Post-Acute Withdrawal Syndrome

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What Is Post-Acute Withdrawal Syndrome?

Post-acute-withdrawal syndrome (PAWS) refers to a constellation of symptoms experienced by some individuals who are addicted to alcohol or certain drugs after a prolonged period of withdrawal.

PAWS is also known by several similar terms, including post-withdrawal, protracted withdrawal, prolonged withdrawal syndrome, and protracted abstinence.

PAWS is separate and distinct from the acute phase of withdrawal, which typically occurs in the first two weeks after drug cessation.

Acute withdrawal has long been studied by addiction researchers and, dependent on the type of drug from which withdrawal is occurring, is characterized primarily by physical symptoms. These symptoms may include:

  • Tremors.
  • Seizures.
  • Autonomic nervous system hyperactivity (sweating, nausea, rapid heart rate).
  • Intense drug craving.

In contrast to acute withdrawal, symptoms of PAWS generally occur 2 months or more after drug cessation and are primarily psychological in nature, affecting a person’s mood, sleep patterns, and response to stress. The symptoms of PAWS generally last for several months in people recovering from addiction, though they can disappear in a matter of weeks or, in rare cases, persist for a year or more.

Symptoms of PAWS

There are a myriad of symptoms associated with PAWS. Though each of these is fairly common among people withdrawing from drugs and alcohol, the exact number, combination, and timing of specific symptoms is different for each person. Physical differences between people, as well as differences in the types of drugs used and the amount and frequency of use all affect each individual’s experience of PAWS.


Mood swings: The brain of a chronic drug user, including patients taking medications under their doctor’s supervision, has become adapted to a constant supply of a mood-altering substance. When that substance is removed, periods of mania or depression can occur for no apparent reason while the brain rebalances itself.

Anhedonia: Although they work in different ways, virtually all addictive drugs, and many medications like antidepressants, have the end result—in the short term, at least—of boosting neurotransmitters and neural pathways that make the user feel good. Otherwise, why would people take them? Once these drugs and medications are stopped, however, it can take some time for the brain to produce normal levels of these feel-good chemicals on its own again. Until it does, an individual may find that nothing seems fun or interesting anymore – even activities they used to enjoy.

Anxiety: For addicts and patients alike, cessation of a drug or medication is a major life change. Therefore, it is understandable that there can be a great deal of anxiety, and even panic attacks, that accompany this shift. Additionally, drugs such as alcohol and BZDs that chronically inhibit brain activity result in a hyperexcitable, anxiety-prone state when they are stopped.

Insomnia: Many psychoactive drugs and medications affect sleep patterns, and the brain adapts to long-term use. Once these drugs are stopped, it can take time to re-establish healthy sleep patterns.

Sleep disturbances: Subconscious desires to take alcohol or drugs, or to resume some aspect of the drug-using lifestyle, can manifest themselves in vivid, realistic dreams. Though such dreams may be very disturbing to a person in recovery, they are not a warning of impending relapse, but simply a reflection of how deeply the drug-taking compulsion can be ingrained in the mind.

Cognitive impairment: Like mood changes, this is another symptom of neurotransmitter imbalance. It is important to remember that difficulties in thinking clearly and maintaining concentration are usually temporary and not a sign of permanent brain damage.

Depression and fatigue: Many people who stop chronic drug habits or long-term medications experience such intense feelings of depression and fatigue that they fit the criteria for Major Depressive Disorder or Chronic Fatigue Syndrome. Unlike these conditions, however, these symptoms are a phase of readjustment in the brain and generally diminish without treatment over time.

Drug cravings: People with PAWS often have intermittent cravings for the drug or medication that they took before. Because the most intense physical withdrawal symptoms have subsided, the individual may feel physically healthy but continue experiencing negative psychological symptoms which make the return to drug use seem appealing.

Sensitivity to stress: Many people dealing with the effects of PAWS find that their threshold for daily stress is very low. Trivial irritations or setbacks can feel like the end of the world. Considering that these individuals have given up what has been, for months or years, their primary tool for coping with life’s stresses, this difficulty is easy to understand. New life skills must be learned, and even dealing with normal emotions brought on by stress can take time.

These are some of the most common manifestations of PAWS but not an exhaustive list. One unifying theme among these symptoms is that they all impair various facets of an individual’s emotional state, or their “affect.” Another common aspect of these symptoms is that they are intermittent and may come and go over days and weeks, and they generally do not impact a person to the same extent over the entire course of their withdrawal.

Common Drug Classes Associated with PAWS

Some classes of substances are more commonly associated with a protracted withdrawal period than others following relatively prolonged abstinence from the drugs. However, as noted above, few rigorous scientific studies have been conducted into the etiology of PAWS, so the following list of drugs that cause this syndrome is not exhaustive.

Because symptoms of PAWS are thought to be caused by changes in brain function induced by psychoactive drugs that persist long after cessation of drug-taking, it is possible that any such drug, if taken long enough at a high enough dose, could result in PAWS during the recovery process.


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Of all drugs, prolonged withdrawal resulting from ceasing alcohol intake has received the most scientific attention. Studies examining symptoms now attributed to PAWS have been published in medical journals since the 1990s.

Alcohol is a sedative drug and works, in part, by activating ?-aminobutyric acid (GABA) receptors in the brain. Increased GABA activity inhibits, or decreases, brain activity overall, and the brain adapts to counteract chronic inhibition. An individual who has become dependent on alcohol will find that their nervous system is overactive, or hyperexcitable, when they stop drinking.

Initially, this hyperexcitable state can lead to seizures and tremors, but less severe symptoms such as sleep disturbances, mood swings, anxiety, and lack of sexual interest can continue for several months or even years. Though gradually decreasing the amount of alcohol ingested over time, or tapering, can help reduce the intensity of acute withdrawal, this strategy appears to be much less effective for the longer-lasting symptoms of PAWS.


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Similar to alcohol’s mechanism of action, benzodiazepines (BZDs) such as diazepam (Valium) or alprazolam (Xanax) are GABA receptor activators, and their chronic use also causes the brain to adapt by switching to a hyperexcitable state. Withdrawal symptoms are very common with this class of drugs, even in patients who take them strictly as directed and under a doctor’s supervision.

As with alcohol, tapering can help acute withdrawal, but is not very effective for avoiding PAWS. This can be very difficult for patients who have taken BZDs for anxiety and panic disorders, since anxiety is a very common symptom of PAWS. Symptoms of protracted withdrawal from these drugs can look like symptoms of other disorders such as schizophrenia, depression, panic disorders, and OCD.


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Most modern antidepressant drugs are selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac) or serotonin-norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine (Effexor). They work to raise the levels of one or both of these neurotransmitters (serotonin and norepinephrine) in the brain by blocking their reabsorption by nerve cells.

The exact mechanism of how these drugs work to improve depression in patients is the subject of scientific debate, but almost certainly involves adaptive changes in the brain since there is a delay of several weeks to a month before patients derive benefits from these medications. It is unsurprising, therefore, that long-term effects are commonly reported when patients stop taking these medications.


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Long-term symptoms of opiate withdrawal are commonly reported in individuals recovering from opioid addictions. Both pharmaceutical and illicit opioid painkillers such as oxycodone (OxyContin), hydrocodone (Vicodin), codeine, or heroin, can elicit PAWS symptoms such as anxiety, fatigue, and sleep disturbances in dependent individuals when they stop taking these drugs.

All opioid drugs work by activating opiate receptors in the brain and spinal cord, which modulates perceived pain levels, induces a feeling of well being, and produces, at high doses, a euphoric high.

The body adapts to chronic overstimulation of opioid receptors by increasing the number of them on the surface of brain cells, so that more receptors need to be activated by opioid drugs to produce an effect.

Also, the amount of endorphins, the natural chemicals that activate opiate receptors, is decreased in chronic opioid drug users as the body compensates for overstimulation of this system. These adaptations by the nervous system reduce opiate signaling to the brain and have been linked to increased pain sensitivity and mood disturbances in individuals addicted to opiates. These changes can take months or even years to completely reverse themselves and for opiate signaling to return to normal levels. Some researchers have been experimenting with indirectly increasing opiate signaling in patients recovering from addiction with low-dose naloxone (Narcan) to alleviate symptoms of PAWS.


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Stimulant drugs such as cocaine and amphetamine provide some of the clearest evidence that PAWS is a true medical condition, and not simply an extension of acute withdrawal.

The psychological symptoms of PAWS such as paranoia, anxiety, impulse control problems, depression and other emotional regulation issues are frequently observed in chronic users who stop stimulants suddenly:

Similar to other drugs, these symptoms are thought to be caused by adaptations in the brain to long-term stimulant use, and they can take several months or longer to resolve themselves.

Other Drugs

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It is not at all certain that PAWS is restricted only to certain classes of drugs.

It has been proposed that marijuana, antipsychotic medications, and anabolic steroids, in particular, can also induce PAWS-like symptoms in those who stop taking these drugs after a period of chronic use.

Although the examples listed above reflect the most commonly encountered causes of PAWS, the lack of recognition of this syndrome by medical societies and diagnostic guides means that many physicians are simply not looking for it in their patients and may miss it altogether.

Risk Factors for PAWS

Individuals in recovery—even those with similar drug histories—report widely variable and unique experiences as they present in PAWS. Many factors can influence the types of post-acute withdrawal symptoms that manifest and the intensity with which they are experienced. These factors include:

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  • The pattern of substance abuse.
  • Duration of the addiction.
  • Intensity of the drug use.
  • Genetics.
  • Physiology.
  • Psychological makeup.
  • The existence of other physical or psychological conditions.

History of drug use is the best-known risk factor for PAWS. Those who have used psychoactive substances for longer, more often, and at higher doses are more likely to experience PAWS, and the symptoms will be more intense than those whose drug use was lighter.

Genetics and physiological factors are very likely to play a role, however, since PAWS can manifest differently in two individuals who have used the same substance in the same manner. Because so little research has been conducted into this syndrome, it is not possible to predict in advance how someone will be affected.

The Challenges of PAWS

In addition to the subtle and unpredictable symptoms of PAWS, individuals in recovery frequently experience challenges stemming from the fact that this syndrome is not universally recognized in the medical community and little scientific research has been conducted into the causes of and treatments for this condition.

Though its existence is widely accepted among recovery professionals, PAWS is not officially recognized by any medical associations, nor is it listed in the American Psychiatric Association’s Diagnostic Statistical Manual of Mental Disorders (DSM), the standard classification of mental disorders used by all mental health professionals in the US.


What to Expect

Symptoms of PAWS will manifest themselves after the end of acute withdrawal, but can appear anytime within several weeks to several months after drug cessation. The drug classes discussed above have different long-term effects on the brain, and the symptoms of PAWS will be different, depending on which substance, or combination of substances, was used.

Effects of this syndrome may then continue for anywhere from 2-3 months to several years. There are anecdotal reports of individuals who continue experiencing prolonged withdrawal for the rest of their lives, though this appears to be extremely rare.

It is important to remember that symptoms of PAWS come and go. The vast majority of people do not experience excessive fatigue or anxiety for months or years on end, without a break. Instead, these symptoms fluctuate, lasting days or weeks, and are separated by periods that are symptom-free.

PAWS: A Normal Part of Recovery

Though it can be upsetting, PAWS is a normal part of the recovery process from unhealthy dependence and addiction. It is important to be aware of the symptoms of prolonged abstinence from substance abuse, because some of these negative symptoms can be discouraging to recovering individuals and tempt them to return to drug use.

Steps that can be taken to manage PAWS and improve your well being during recovery include:

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  • Educating yourself. Becoming aware and educated about both acute and post-acute withdrawal so you know what to expect as you navigate the recovery process.
  • Focusing on positive changes and achievements. Although it is normal to focus on continued difficulties caused by PAWS, you should not lose sight of how recovery is changing your life for the better.
  • Stay active. Physical activity and exercise help your body and brain heal more quickly—bolstering immune system activity and restoring healthy balance to neurotransmitter levels—and can reduce anxiety and stress, as well as help you sleep better in the long-term.

Most importantly, be patient and take it easy on yourself. Though the experience of PAWS can be unpleasant and frustrating for both the recovering person and his friends and family, these symptoms will subside with time. Patience and understanding are therefore the keys to successfully navigating PAWS and learning how to live a healthy and happy life in recovery.

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Amanda Lautieri is a Senior Web Content Editor at American Addiction Centers and an addiction content expert for She holds a bachelor's degree and has reviewed thousands of medical articles on substance abuse and addiction.
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