Central nervous system depression is when your brain and nervous system slow down. It occurs after using a CNS depressant drug, such as opioids or benzodiazepines.

Depression of the central nervous system (CNS) typically occurs when a person uses a substance that is designed to slow down your brain and relax your muscles, leaving you with a feeling of calm. These substances are known as CNS depressants.

If you have anxiety or a sleep disorder your doctor may prescribe you a CNS depressant, such as a sedative, to help relieve your symptoms.

If these substances are misused or are taken recreationally, they can become addictive as well as cause excessive CNS depression. This can become dangerous and lead to slow breathing, unconsciousness, coma, or even death.

Treatment for excessive CNS depression is available and varies depending on the cause.

The central nervous system is made up of the brain and spinal cord, which control most bodily functions, including breathing and the heart. CNS depression occurs when a person’s central nervous system has slowed down, causing a slower heart rate and slower breathing.

CNS depressant medications work to depress the central nervous system, which slows down brain activity and causes your muscles to relax. This makes the drugs effective. It only becomes a problem when the medications are taken in excess, resulting in excessive central nervous system depression.

Many CNS depressants work by increasing the activity of a neurotransmitter in your brain called gamma-aminobutyric acid (GABA). This slows down the delivery of messages between cells, producing a drowsy or calming effect. This makes CNS depressants useful in treating:

Some common examples of CNS depressants include:

  • sedatives
  • tranquilizers
  • hypnotics

CNS depression can be diagnosed by a doctor. If someone has been on medication for a while or misused it, a doctor may look at their medical history and conduct tests to determine whether CNS depression is an accurate diagnosis.

Some common, mild symptoms of CNS depression may include:

  • drowsiness
  • feeling uncoordinated
  • dizziness
  • slurred speech
  • lightheadedness
  • dry mouth
  • poor concentration

Usually, these symptoms are helpful in managing anxiety and sleep conditions and shouldn’t cause alarm. If they’re interfering with your daily life, consider talking about them with your doctor. They may recommend that you switch medications or adjust the dosage.

Symptoms of severe CNS depression include:

  • low blood pressure
  • slowed breathing
  • memory loss
  • confusion
  • difficulty with movement

If someone has any severe symptoms, they should seek immediate medical care. Severe symptoms can lead to coma, respiratory suppression, and death.

The most common medications that cause CNS depression include:


Benzodiazepines like diazepam and clonazepam are used to treat anxiety and panic attacks. Benzodiazepines are not prescribed for long-term use because of their high risk of developing dependence or addiction.


Opioids are medications that help reduce the intensity of pain. When properly managed, short-term use of opioids can be effective. Long-term or recreational use can lead to dependence and addiction. Opioid misuse is a leading cause of CNS depression.

Common opioids include:

  • oxycodone (OxyContin, Roxicodone)
  • hydrocodone (Vicodin, Norco)
  • morphine (Duramorph, MS Contin)
  • codeine (Tuzistra SR)
  • oxymorphone (Opana)
  • fentanyl (Duragesic, Subsys)

Sleep medication

Sleep medications like Ambien work by slowing down brain activity, which makes them a good choice if you have a sleep disorder. They have fewer side effects and less risk of dependence than other CNS depressants.


Barbiturates are typically prescribed to reduce anxiety and treat sleep disorders. However, because of their high risk of overdose, doctors use them less frequently for those conditions and more frequently to treat seizure disorders or in surgical procedures.

Treatment for CNS depression depends on which drug caused the symptoms. Medications that are used as an antidote to reverse the effects of some CNS drugs include:

  • Naloxone: Naloxone can rapidly reverse an opioid overdose and can quickly return slowed or stopped breathing back to normal. It comes in a nasal spray known as Narcan or as an injectable that can be administrated in the vein or skin.
  • Flumazenil: This medication has been shown to effectively treat a benzodiazepine overdose. Since it can’t completely reverse slowed breathing and because it’s short-acting, a doctor may administer it several times every 20 minutes.

Treatment for barbiturates and nonbenzodiazepines includes monitoring the following until the drug is eliminated from the person’s system:

  • body temperature
  • pulse
  • breathing
  • blood pressure

Treatment for substance use disorder (SUD) involving CNS depressants involves drug detox and psychotherapy, such as cognitive-behavioral therapy (CBT). This can either be an inpatient or outpatient program.

Alcoholics Anonymous and Narcotics Anonymous, 12-step programs that foster social support, may be a helpful addition to treatment.

Doctors may also prescribe short- or long-term medication to help support opioid use disorder recovery. These medications include:

  • buprenorphine
  • buprenorphine/naloxone (Suboxone)
  • methadone

Excessive CNS depression is when the central nervous system slows down to notable or even dangerous levels. Harmful levels of CNS depression are caused by the misuse of CNS depressants, which are drugs used to treat conditions like anxiety and sleep disorders.

People who take CNS depressants may have mild symptoms such as drowsiness or feeling uncoordinated. People who misuse the medication or become dependent on it may have more severe symptoms, such as very slow breathing and memory loss.

Treatment for SUD is available through counseling and supportive medications.

If you or someone you know is misusing CNS depressants, help is available. You can contact your doctor or speak with a counselor to gain support through treatment.