Cocaine may impair ability to recognize negative emotions

A single dose of cocaine may impair an individual’s ability to recognize negative emotions such as sadness and anger, according to data presented at the 25th Annual European College of Neuropsychopharmacology Congress.

“This is the first study to look at the short-term effect of cocaine on emotions. It shows that a single dose of cocaine interferes with a person's ability to recognize negative emotions, such as anger and sadness,” researcher Kim Kuypers PhD, of Maastricht University, the Netherlands, said in a press release. “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.”

In the placebo-controlled, within-subject study, researchers evaluated 24 healthy light-to-moderate cocaine users aged 19 to 27 years. The researchers tested the participants 1 to 2 hours after taking 300 mg oral cocaine or placebo. The participants were evaluated on their ability to recognize low- and high-intensity expressions of basic emotions such as fear, anger, disgust, sadness and happiness. The researchers also measured the participants’ serum cortisol levels 1 hour post-treatment, and took heart rate and blood pressure three times on each test day (at baseline, before tests, and after tests).

They found that the single cocaine dose resulted in an increase in heart rate and cortisol levels, and an impaired ability to recognize negative emotions vs. placebo. Emotion recognition was influenced by the intensity of the depicted emotions; when high-intensity versions of anger and disgust were portrayed, those in the cocaine group demonstrated “normalized” or placebo-like levels of recognition, while the identification of intense sadness became more difficult. The normalized performances were most pronounced among participants in the cocaine group with the greatest cortisol responses compared with placebo.

According to Michael Bloomfield, MD, of University College, London, these findings may add insight into how recognition of emotion may be impaired in mental illnesses where dopamine is affected.

“There are many mental illnesses in which our brains' ability to recognize the emotions of others are impaired and this new study shows that cocaine may interfere with this process too,” Bloomfield said in a press release, on behalf of the European College of Neuropsychopharmacology. “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?”

Disclosure: The researchers report no relevant disclosures.

Reference:

Kuypers K, et al. Emotion recognition during cocaine intoxication. Presented at: European College of Neuropsychopharmacology Congress; Aug. 29-Sept. 1, 2015; Amsterdam.