Acute Withdrawal

What is Acute Withdrawal?

Acute withdrawal is the initial phase of withdrawal that can occur when a psychiatric medication to which the body has adapted is reduced, stopped, or sometimes when doses are missed.¹ Withdrawal symptoms can affect both the body and mind and can range from relatively mild and short-lived to severe and disabling. The experience varies considerably between individuals and between different medications.¹

For many medications, symptoms emerge relatively soon after a significant dose reduction or cessation. With antidepressants, withdrawal commonly begins within days, although medications with longer half-lives can produce a delayed onset.² Benzodiazepine withdrawal timing similarly varies according to factors including the drug's elimination rate and the manner in which it is withdrawn.³

Importantly, acute does not mean insignificant. While some people experience relatively mild symptoms that resolve without intervention, others can experience severe withdrawal requiring careful clinical management.¹

Why Does Acute Withdrawal Happen?

With continued exposure to certain psychiatric medications, the nervous system adapts to their presence. This physiological adaptation is known as physical dependence and can occur even when a medication is taken exactly as prescribed.¹

When the medication is suddenly removed or its dose is reduced faster than the nervous system can accommodate, this adapted system is forced to function with substantially less of the drug. Withdrawal symptoms can then emerge while the body adjusts to the pharmacological change.¹

This is one reason why physical dependence should not be confused with addiction. A person does not need to crave, misuse or compulsively seek a medication to experience withdrawal from it. NICE explicitly distinguishes dependence from addiction and recognises antidepressants, benzodiazepines, Z-drugs, gabapentinoids and opioids as medicines associated with withdrawal symptoms.¹

What Does Acute Withdrawal Feel Like?

Withdrawal is not purely psychological. Depending on the medication involved, acute withdrawal can produce a combination of neurological, physical, emotional, cognitive and autonomic symptoms.¹˒²

These may include:

• dizziness, vertigo or problems with balance

• nausea or gastrointestinal disturbance

• sweating and palpitations

• tremor

• headaches and flu-like symptoms

• insomnia or disturbed/vivid dreams

• sensory disturbances, including electric-shock sensations or “brain zaps”

• agitation and irritability

• anxiety or sudden surges of panic

• rapidly changing mood

• difficulty concentrating

• derealisation

• profound restlessness or akathisia

• other symptoms specific to the medication being withdrawn.¹˒²˒⁴

The Royal College of Psychiatrists notes that antidepressant withdrawal can involve symptoms that a patient has never experienced as part of their original psychiatric condition, including electric-shock sensations and unfamiliar physical or psychological experiences.⁴

Acute Withdrawal Can Be Mistaken for Relapse

One of the most important problems surrounding acute withdrawal is that many symptoms overlap with anxiety, depression and other psychiatric conditions.

A patient who suddenly develops anxiety, insomnia, low mood or agitation following a medication reduction may therefore be told that their original illness has returned, when withdrawal should also be considered.⁵

There are several clues that can help distinguish the two.

Withdrawal often begins soon after a dose reduction or cessation, whereas relapse commonly develops over a longer period. (However, this is not an absolute rule. Many members of the withdrawal community report a "honeymoon period" after cessation or reduction, only to be hit with a delayed withdrawal wave later. This makes withdrawal and relapse difficult for many healthcare providers to distinguish). Withdrawal may also produce new, distinctive neurological and physical symptoms - such as dizziness, nausea and electric-shock sensations - alongside psychological symptoms.⁵

Horowitz and Taylor argue that the combination of timing, unfamiliar symptoms, physical symptoms and the characteristic pattern following dose reduction can help clinicians distinguish antidepressant withdrawal from relapse.⁵

See also: Withdrawal vs Relapse

How Long Does Acute Withdrawal Last?

There is no universal timeline. With antidepressants, symptoms following a relatively modest reduction may begin within days, intensify and then diminish over subsequent days or weeks. However, there is substantial variation, and larger reductions can produce symptoms that persist considerably longer.⁵

NICE specifically warns clinicians that withdrawal symptoms:

• can appear within days of reducing or stopping a medication;

• may sometimes have a delayed onset;

• can vary substantially in severity;

• and may persist considerably longer than patients or clinicians expect.¹

The Royal College of Psychiatrists similarly recognises that while some people experience mild symptoms that disappear relatively quickly, others experience considerably more severe and longer-lasting withdrawal.⁴

This is why statements such as “withdrawal only lasts a week or two” should not be treated as a universal rule.

When Acute Withdrawal Becomes Protracted

For many patients, withdrawal symptoms gradually settle as the nervous system adapts. For others, symptoms continue beyond the expected acute period and may persist or fluctuate for much longer. This is generally described as protracted withdrawal or prolonged withdrawal syndrome.⁶ There is therefore not necessarily a sharp biological dividing line where “acute withdrawal” ends on one particular day and “protracted withdrawal” begins. Duration depends upon the medication, speed of withdrawal, individual response and other factors.¹˒⁶

[See: Protracted Withdrawal Syndrome]

Why Abrupt Cessation Can Be Dangerous

The severity of acute withdrawal is particularly important when medications are stopped abruptly.

NICE recommends that medicines associated with dependence or withdrawal symptoms should not normally be stopped abruptly, except in exceptional medical circumstances. Instead, withdrawal should generally involve slow, stepwise reductions adjusted according to the person's response.¹

For benzodiazepines, abrupt or excessively rapid withdrawal carries additional medical risks. Severe withdrawal can include confusion, delirium, psychotic symptoms and seizures, particularly following rapid withdrawal from high doses or high-potency benzodiazepines.³

For this reason, someone who has developed physical dependence should not interpret withdrawal symptoms as evidence that they simply need to “push through” a cold turkey.

Acute Withdrawal Is Not a Personal Failure

Developing withdrawal does not mean that somebody is weak, addicted or incapable of coping without medication. It means that their body has adapted to a pharmacologically active substance and is responding to a change in exposure.

Some people can reduce psychiatric medication relatively easily. Others require much smaller reductions over considerably longer periods. At present, clinicians cannot reliably predict beforehand who will experience the most severe antidepressant withdrawal symptoms.⁴

The goal should therefore not be to withdraw according to an arbitrary calendar, but to allow the individual response to help determine the pace. NICE recommends that subsequent reductions should be considered only when withdrawal symptoms have resolved or are tolerable.¹ [See also: Maudsley Deprescribing Guidelines ] 

References

1. National Institute for Health and Care Excellence. (2022). Medicines associated with dependence or withdrawal symptoms: Safe prescribing and withdrawal management for adults (NG215). https://www.nice.org.uk/guidance/ng215

2. Royal College of Psychiatrists. (2024). Stopping antidepressants. https://www.rcpsych.ac.uk/mental-health/treatments-and-wellbeing/stopping-antidepressants

3. Ashton, C. H. (2002). Benzodiazepines: How they work and how to withdraw (The Ashton Manual), Chapter III: Benzodiazepine withdrawal symptoms, acute and protracted. The Ashton Manual - Chapter III https://www.benzo.org.uk/manual/bzcha03

4. Royal College of Psychiatrists. (2024). Stopping antidepressants. RCPsych withdrawal guidance https://www.rcpsych.ac.uk/mental-health/treatments-and-wellbeing/stopping-antidepressants

5. Horowitz, M. A., & Taylor, D. (2022). Distinguishing relapse from antidepressant withdrawal: Clinical practice and antidepressant discontinuation studies. BJPsych Advances, 28(5), 297–311. https://doi.org/10.1192/bja.2021.62.

6. Ashton, C. H. (1995). Protracted withdrawal from benzodiazepines: The post-withdrawal syndrome. Psychiatric Annals, 25(3), 174–179.