Withdrawal syndrome is the name for the condition caused by quitting substances.
When someone uses addictive substances for long periods, it causes lasting changes in the brain.
If an individual who has been using substances heavily stops using substances, especially in an abrupt fashion, the brain will go into withdrawal. This means that it is forced to rapidly adjust to being without the addictive substance.
Withdrawal syndrome includes a number of withdrawal symptoms, which vary in severity depending on a number of factors.
These factors are:
Withdrawal syndrome can last anywhere from a few days to a few weeks, depending on the above factors.
It can be caused by legal/prescription drugs, as well as illicit ones.
When someone stops taking substances under medical care, the doctor will help them to manage withdrawal symptoms. One way to ease withdrawal symptoms is by prescribing drugs like benzodiazepines, which are used for alcohol withdrawal.
During a home detox, individuals are left to manage withdrawal symptoms on their own. This can make withdrawal syndrome much more difficult to deal with.
Whether someone detoxes at home, or under medical care, acute withdrawal symptoms should be over after two weeks.
However, in some cases, post-acute withdrawal symptoms can occur after the initial period of withdrawal.
Post-acute withdrawal symptoms can last for as long as a year, and include psychological symptoms such as brain fog and fluctuating moods, as well as physical symptoms such as insomnia.
Post-acute withdrawal syndrome, or PAWS, refers to the symptoms of withdrawal which continue after the initial phase. Though not as physically uncomfortable as acute withdrawal symptoms (such as nausea, vomiting, sweating etc.) these post-acute withdrawal symptoms can still pose a risk to an individual’s continued abstinence.
Knowing the symptoms of PAWS, and techniques to deal with them, can be very useful for someone who has recently stopped using substances.
PAWS is often said to come in waves: you may go through a long period without any symptoms, and then suddenly experience PAWS symptoms which last for a few days.
There is a lot of variance in how people experience PAWS, but some common symptoms include:
If you are experiencing any of these symptoms, and you think you may be suffering from PAWS, speak to your doctor.
PAWS is not limited to specific substances, and, in theory, can occur with any substance. However, it has been linked with the following substances:
Though PAWS has been the subject of some research, it is yet to be recognised in the Diagnostic and Statistical Manual of Mental Disorders, which is the most reputable reference book for addiction and mental health.
So, is PAWS real? What evidence is there that it exists?
One study, by S L Satel et al., looked at clinical data and laboratory research regarding withdrawal from alcohol, opiates and stimulants. It argued that there is insufficient evidence to recommend PAWS for inclusion in the DSM-IV (the penultimate edition of the reference book cited above).
The reason given by Satel et al. was this:
‘Symptoms extending beyond the period of acute withdrawal in alcohol and opiate dependence have been fairly consistently described. Nevertheless […] There is insufficient documentation to justify inclusion of protracted withdrawal in DSM-IV because of methodologic limitations of the studies and lack of consensus definition of the term itself.’ 
In essence, then, PAWS has been described by many people in recovery but has yet to receive sufficient scientific study to be accepted by the medical community.
Just as the existence of PAWS has been the subject of some controversy in the scientific community, there is still debate around the causes of PAWS.
One of the difficulties is that PAWS seems to vary so much from person to person. If PAWS had a set of very consistent symptoms, perhaps it would be easier to isolate a specific cause.
However, symptoms are not consistent, and are liable to come and go, such that individuals in recovery may experience PAWS symptoms for a few days and then be symptomless for months.
One point on which scientists seem to agree, by and large, is that the stress response plays an important part in the development of PAWS. However, as we will see, there is disagreement about what triggers the stress response.
Perhaps the simplest explanation for PAWS is that the very experience of giving up a substance causes stress, and this stress makes psychological symptoms of withdrawal worse. Relapse leads to more stress, which keeps the cycle of withdrawal symptoms and PAWS symptoms going.
Another explanation for PAWS is that it is caused by changes in habits. On this understanding, stress is caused by the loss of certain habits built up during a period of substance use. The loss of these habits, coupled with the associated stress of habit-loss, leads to an exacerbation of psychological symptoms such as depression and tiredness.
A third explanation focuses on changes in the body. The body gets used to a steady supply of drugs or alcohol; it takes time to readjust, leading to withdrawal symptoms. This is often the explanation given for acute withdrawal symptoms; however, it might also explain PAWS in some cases. For example, someone who was addicted to CNS depressants might find that their heart rate takes longer than two weeks to return to normal.
A fourth, and final explanation focuses on changes in the brain. Substance use leads to changes in the brain which cannot be undone immediately; there may be long-lasting changes which take months to go back to normal. If this is the case, it would go some way towards explaining psychological symptoms like mood swings which are typical of PAWS. Click here for more information about changes in the brain and how they impact the ability to cope with stress.
Given that PAWS symptoms are mainly psychological, treatment focuses on how to cope with these psychological symptoms and prevent them from leading to relapse.
Some suggestions for treatment include:
 Budney AJ, Hughes JR, Moore BA, Vandrey R. Review of the validity and significance of cannabis withdrawal syndrome. Am J Psychiatry. 2004 Nov;161(11):1967-77. doi: 10.1176/appi.ajp.161.11.1967. PMID: 15514394.
 Satel SL, Kosten TR, Schuckit MA, Fischman MW. Should protracted withdrawal from drugs be included in DSM-IV? Am J Psychiatry. 1993 May;150(5):695-704. doi: 10.1176/ajp.150.5.695. PMID: 8097618.
 The Influences of Diet and Exercise on Mental Health Through Hormesis. Fernando Gomez-Pinilla