Polysubstance Use: Dangers, Withdrawal and Treatment

Written by the medical team at Day One Rehabilitation Center, Nakhon Nayok, Thailand · Medically reviewed by Dr. Pichayut Kasemphakdeephong (Psychiatrist)

Polysubstance use means using two or more substances at the same time or close together — for example, drinking alcohol along with sleeping pills, using crystal meth (ice) with ketamine, or using heroin along with another substance. Not everyone uses them at exactly the same time; some people alternate substances depending on the situation, such as using a stimulant to stay awake and then a depressant to help fall asleep.

Some people start with just one substance and gradually add others — to boost the effect, ease unpleasant side effects from the first substance, help them sleep, or manage withdrawal. Others may unknowingly take more than one substance because of products with inconsistent or unknown ingredients.

What makes polysubstance use concerning is that the effects of different substances don’t simply add up or cancel out in a predictable way. Combining them can produce more severe, harder-to-predict symptoms, and makes assessing withdrawal and planning treatment more complex. Treatment therefore needs to look at the whole pattern of use, physical health, mental health, and the reasons behind reliance on each substance — not just treat whichever substance the family thinks is the main problem.

What Is Polysubstance Use?

Polysubstance use doesn’t just mean physically mixing two substances and taking them at once — it also includes using multiple substances within a similar timeframe.

Examples that may occur include:

Drinking alcohol together with sleeping pills or anti-anxiety medication
Using heroin or other opioids together with alcohol
Using crystal meth (ice) together with ketamine
Using crystal meth (ice) or cocaine, then taking a sleeping pill to fall asleep
Using GHB or GBL together with alcohol
Using cannabis together with alcohol or other substances
Using multiple party drugs in a single night
Regularly using cigarettes or vapes alongside other drugs

Some people don’t feel like they’re “addicted to multiple things,” because there’s only one substance they use daily. But if another substance is used to boost the effect, tone it down, or manage symptoms afterward, that’s still important information the treatment team needs to know.

For example, someone who uses crystal meth (ice) at night and then takes a sleeping pill to fall asleep might think of the sleeping pill as just an aid, but from a treatment standpoint, both need to be assessed — because once the person stops, the symptoms that appear may come from more than one substance.

Why Polysubstance Use Is More Dangerous Than You Might Think

Each substance acts differently on the brain, heart, breathing, and nervous system. When several are used together, the resulting effects can be hard to predict.

Combining Two Depressants

For example, alcohol combined with sleeping pills, or opioids combined with benzodiazepines. These substances can compound each other’s depressant effects, causing extreme drowsiness, confusion, loss of consciousness, and dangerously slowed breathing.

Thinking “I’ve combined them before and was fine” doesn’t mean the next time will be safe — the dose, physical condition, and whatever else is already in the body can vary each time.

Combining Two Stimulants

Using more than one stimulant, such as crystal meth (ice) with cocaine, puts extra strain on the heart and circulatory system, causing a racing heart, high blood pressure, elevated body temperature, agitation, and an increased risk of severe complications.

On the mental health side, it can cause severe anxiety, paranoia, insomnia, hallucinations, or psychotic symptoms, especially with continuous use and prolonged sleep deprivation.

Stimulants and Depressants Don’t Cancel Each Other Out

Some people believe that using a stimulant followed by a depressant will cancel out the effects and make it safer, but in reality both substances continue acting in the body.

One substance can mask the sensations of the other, causing the user to underestimate how intoxicated they really are — feeling like they aren’t drunk or drowsy yet, and using more as a result. As the effect of one substance wears off, the effect of the other can suddenly become dominant and turn dangerous.

Signs That Polysubstance Use Is Becoming Hard to Control

Families may not know the names of every substance a person is using, but they can watch for changes in behavior and health, such as:

Regularly using more than one substance
Needing another substance to counteract the effects of the first
Using a stimulant to stay awake, then something else to fall asleep
Increasing dose or frequency
Sleeping at odd hours, going without sleep for several nights, or sleeping unusually long
Rapid mood swings
Increasing irritability, anxiety, or paranoia
Hallucinations or psychotic symptoms
Declining memory and concentration
School or work performance suffering
Financial or relationship problems
A previous loss of consciousness or medical emergency from substance use
Trying to stop but relapsing

Sometimes a person tells their family they’ve quit one substance, but has actually increased their use of alcohol, cannabis, sleeping pills, or another substance instead. When this happens, the whole cycle of substance use needs to be assessed, not just whether the original substance has stopped.

If someone is unconscious, cannot be woken, is breathing slowly or abnormally, is having a seizure, has chest pain, is severely confused, or has severe psychotic symptoms, seek emergency medical help — do not wait for the symptoms to resolve on their own.

Withdrawal From Multiple Substances: Why You Shouldn’t Stop Without an Assessment

Stopping several substances at once can be more complicated than stopping just one, because each substance has a different withdrawal timeline and severity.

Some cause extreme fatigue, excessive sleep, low mood, or intense cravings, while others — such as alcohol, benzodiazepines, and GHB/GBL — can cause severe and dangerous withdrawal in people who have become physically dependent.

Before stopping, it’s important to gather as much information as possible about:

What substances are being used
How much and how often each one is used
How long they’ve been used
When the last use was
What withdrawal symptoms have occurred before
Any history of seizures, confusion, or loss of consciousness
Any existing medical or psychiatric conditions
Any other medications or substances used regularly

This information helps the treatment team assess which substance carries the highest withdrawal risk, what symptoms to watch for, and what level of care is needed.

So if a family member regularly uses multiple substances, they should not simply confiscate everything and force an immediate stop without knowing the risks — especially when alcohol, sleeping pills, anti-anxiety medication, or GHB/GBL are involved.

Treating Polysubstance Use Requires More Than Just Stopping the Drugs

Treatment should start with assessing every substance being used, even ones the patient feels “aren’t a problem,” because each substance can play a different role in the cycle of addiction.

For example, someone might use crystal meth (ice) for energy and to socialize, alcohol to reduce anxiety, and a sleeping pill afterward to fall asleep. If treatment only addresses the crystal meth without understanding why they also rely on alcohol and sleeping pills, the same cycle can keep going.

After withdrawal is complete and the person is medically stable, recovery should cover key areas such as craving management, identifying triggers, cognitive and behavioral change, sleep, stress management, and building routines that don’t depend on substances.

If there’s a co-occurring psychiatric condition — depression, anxiety disorder, bipolar disorder, ADHD, or psychotic symptoms — it should be assessed and treated alongside the substance use, because mental health problems and substance use can influence each other.

Medication for addiction also depends on the specific substance — there is no single medication that treats every kind of addiction at once. People with opioid, nicotine, or alcohol addiction may have different medication options available, while some substances have no direct medication treatment at all. Treatment planning therefore requires assessing each problem separately and then bringing them together into one unified plan.

What to Do When a Family Member Uses Multiple Substances but Won’t Admit It’s a Problem

Families don’t need to first prove exactly “how many substances” the person is addicted to before seeking help, since they often only know part of the real picture.

Conversations should start from what has actually been observed, for example: “I’ve noticed you’ve barely slept for several nights lately, and then some days you sleep for a really long time — I’m worried about your health.” Or: “Last time you lost consciousness after using several things together, so I’d like you to get checked out to see how your body has been affected.”

Avoid opening the conversation by interrogating them about exactly what they’re using, or forcing them to immediately admit they’re addicted, since this can push them to hide more.

The first goal can simply be getting them to agree to see a specialist to assess their health and pattern of substance use. There’s no need to wait for full acceptance before starting treatment.

If the person isn’t ready, the family can come in for counseling on their own first, to help gather information, assess risk, and plan an appropriate way to talk to them.

Treating Polysubstance Use at Day One Rehabilitation Center

People who use multiple substances are a group that can particularly benefit from residential treatment, especially when they can’t control their use, relapse often, have a co-occurring psychiatric condition, or their usual environment is full of triggers and easy access to substances.

At Day One Rehabilitation Center, the assessment doesn’t focus on just the “main” substance — it gathers information on every substance being used, how often, how they’re combined, any history of withdrawal or overdose, along with an evaluation of physical health, mental health, and current medications.

In the early stage, the treatment team assesses withdrawal risk and manages symptoms as needed. If a condition requires a higher level of medical care than the center can provide, the person is referred elsewhere for safety before entering the rehabilitation process.

Once the person is medically stable, the program focuses on individual therapy, group therapy, psychiatric assessment and treatment of co-occurring conditions, structured daily routines, exercise, and training in managing cravings and triggers.

A key part of treating polysubstance use is understanding how the different substances relate to each other — what’s used when stressed, what’s used to socialize, what’s used to sleep, and which substance tends to lead to using another. Understanding these cycles makes it possible to build a precisely targeted relapse-prevention plan.

Residential treatment also separates patients from substances, friend groups, sources, and triggers in the early stages, giving them time to recover both physically and mentally while preparing a plan for returning to real life after the program ends.

Frequently Asked Questions About Polysubstance Use

Does polysubstance use only count if the substances are taken at the exact same time?

No. Using two or more substances at the same time or within a similar time frame both count as polysubstance use — for example, using crystal meth (ice) at night and then taking a sleeping pill afterward.

Do stimulants and depressants cancel each other out when used together?

No, they don’t cancel out. Both substances continue acting on the body, and one can mask the effects of the other, leading users to think they can safely use more. This makes the outcome unpredictable and raises the risk of complications.

Does alcohol count as one of the substances you need to tell your doctor about?

Yes, it does. If alcohol is used alongside drugs, sleeping pills, or certain medications, tell your treatment team honestly, because alcohol can increase risk and carries withdrawal symptoms that need to be monitored in people who drink heavily on a regular basis.

If we don’t know exactly what substances the patient is using, can treatment still start?

Yes, treatment can still begin. Families should share whatever they know — behavior changes, paraphernalia or substances found, when use happens, symptoms afterward, and treatment history. The treatment team will assess further from there. There’s no need to wait until the family knows the names of every substance.

Can someone using multiple substances stop them all at once at home?

This shouldn’t be decided based on the number of substances alone, because safety depends on what’s being used, how much, and whether physical dependence has developed. Anyone regularly using alcohol, benzodiazepines, or GHB/GBL in particular should have a risk assessment before stopping.

What medication is used to treat polysubstance use?

There is no single medication that treats every kind of substance addiction. A doctor needs to assess each substance involved, withdrawal symptoms, cravings, existing conditions, and any co-occurring psychiatric conditions, then choose the medication or care appropriate to each person’s situation.

Does polysubstance use always require going to a treatment center?

Not for everyone, but residential treatment may be appropriate when polysubstance use is ongoing, the person can’t stop on their own, there are withdrawal symptoms that need monitoring, relapse happens often, there’s a co-occurring psychiatric condition, or the person’s usual environment makes it easy to access substances.

Those with less complex symptoms who are suited to outpatient treatment can get an assessment at Piti Clinic, our mental health clinic located on Pradiphat Road near Saphan Khwai, Bangkok, to assess substance use, mental health, and plan treatment.

If it turns out the person needs to be separated from their triggers, needs structured care, or has more complex substance use and co-occurring conditions, residential treatment at Day One Rehabilitation Center in Nakhon Nayok province may be considered.

Polysubstance Use Can Be Treated — the More Complete the Assessment, the More Precise the Plan

Polysubstance use can make a family feel the problem is so complicated they don’t know where to start. But treatment doesn’t have to focus on just one substance. What matters is building a complete picture: what’s being used, why, how each substance is connected to the others, what withdrawal symptoms or co-occurring conditions exist, and what leads the person back to using.

Giving the treatment team honest information improves safety and makes for a much better-suited plan. Even if the person isn’t ready to stop everything, or hasn’t accepted that they have a problem, the family can still start by seeking counseling and finding ways to encourage an assessment.

The goal of treatment isn’t just to clear substances from the body — it’s to help the person understand their cycle of use, manage co-occurring conditions, handle cravings and triggers, and go back to living life without relying on one substance to counteract the effects of another.