Legal Highs Addiction
Medically reviewed and approved by: Dr Mann, GP
Medical review date: 15 October 2026
Legal highs is an older term for a wide range of new psychoactive substances (NPS). The name can be misleading: many are illegal to supply, some are controlled drugs, and none should be assumed safe because of the way they are marketed. If your use has become difficult to control, confidential help is available. [1, 2]
For confidential advice about treatment options, contact Step by Step Recovery on 0800 170 1222 or request an assessment.
What are Legal Highs?
New psychoactive substances are drugs that can change mood, perception, alertness or behaviour. They include synthetic cannabinoids, such as products sold as Spice, and synthetic stimulants, including some cathinones. Different products can act in very different ways. The same street name or packaging does not guarantee the same ingredients or strength. [1, 2, 3]
“Legal highs” is not a clinical diagnosis or a reliable description of their legal status. Treatment starts by identifying what someone may have taken, how often they use it, and any physical or mental health problems. [1, 3]
Are Legal Highs Legal in the UK?
The Psychoactive Substances Act 2016 generally makes the production, supply, import and export of psychoactive substances covered by the Act criminal offences, subject to statutory exemptions. Simple possession is not generally an offence under that Act, except in a custodial institution. However, many specific drugs are separately controlled under the Misuse of Drugs Act 1971, where possession can be an offence. The law depends on the substance and circumstances. [2]
Types of Legal Highs
Synthetic cannabinoids, including Spice
Synthetic cannabinoids act on cannabinoid receptors but are not the same as natural cannabis. Their effects can be much less predictable and may include severe agitation, confusion, collapse, seizures and psychotic symptoms. Dependence and withdrawal can occur with repeated use. [3, 4]
Synthetic stimulants, including cathinones
Some synthetic cathinones produce stimulant effects such as increased energy and alertness. Risks can include rapid heartbeat, overheating, agitation, paranoia and, in some cases, serious cardiovascular or psychiatric complications. Repeated use can become compulsive. [3, 5]
Other new psychoactive substances
Other NPS may have sedative, hallucinogenic or opioid-like effects. Their risks and withdrawal management differ substantially. It is unsafe to assume that all legal highs cause the same symptoms or need the same detox programme. [1, 3]
How Do I Know If I Am Addicted to Legal Highs?
Not everyone who uses a new psychoactive substance develops an addiction. Signs of a possible substance use disorder include:
- Using more often or in larger amounts than intended.
- Repeated unsuccessful attempts to cut down or stop.
- Strong cravings or spending substantial time obtaining, using or recovering from a substance.
- Continuing to use despite harm to health, relationships, work or finances.
- Giving up important activities because of drug use.
- Developing tolerance or withdrawal symptoms with some substances.
Physical dependence and addiction are not identical. A professional assessment considers the pattern of use and its impact rather than relying on any one symptom. [3]
Signs and Effects of Legal Highs Use
Because different new psychoactive substances can have very different effects, the signs of problematic use can vary. These are some of the common behavioural and physical indicators.
Behavioural signs
- Secrecy about drug use or unexplained changes in routine.
- Missing commitments or withdrawing from family and friends.
- Continuing use after frightening or harmful experiences.
Physical signs
- Changes in sleep, appetite, energy or coordination.
- Palpitations, sweating or nausea, depending on the substance.
- Episodes of marked drowsiness, confusion or collapse.
Psychological signs
- Anxiety, panic, irritability or low mood.
- Paranoia, hallucinations or severe agitation.
- Cravings and difficulty controlling use.
These signs are not specific to NPS and may have other causes. Medical assessment is important if symptoms are severe, new or persistent. [3, 4, 5]
Legal Highs and Overdose
The risks depend on the actual substance, dose, other drugs taken and the person’s health. Unknown ingredients can make emergencies harder to assess, but emergency teams can still provide effective supportive treatment. Do not delay seeking help because the drug is unidentified. [1, 3]
Call 999 immediately if someone has a seizure, severe chest pain, difficulty breathing, collapses, becomes unresponsive, has dangerously high body temperature or is severely confused or agitated. Tell the ambulance crew what may have been taken. If unconscious but breathing normally, place them in the recovery position; follow emergency-service instructions. [1, 3]
Legal Highs Withdrawal
There is no single “legal highs withdrawal syndrome”. Withdrawal varies by drug type, frequency of use and co-occurring dependence on alcohol or medicines. For example, stopping regular synthetic cannabinoid use may lead to anxiety, irritability, disturbed sleep, sweating and cravings. After heavy stimulant use, fatigue, low mood and sleep changes may be prominent. Some sedative or opioid-like substances can cause medically serious withdrawal. [3, 4, 5]
Do not attempt to manage severe symptoms alone. Anyone with confusion, hallucinations, seizures, suicidal thoughts or significant physical illness needs urgent assessment. People who may also be dependent on alcohol, benzodiazepines or GHB require particular care because withdrawal from those substances can be dangerous. [3]
Physical Health Risks
- Heart palpitations
- Extreme changes in body temperature
- Nausea and vomiting
- Poor coordination or slurred speech
- Seizures, coma or loss of consciousness
- Potentially fatal overdose
Mental Health Risks
- Mood swings and agitation
- Panic attacks and confusion
- Paranoia
- Hallucinations
- Psychosis
- Worsening anxiety, depression or stress
- Overdose symptoms require immediate emergency help
Because the contents of legal highs can be uncertain, medical treatment can be more difficult in an emergency. If you think someone may be experiencing an overdose, contact emergency services immediately.
Legal Highs Addiction Treatment
Treatment should be matched to the substance, the severity of use, mental and physical health, and personal circumstances. An initial assessment should identify immediate risks and whether specialist medical or psychiatric care is required. [3]
Assessment and withdrawal support
There is no universal medication or standard detox schedule for all NPS. Some people need monitoring and practical support; others need treatment for a specific withdrawal syndrome or referral to a hospital or specialist service. Medication, where appropriate, must be prescribed for the individual clinical situation. [3]
Psychological therapies
Psychological and behavioural support can help people understand triggers, manage cravings, strengthen coping skills and plan for relapse prevention. For stimulant-type drugs, psychosocial interventions are central to treatment. Support may also be needed for anxiety, depression, trauma or other mental health problems. [3]
Residential rehabilitation and outpatient care
Residential rehabilitation can provide structure and focused therapeutic support for people whose needs are suited to that setting. Others may benefit from community or outpatient treatment. Residential rehabilitation is not a substitute for emergency or hospital treatment when someone is medically unstable or experiencing acute psychosis. [3]
Important: Do not try to manage severe withdrawal or overdose symptoms alone. If someone is seriously unwell after taking a legal high, seek urgent medical help.
How to Get Help With Legal Highs Addiction
If you are worried about your own use or someone else’s, you can speak to your GP, local NHS-commissioned drug and alcohol service or Step by Step Recovery. We can discuss your circumstances confidentially and explain available assessment and treatment pathways. Admission and the most appropriate level of care depend on clinical assessment and the services available at the time.
Call Step by Step Recovery on 0800 170 1222 or request a confidential assessment.
Common Questions
FAQs
Here are some common questions based on the information already covered on this page. If you would rather speak to someone privately, our team is available to help.
Are legal highs safe because they are sold online?
No. Online sale or familiar packaging does not establish safety, purity or legality. Ingredients and potency can be uncertain. [1, 2]
Can Spice cause addiction?
Yes. Some people develop compulsive use and dependence on synthetic cannabinoids, and withdrawal symptoms may occur after regular use. [4]
Do legal highs always need a medical detox?
No. Treatment depends on the substance and the person’s risks. Some people need supportive care and psychological treatment; others require specialist medical assessment or inpatient care. [3]
Can legal highs cause psychosis?
Some NPS, including synthetic cannabinoids and stimulants, can cause paranoia, hallucinations or psychotic symptoms. New or severe symptoms require prompt medical assessment. [4, 5]
How long does withdrawal last?
There is no reliable single timeframe because the term covers different drugs. Symptoms and recovery vary with the substance, pattern of use and individual health. [3]
Can I get help without going into residential rehab?
Yes. Community drug services, outpatient treatment and psychological support may be appropriate. Residential treatment is one option, not a requirement for everyone. [3]
Other Addictions We Treat
New psychoactive substances are often designed to mimic the effects of other drugs. Step By Step Recovery also provides information and treatment support for other substance addictions.
Prescription Drug Addiction
Learn more about prescription drug addiction, warning signs and treatment support.
Cannabis Addiction
Learn more about cannabis addiction, dependency and treatment support.
Cocaine Addiction
Learn more about cocaine addiction, its effects and available treatment support.
Three specialised Clinics
Drug and Alcohol Treatment in Essex, London and Birmingham
Step By Step Recovery operates three specialist clinics providing residential detox and rehabilitation in Essex and outpatient treatment in London and Birmingham. Wherever you are in the country, help is closer than you think.
RESIDENTIAL
Essex Clinic
- 1A Southchurch Avenue, Southend-On-Sea, SS3 9BA
- 01702 296 006
outpatient
London Clinic
- Finsgate House, 5 Cranwood Street, London, EC1V 9EE
- 0207 118 9400
outpatient
Birmingham Clinic
- Suite 201c Bradford Court Business Centre, 123 – 131 Bradford Street, Birmingham, B12 0NS
- 0121 401 1700
Clinical References
[1] FRANK, New psychoactive substances — https://www.talktofrank.com/drug/new-psychoactive-substances
[2] Home Office, Psychoactive Substances Act 2016: guidance for retailers — https://www.gov.uk/government/publications/psychoactive-substances-act-guidance-for-retailers/psychoactive-substances-act-2016-guidance-for-retailers
[3] Department of Health and Social Care, Drug misuse and dependence: UK guidelines on clinical management — https://www.gov.uk/government/publications/drug-misuse-and-dependence-uk-guidelines-on-clinical-management
[4] ACMD, Synthetic cannabinoid receptor agonists — https://www.gov.uk/government/publications/synthetic-cannabinoid-receptor-agonists
[5] ACMD, Synthetic cathinones: updated harms assessment — https://www.gov.uk/government/publications/synthetic-cathinones-an-updated-harms-assessment/synthetic-cathinones-an-updated-harms-assessment-accessible
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