Withdrawal Symptoms of SSRI Discontinuation Syndrome

Selective serotonin reuptake inhibitors (SSRIs) are a class of drug commonly used to treat depression. The drugs help normalize brain function in persons with certain mood disorders by increasing the amount of serotonin in the brain. Serotonin is a type of chemical, called a neurotransmitter, whose purpose it is to deliver messages to and from the brain cells. By doing so, the chemistry in the brain can be regulated in a way that typically improves the person's depression or anxiety.

However, when SSRI treatment is stopped, some people may experience a form of withdrawal called SSRI discontinuation syndrome. It is most commonly seen when treatment is stopped abruptly and can manifest with symptoms that seem very much like the depression and anxiety. Because of this, people with often believe that they are having a "relapse" and request to be placed back on SSRIs.

The SSRI drugs used to treat mood disorders have similar mechanisms of action but varying degrees of drug half-life. Drug half-life is a term to describe how a long an active drug molecule stays in the bloodstream before being expelled from the body.

If a drug has a short half-life, it will require frequent dosing to maintain the ideal concentration in the blood. If it has a long half-life, it will remain in a steady state for longer and be less prone to ups and down.

SSRI medication used to treat depression include:

• Prozac (fluoxetine)
• Zoloft (sertraline)
• Paxil (paroxetine)
• Celexa (citalopram)
• Lexapro (escitalopram)

Of these, Prozac has a very long half-life and, when stopped, will gradually clear from the bloodstream. The others, by contrast, have a short half-life and, when stopped, will drop off abruptly. When this happens, the person may experience disconcerting and even profound symptoms of withdrawal.

But drug half-life is only part of the reason for these symptoms. When used over a period of time, SSRIs can effect changes in the brain that result in fewer and fewer serotonin receptors. This is due, in part, to the fact that SSRIs cause a surge of serotonin in the brain.

When this happens, the brain will "down-regulate" the number of receptors in response to the increased volume of serotonin. It's a physiological balancing act meant to prevent overstimulation of brain cells.

When treatment is eventually stopped, there will be fewer receptors than before and a short-term deficiency of serotonin activity. The body will typically correct this, but, until it does, a person may have to go through a period of adjustment until the system once again normalize.

The most common symptoms of SSRI discontinuation syndrome are described as either being flu-like or feeling like a sudden return of anxiety or depression. They include:

• Dizziness
• Vertigo
• Lightheadedness
• Difficulty walking
• Nausea/vomiting
• Fatigue
• Irritability
• Headaches
• Insomnia
• Diarrhea
• Muscle pain
• Chills
• Shock-like sensations
• Paresthesia (burning, prickly, or skin crawling sensations)
• Visual disturbances
• Impaired concentration
• Vivid dreams
• Depersonalization (a detached, out-of-body experience)
• Suicidal thoughts
• Psychosis
• Catatonia (a state of unresponsiveness)

When the symptoms can be uncomfortable, they are rarely severe. Most only experience mild to moderate forms of discontinuation syndrome.

All told, around 20 percent of people on Paxil, Zoloft, Celexa, or Lexapro will experience some degree of withdrawal following termination of treatment. Most last anywhere from one to seven weeks. For those who have been on SSRIs for many years, the symptoms may persist for longer.

To avoid the risk of SSRI discontinuation syndrome, speak with your doctor of about weaning you off the drug gradually. Typically speaking, if treatment has lasted less than eight weeks, tapering off over one to two weeks would seem reasonable. After six to eight months of treatment, you may need to taper off over the course six to eight weeks.

But take our advice: don't try to make this up on your own. Work alongside your doctor, who will better understand the limitations and potential hazards of any drugs you are taking.