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New experimental drugs will be able to relieve symptoms of depression within 24 hours with minimal side effects, which is especially important for patients at risk of suicide.
Most depressed patients today are prescribed drugs that increase levels of the neurotransmitter serotonin. The most popular class of these drugs is called selective serotonin reuptake inhibitors (SSRIs), and these include drugs such as Prozac, Cipralex, Paxil, Zoloft… According to the data, they help only a third of patients, and even then they begin to act only after 3-8 weeks of regular use. As a result, a person’s well-being does not improve for months, and in case of a risk of suicide, such a delay can be fatal.
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- Depression: pills or psychotherapy?
Researchers from the Medical School of the University of Maryland (USA), led by Scott Thompson, tried to influence another neurotransmitter – gamma-aminobutyric acid (GABA), which plays a critical role in inhibition processes. The work of the brain depends on the balance of excitatory and inhibitory signals exchanged between neurons. The researchers suggest that in patients with depression, excitatory signals in some areas of the brain are not strong enough. Science does not yet know a safe way to directly amplify excitatory signals, so researchers have studied substances that attenuate inhibitory signals transmitted by GABA. These substances have few unwanted side effects because they selectively affect only areas of the brain associated with mood.
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- Antidepressants and the will to live
The scientists tested the drug on rats. First, they subjected them to mild stress, which caused them to behave like depression in humans. When rodents were injected with substances of the NAM-GABA class, they lost the symptoms of the main symptom of depression – anhedonia, that is, the inability to experience pleasure. It is noteworthy that the effect appeared within 24 hours, and not many weeks, as is the case with conventional antidepressants.
By studying the brains of experimental rats, the researchers found that these substances very quickly indirectly increased excitatory signals in stress-reduced areas of the brain – the same ones that are thought to be associated with depression in humans. At the same time, these drugs did not have any effect on animals that were not subjected to stress, which allows us to hope that they will not cause side effects in humans.
Подробнее см. J. Fischell et al. «Rapid antidepressant action and restoration of excitatory synaptic strength after chronic stress by negative modulators of Alpha5-containing GABAA receptors», Neuropsychopharmacology, April 2015.