Opioid withdrawal can be medically serious and should be supervised. If you or someone you know needs immediate help, SAMHSA's National Helpline is 1-800-662-4357 (free, confidential, 24/7).
If you suspect an overdose, call 911 immediately. Naloxone (Narcan) reverses opioid overdose and is available without prescription at most pharmacies.
What Is Opioid Use Disorder?
Opioid Use Disorder (OUD) is the DSM-5 clinical diagnosis for opioid addiction. It covers all opioids: prescription painkillers (oxycodone, hydrocodone, morphine, codeine), illicit opioids (heroin), and synthetic opioids (fentanyl, tramadol). The ICD-10 code is F11.20 for moderate or severe OUD.
The term "opioid addiction" has been largely replaced in clinical settings by "Opioid Use Disorder" to emphasise the medical nature of the condition and reduce stigma. OUD is a chronic brain disorder — not a moral failing — involving compulsive opioid-seeking behaviour that persists despite serious consequences.
OUD affects an estimated 16 million people worldwide. In the US, opioid overdose is the leading cause of accidental death. The shift to illicitly manufactured fentanyl — which is 50–100 times more potent than morphine and frequently found in counterfeit pills — has dramatically increased overdose risk even for experienced users.
The 11 DSM-5 Criteria for Opioid Use Disorder
A diagnosis requires 2 or more of the following criteria within a 12-month period. Note: tolerance and withdrawal alone (criteria 10 and 11) do not count toward diagnosis in people taking opioids solely under legitimate medical supervision — this distinguishes OUD from physical dependence that can occur with prescribed use.
-
1
Using more opioids than intended
Starting with one pill and taking three. Meaning to use for a few days after surgery and still using six months later. Once you start, you continue well past what you intended.
-
2
Persistent desire or repeated failed attempts to reduce or stop
You've told yourself repeatedly that you'll quit, use less, or only use on weekends — and each time, you've returned to previous levels or higher. Multiple sincere attempts that didn't last.
-
3
Spending large amounts of time obtaining, using, or recovering
Significant portions of your day are devoted to getting opioids (doctor shopping, finding dealers, waiting for delivery), using them, or being in a post-use state. This often means neglecting everything else.
-
4
Craving
Intense urge or desire to use opioids — often triggered by stress, environmental cues (people, places, smells associated with past use), emotional discomfort, or physical pain. Cravings can dominate cognition and become difficult to think past.
-
5
Failure to fulfil major role obligations
Missing work repeatedly, neglecting childcare, failing to meet financial responsibilities, or being unable to maintain commitments that were previously important because opioid use takes priority.
-
6
Continued use despite persistent social or interpersonal problems
Family members confronting you about your use, relationships damaged or ended, friendships lost — and continuing despite these consequences. The cost has been counted and paid, repeatedly.
-
7
Giving up important activities because of use
Quitting sports, hobbies, or social activities you previously valued. Withdrawing from people and activities that don't involve opioid use. Life increasingly narrows around obtaining and using.
-
8
Using in physically hazardous situations
Driving while impaired, using in environments where emergency help isn't available, mixing with other depressants (alcohol, benzodiazepines) despite knowing this increases overdose risk.
-
9
Continued use despite knowledge of physical or psychological harm
Knowing opioids are damaging your health, your relationships, your finances — and being unable to stop despite fully understanding the cost. The inability to stop despite wanting to is the defining feature of addiction.
-
10
Tolerance
Needing significantly more opioids to achieve the same effect. What once produced euphoria or pain relief now barely maintains functioning. Tolerance develops because opioid receptors downregulate in response to chronic stimulation.
-
11
Withdrawal
The characteristic opioid withdrawal syndrome when stopping or reducing: muscle aches, sweating, chills, goosebumps, severe anxiety and restlessness, insomnia, nausea, vomiting, and diarrhoea. Or using opioids to relieve or avoid withdrawal.
Severity Levels
Physical Signs of Active Opioid Use
Constricted Pupils
Opioids activate receptors that constrict the iris. Pinpoint pupils in normal or low light is a classic sign of opioid intoxication.
Drowsiness and Nodding
"Nodding out" — drifting in and out of consciousness mid-conversation or mid-activity. Slowed reaction time and impaired coordination.
Slowed Breathing
Opioids depress the respiratory drive. Slow, shallow breathing during intoxication. Respiratory depression is the primary mechanism of fatal overdose.
Weight Loss
Opioids suppress appetite and gastrointestinal function. Significant unexplained weight loss, often with poor nutrition and neglected eating.
Slurred Speech
During intoxication, speech becomes slow, slurred, and difficult to follow. Thought patterns may also appear disorganised or circular.
Track Marks
With IV use: bruising, scarring, or collapsed veins at injection sites (inner arm, back of hand). May rotate sites to avoid visible damage.
Opioid Withdrawal: What It Feels Like
Opioid withdrawal is famously severe — the phrase "kicking the habit" comes from the leg cramps and involuntary movements seen during opioid withdrawal. Understanding the timeline helps set realistic expectations.
Early onset (short-acting opioids)
Anxiety, restlessness, yawning, teary eyes, runny nose. These early symptoms are often mistaken for the flu and are the classic warning signs that withdrawal has begun.
Escalating symptoms
Muscle aches, goosebumps (piloerection — hence the phrase "cold turkey"), sweating, chills, nausea. Insomnia despite extreme fatigue. Anxiety becomes severe — many describe profound existential dread.
Peak withdrawal
The most severe phase. Vomiting, diarrhoea, severe cramping, uncontrollable leg movements ("restless legs"), extreme anxiety, insomnia. The body is actively trying to purge the substance. Dehydration risk from vomiting and diarrhoea is a medical concern.
Acute symptoms ease
Physical symptoms begin resolving. Appetite starts to return. Sleep improves marginally. Psychological symptoms (anxiety, depression, cravings) remain prominent.
Post-acute phase
Physical withdrawal is over, but psychological symptoms persist — low mood, anhedonia, sleep disruption, and cravings, especially in trigger situations. This is the highest-risk window for relapse.
PAWS (Post-Acute Withdrawal Syndrome)
Intermittent episodes of low mood, cognitive difficulty, reduced stress tolerance, and cravings as the opioid system continues recovering. Fluctuating rather than constant. MAT substantially reduces PAWS severity.
Opioids work by activating the brain's endogenous opioid receptors (mu, delta, kappa) which normally respond to endorphins and enkephalins. With chronic opioid use, the brain reduces its production of these natural opioids and downregulates receptor sensitivity to compensate.
When opioids are removed, the brain is left with: upregulated noradrenergic (norepinephrine) activity, depleted endogenous opioids, and over-sensitive pain pathways. This produces the anxiety, muscle aches, gastrointestinal distress, and hyper-arousal that characterise withdrawal — the body's pain and stress systems are firing without normal inhibition.
Clonidine (which reduces noradrenergic activity) helps withdrawal symptoms for this reason. Buprenorphine works by partially activating the opioid receptors to prevent severe withdrawal while being ceiling-limited so it can't produce full respiratory depression or euphoria at high doses.
Opioid Dependence vs. Opioid Addiction
This distinction matters clinically. Physical dependence is a physiological state — the body has adapted to opioids and will produce withdrawal symptoms when they're removed. This can happen to anyone taking opioids regularly for weeks or months, even at prescribed doses for legitimate pain. It is expected and does not, by itself, indicate a problem.
Opioid Use Disorder additionally involves: compulsive use despite harm, loss of control over use, continued use despite consequences, and the behavioural patterns described in the 11 DSM-5 criteria. Many people with chronic pain develop physical dependence without meeting criteria for OUD — they take their medication as prescribed, don't seek additional opioids, and stop when clinically appropriate.
The critical practical distinction: physical dependence is addressed medically through tapering. OUD requires addiction treatment — behavioural therapy, peer support, and usually medication-assisted treatment.
Treatment for Opioid Use Disorder
OUD is a treatable medical condition. Evidence-based treatment significantly improves outcomes and reduces overdose risk.
Buprenorphine (Suboxone, Subutex): A partial opioid agonist that occupies opioid receptors, preventing withdrawal and cravings without producing the full high of illicit opioids. Available from certified outpatient prescribers — no specialised clinic required. Most accessible form of MAT. Reduces overdose deaths by approximately 50%.
Methadone: A full opioid agonist dispensed daily at licensed methadone clinics. More tightly regulated than buprenorphine but often more effective for severe OUD. Reduces illicit opioid use and overdose deaths. Long-term MAT with methadone is associated with sustained recovery.
Naltrexone (Vivitrol): An opioid antagonist that completely blocks all opioid effects. Requires full detox first (no active opioid dependence). Monthly injectable form (Vivitrol) addresses adherence issues. Effective for highly motivated individuals, particularly in settings with strong social support.
Behavioural treatment: CBT, contingency management (incentivising abstinence), and peer support (12-step, SMART Recovery) are most effective when combined with MAT. Addressing trauma, co-occurring mental health conditions, and social determinants of health significantly improves long-term outcomes.
Frequently Asked Questions
What are the symptoms of opioid addiction?
Tolerance (needing more for the same effect), withdrawal (severe flu-like symptoms when stopping), using more than intended, failed quit attempts, preoccupation with obtaining opioids, and continued use despite serious harm. Physical signs include constricted pupils, drowsiness, and slowed breathing.
What does opioid withdrawal feel like?
Severe flu-like symptoms: muscle aches described as bones breaking, extreme anxiety and restlessness, profuse sweating, chills, goosebumps, nausea, vomiting, and diarrhoea. Symptoms peak at days 2–3 for short-acting opioids and largely resolve by day 7, though psychological symptoms persist for weeks to months.
What is the difference between opioid dependence and addiction?
Physical dependence (withdrawal on stopping) can occur with any long-term opioid use, including prescribed. Addiction (OUD) additionally involves compulsive use, loss of control, and continued use despite harm — regardless of how use started. You can be physically dependent without being addicted.
What medications treat opioid addiction?
Three FDA-approved options: buprenorphine (outpatient, partial agonist), methadone (clinic-dispensed, full agonist), and naltrexone (blocker, requires prior detox). All three significantly reduce overdose deaths and illicit opioid use. MAT is the evidence-based standard of care for OUD.
What is PAWS after opioid addiction?
Post-Acute Withdrawal Syndrome — intermittent low mood, anhedonia, sleep disruption, and cravings persisting for 6–18 months after acute withdrawal ends. PAWS is the primary relapse driver after detox. MAT substantially reduces its severity.
Tracking your opioid-free days?
Forge tracks your clean streak hour by hour, shows your body recovering in real time, and is built for the long haul — past 30 days, past 90, into the years.
Download free on iPhoneSources
- American Psychiatric Association. DSM-5-TR: Opioid Use Disorder. 2022. psychiatry.org
- Koob GF, Volkow ND. Neurobiology of addiction. Lancet Psychiatry. 2016;3(8):760–773. PMID 27475769
- SAMHSA. National Survey on Drug Use and Health. 2022. samhsa.gov