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Why Does the Brain React When Its Chemistry Changes? The Neuroscience of Withdrawal · Understanding the Brain

• 0:01
  Speaker 1: Today we look at brain zaps. Why stopping? Certain types
• 0:05
  Speaker 1: of medications like Cymbalta or Effexor can feel like electric
• 0:09
  Speaker 1: shocks in your head. If a person is taking Cymbalta
• 0:12
  Speaker 1: and forgets their medication one morning, by the following day
• 0:15
  Speaker 1: something unusual begins to happen. Every time they turn their
• 0:18
  Speaker 1: head or move their eyes, they experience a brief sensation
• 0:20
  Speaker 1: resembling an electrical shock inside their skull. Some describe it
• 0:25
  Speaker 1: as a sudden jolt. Others compare it to a buzzing sensation.
• 0:28
  Speaker 1: or a momentary electrical pulse. These sensations have become widely
• 0:32
  Speaker 1: known as brain zaps. But what is happening? To understand
• 0:35
  Speaker 1: the phenomenon, we need to examine how antidepressants influence communication
• 0:39
  Speaker 1: between nerve cells. Cymbalta, known generically as duloxetine, belongs to
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  Speaker 1: a class of medications called SNRIs, serotonin and norepinephrine reuptake inhibitors.
• 0:50
  Speaker 1: Neurons communicate by releasing chemical messengers called neurotransmitters. The two
• 0:55
  Speaker 1: important ones here are serotonin and norepinephrine, which are mood regulations. Normally,
• 0:59
  Speaker 1: after these chemicals are released into the space between the neurons,
• 1:02
  Speaker 1: you probably remember the synaptic cleft, specialized transport proteins help
• 1:06
  Speaker 1: remove them through a process called reuptake. They either take
• 1:09
  Speaker 1: them back in or they diffuse them later. However, Cymbalta
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  Speaker 1: inhibits these transporters, these taxicabs per se, increasing the availability
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  Speaker 1: of serotonin and norepinephrine. However, the brain is not a
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  Speaker 1: passive recipient of medication. Over weeks and months, neural systems
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  Speaker 1: adapt to changes in neurotransmitter signaling. Receptor sensitivity, intracellular signaling pathways,
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  Speaker 1: and other regulatory processes may adjust as the nervous system
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  Speaker 1: attempts to maintain stability. So what happens when someone abruptly
• 1:38
  Speaker 1: stops taking the medication? Cymbalta has an elimination half-life of
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  Speaker 1: about 12 hours. This means that, on average, the amount
• 1:46
  Speaker 1: of medication in the bloodstream declines by roughly half every
• 1:49
  Speaker 1: 12 hours after absorption and distribution are accounted for. After
• 1:53
  Speaker 1: 24 hours, approximately one-quarter of the original amount may remain.
• 1:58
  Speaker 1: After 48, just about 6%. These are simplified estimates, and
• 2:03
  Speaker 1: individual metabolism varies. But the important part is that medication
• 2:06
  Speaker 1: exposure can decline much faster than the nervous system reverses
• 2:09
  Speaker 1: its adaptations. The mismatch is believed to contribute to what
• 2:13
  Speaker 1: they call antidepressant discontinuation syndrome. On a side note, Prozac
• 2:18
  Speaker 1: has one of the longer half-lives of most of the
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  Speaker 1: antidepressants and also has active metabolites, which keeps it still
• 2:24
  Speaker 1: active for at least another two weeks or so. Let's
• 2:28
  Speaker 1: go back. Symptoms of discontinuation syndrome may include dizziness, nausea,
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  Speaker 1: sleep disturbances, flu-like sensations, and the brain zaps. But why
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  Speaker 1: the brain zaps? Well, scientists still don't know the precise
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  Speaker 1: mechanism of this. A hypothesis involves temporary changes in sensory
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  Speaker 1: processing as sebidrenergic and noradrenergic signaling readjusts. Another possibility involves
• 2:51
  Speaker 1: the vestibular system, which helps coordinate balance and head movement.
• 2:55
  Speaker 1: This is interesting because some people report that moving their
• 2:58
  Speaker 1: eyes from side to side triggers the sensation. Researchers have
• 3:01
  Speaker 1: suggested that changes in communication among sensory, vestibular, and brain
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  Speaker 1: step networks might contribute. Brain zaps are not known to
• 3:09
  Speaker 1: represent actual electrical shocks or seizures. Their electrical quality describes
• 3:12
  Speaker 1: the person's subjective experience rather than electrical discharge. That's important.
• 3:17
  Speaker 1: Not all of this antidepressants also produce the same discontinuations
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  Speaker 1: I mentioned. Prozac has a long-lasting effect. It has a
• 3:24
  Speaker 1: long half-life and a long-lasting active metabolite called neurofluoxetine. By contrast,
• 3:32
  Speaker 1: duloxetine or Cymbalta, Effexor, and Paxil generally have higher discontinuation risks.
• 3:38
  Speaker 1: For most people, discontinuation symptoms are temporary, although some experience
• 3:42
  Speaker 1: prolonged or particularly distressing symptoms. The lesson here is that
• 3:46
  Speaker 1: brain zaps reveal something fundamental about neuroscience. The brain is
• 3:49
  Speaker 1: constantly adapting to its chemical environment. When that environment changes suddenly,
• 3:54
  Speaker 1: neural systems may require to recreate equilibrium.