Aug. 4, 2022 – Its effect is felt a few hours after the first dose, whereas traditional antidepressants take several weeks to act. Although its prescription is increasing for this type of treatment, this substance is still widely debated within the scientific community.

‘‘Some people believe that ketamine presents a strong addictive risk if taken for a long time, others do not. The whole point of our research was to try to provide some answers,’’ explains Christian Lüscher, a Full Professor in the Department of Basic Neurosciences at the UNIGE Faculty of Medicine and a specialist in the mechanisms underlying addiction.

Addiction vs. Dependence

Addiction is defined as the compulsive use of a substance despite its negative consequences (behavioural disorder). Dependence, on the other hand, is characterised by the appearance of one or more withdrawal symptoms on abrupt cessation of use (physiological disorder). Dependence – the physical manifestations of which vary greatly depending on the drug – affects everyone. Addiction, on the other hand, affects only a minority of people and is not caused by all drugs.

In the case of cocaine, for example, only 20% of users become addicted, even after prolonged exposure. For opiates, the rate is 30%. In its recent work, Christian Lüscher’s team sought to assess the risk of addiction to ketamine.

Short stimulation of the reward system

The UNIGE researchers used a device that allowed mice to self-administer doses of ketamine. ‘‘The drugs intensely stimulate the reward system in the brain, which leads to an increase in dopamine levels. The first step was to observe whether this mechanism was also at work when taking ketamine,’’ explains Yue Li, a Postdoctoral Scholar in the Department of Basic Neuroscience at the UNIGE Faculty of Medicine.


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