A single dose of cocaine can interfere with the ability to recognize negative emotions, according to new research presented at the annual European College of Neuropsychopharmacology (ECNP) conference in Amsterdam.
For their study, researchers from the Netherlands and Germany took 24 students between the ages of 19 and 27 with light to moderate cocaine use, and gave them either 300 mg of oral cocaine or a placebo.
After an hour or two, each student was then put through a series of biochemical tests, as well as a facial emotion recognition test to measure their responses to a series of basic emotions, such as fear, anger, disgust, sadness, and happiness.
The researchers found that, compared with a placebo, a single dose of cocaine caused an increased heart rate, as well as increased levels of the stress hormone cortisol. In addition, they found that the students who took cocaine found it more difficult to recognize negative emotions.
The researchers also found that students who showed a larger cortisol response after taking cocaine were even worse at recognizing negative emotions. When they were intoxicated with cocaine, their performance was 10 percent worse compared to their performance after taking a placebo, in recognizing sadness and anger, according to the researchers.
“This is the first study to look at the short-term effect of cocaine on emotions,” said lead researcher Dr. Kim Kuypers of the Maastricht University in The Netherlands.
“It shows that a single dose of cocaine interferes with a person’s ability to recognize negative emotions, such as anger and sadness. This might hinder the ability to interact in social situations, but it may also help explain why cocaine users report higher levels of sociability when intoxicated — simply because they can’t recognize the negative emotions.”
Commenting for the ECNP, Dr. Michael Bloomfield of University College, London, added that “there are many mental illnesses in which our brains’ ability to recognize the emotions of others are impaired. This new study shows that cocaine may interfere with this process too.
“Since cocaine changes the level of the brain chemical dopamine, this new study may have implications for other mental illnesses, such as depression and schizophrenia, where dopamine may also be involved in how we recognize emotions.”
“We know that cocaine is a powerful and addictive drug and an important question remains: Does cocaine mess up this process so that when cocaine users are off the drug they feel like other people have more negative emotions?”