Single Dose Of Cocaine Linked To Greater Problems Recognizing Negative Emotions

Emotions
European researchers are finding cocaine can have a damaging effect on the way users perceive sadness and anger. Daniel CC BY-NC 2.0

The effects of cocaine are well documented, from the effect it has on our brain’s dopamine to the negative consequences of an overdose. But researchers from the Netherlands and Germany may have one more damaging effect to add to the list: the lessened ability to recognize negative emotions.

According to their study, which was presented during this year's 28th meeting of the European College of Neuropsychopharmacology (ENCP) in Amsterdam, a single dose of cocaine is enough to interfere with how we perceive emotion. The study involved 24 students who considered themselves "light to moderate cocaine users," from ages 19 to 27. Researchers gave each student either 300 milligrams of oral cocaine or a placebo; then, after a couple of hours, they gave participants a series of biochemical tests and a facial emotion recognition task. The task measured the participants' response to basic emotions, including fear, sadness, anger, disgust, and happiness.

Compared to the placebo, the team found that a single dose of cocaine increased both the level of the stress hormone cortisol in the brain and heart rate. Researchers also saw that the participants who took cocaine struggled more to recognize negative emotions than those who took the placebo. Namely, cocaine users who had a larger increase of cortisol after doing the drug had a less distinct impairment of recognizing negative emotions. This means when they were on cocaine, their ability to recognize sadness and anger was 10 percent worse compared to their performance while taking a placebo.

This is the first study to look at the short-term effects of cocaine on emotions, according to Dr. Kim Kuypers, lead researcher from the Maastricht University in The Netherlands. She stressed that a single dose was all it took to interfere with a person’s ability to recognize emotions.

“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,” she said.

Dr. Michael Bloomfield of the University College, London commented for the ECNP, saying that the findings could have potential value in studying mental illness.

“Since cocaine changes the level of the brain chemical dopamine, this new study may also have implications for other mental illnesses such as depression and schizophrenia — where dopamine may also be involved in how we recognize emotions,” he said.

Bloomfield also posed a question about cocaine users and the way they perceive the world when they aren't on the drug.

“We know 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?”

Source: Kuypers K, Steenbergen L, Theunissen E, Toennes S, Ramaekers J. Emotion recognition during cocaine intoxication. European College of Neuropsychopharmacology 28th Annual Meeting. 2015.

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