people affected by cocaine addiction are unusually affected by these genetic variations. All told, 119 people took part in the study; 62 of these individuals were involved in dysfunctional cocaine use, while the remaining 57 did not use the drug. The researchers used a series of intentionally unpleasant images to test the emotional responses of all 119 participants. They also used a standard tool for depression screening called the Beck Depression Inventory to identify depression symptoms in each group of participants.
After reviewing their data, the researchers concluded that, independent of any involvement in cocaine use, study participants affected by at least two particular serotonin-related genetic variations had unusually strong responses to the unpleasant images. In addition, they concluded that the dysfunctional cocaine users with these genetic variations and strong responses typically had a higher number of depression symptoms than their counterparts who didn’t use the drug. This tendency toward increased depression was not found in any other study participants.
The study’s authors believe their findings indicate that the serotonin-related genetic risks for depression come from multiple sources inside the brain. More crucially for people dealing with cocaine addiction, they believe that their findings set the stage for further investigations into the problems that can appear in cocaine addicts or individuals affected by other forms of drug addiction. The authors also believe that their results may eventually help other researchers develop treatments that address addiction-related depression, as well as mood disturbances not related to the use of drugs or alcohol.