Antipsychotic drugs: what they are, how they treat psychosis

By Cristiano Antonino On Apr 13, 2023

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Antipsychotic drugs treat psychosis, a collection of symptoms that affect your ability to tell what is real and what is not

These drugs are a fundamental part of the treatment of conditions involving psychosis.

Without them, many of these conditions are so disruptive or severe that they require 24/7 psychiatric care.

What are antipsychotics?

Antipsychotic drugs are medications that mainly treat conditions and symptoms related to psychosis.

But taking an antipsychotic drug does not always mean that you have a symptom or condition related to psychosis.

This is because these drugs are also very important for the treatment of other conditions.

What is psychosis?

Psychosis is not a medical condition.

It is a collection of symptoms that indicate that your brain is not processing certain types of information as it should.

All symptoms involve a disconnection from reality. The main symptoms are hallucinations and delusions.

It can also involve disorganised thoughts and actions or dulling the way you show emotions.

Are there different types of antipsychotic drugs?

There are two main types of antipsychotic drugs:

First-generation antipsychotics. Also known as ‘typical antipsychotics’, these were the first types of drugs developed for the treatment of psychosis. Most are not commonly used to treat psychosis now.
Second-generation antipsychotics. Also known as ‘atypical antipsychotics’, these are now the main drugs for the treatment of psychosis. This is mainly due to the fact that they have fewer side effects.

List of antipsychotic drugs

First-generation (typical) antipsychotics

Chlorpromazine (Thorazine*).
Fluphenazine (Prolixin*, Permitil*).
Haloperidol (Haldol®).
Loxapine (Adusuve®, Loxitane*).
Molindone (Moban*).
Perphenazine (Trilafon*).
Pimozide (Orap*).
Prochlorperazine (Compazine®*, Compro®).
Thiotixene (Navane*).
Thoridazine (Mellaril*).
Trifluoperazine (Stelazine*).

Second-generation (atypical) antipsychotics

Aripiprazole (Abilify®, Aristada®).
Asenapine (Secuado®, Saphris®).
Brexpiprazole (Rexulti®).
Cariprazine (Vraylar®).
Clozapine (Clozaril®, Versacloz®, Fazaclo*).
Iloperidone (Fanapt®).
Lumateperone (Caplyta®).
Lurasidone (Latuda®).
Olanzapine (Zyprexa®, Lybalvi®, Symbyax®).
Quetiapine (Seroquel®).
Paliperidone (Invega®).
Pimavanserin (Nuplazid®).
Risperidone (Perseris®, Risperdal®).
Ziprasidone (Geodon®).

How do antipsychotics work?

All antipsychotics work by changing the way the brain uses certain signals known as neurotransmitters.

Cells throughout the nervous system have receptors, which are like locks, on their surface.

Neurotransmitters are like keys and have very specific shapes.

If a neurotransmitter with the right shape attaches to a receptor, it can activate the cell and tell it to do something.

Some neurotransmitters have almost the right shape, but they do not activate the cell.

Instead, they block neurotransmitters that could activate the cell.

Antipsychotic drugs rely on the lock-and-key system for neurotransmitters and receptors in different ways:

First-generation antipsychotics: they block the way the brain uses several neurotransmitters, in particular dopamine. They also block acetylcholine (pronounced ‘Uh-SEE-till-CO-lean’), histamine and norepinephrine from attaching to various receptors.
Second-generation antipsychotics: these block certain dopamine and serotonin receptors. But unlike first-generation antipsychotics, these drugs do not only block receptors. They also activate certain other dopamine and serotonin receptors. Blocking some receptors and activating others is why these drugs work differently.

What conditions do antipsychotics treat?

Antipsychotics treat conditions that cause or involve psychosis.

These include:

Schizophrenia (and its spectrum of disorders, including schizoaffective disorder and schizophreniform disorder).
Bipolar disorder.
Mania.
Major depressive disorder with psychotic features.
Delusional disorder.
Severe agitation.
Borderline personality disorder.
Dementia.
Delirium.
Substance-induced psychotic disorder.

Providers may treat other conditions with antipsychotics, but those drugs are not their main treatment.

These conditions include:

Tourette’s syndrome.
Huntington’s disease.
Parkinson’s disease.
Lesch-Nyhan syndrome.
Obsessive-compulsive disorder.

What are the potential benefits of antipsychotic drugs?

Antipsychotic drugs have several benefits, including:

Range of conditions they treat. Antipsychotics can treat specific brain conditions. They can also treat mental health conditions (many of which occur for brain-related reasons that are not fully understood).
Type of conditions they treat. Antipsychotics treat conditions that can be very complex, disruptive and severe. Some of these conditions are very difficult (if not impossible) to treat with other types of drugs. Moreover, many people with these conditions would need long-term (or even lifelong) 24/7 care without these drugs.
History of research and use First-generation antipsychotics came into use in the early 1950s. The first second-generation antipsychotics came into use in the 1960s. This means that these drugs have decades of research and study behind them.
Number of drugs available. There are many different types of antipsychotic drugs. This means that your doctor may often offer you options to choose from when recommending a drug.
Contributions to other therapeutic approaches. Antipsychotics can also make other types of mental health treatment more effective. When used together, antipsychotics and mental health therapy (the technical term is ‘psychotherapy’) are usually more likely to help a person.

What are the possible disadvantages, side effects and complications of antipsychotics?

Antipsychotics are useful, but there are possible disadvantages.

Antipsychotic drugs can have various side effects and complications, including:

Drug-induced movement disorders. First- and second-generation antipsychotics may cause an inability to sit still (akathisia) or uncontrolled movements of facial muscles (tardive dyskinesia). Other symptoms include tremors or Parkinsonism-like symptoms. They can also cause neuroleptic malignant syndrome, a potentially fatal complication. Scientists have developed second-generation antipsychotics to avoid this side effect.
Heart and circulatory problems. Antipsychotic drugs can alter heart rhythm. They can also cause orthostatic hypotension, which is a drop in blood pressure when you stand or sit up quickly that can make you fall or faint.
Interactions. Antipsychotic drugs can interact with many other types of medication. Be sure to tell your doctor about any medication, supplement, vitamin or herbal remedy you take. This can help them determine if there is a risk of interactions with an antipsychotic drug they prescribe.
Effects on metabolism. Antipsychotic drugs can cause high cholesterol (hyperlipidaemia) and high blood sugar (hyperglycaemia). They can also increase the risk of developing type 2 diabetes.
Dizziness and sedation. All antipsychotics can have a sedative effect, in the sense that they make you tired. They can also cause dizziness, increasing the risk of falls and injuries.
High prolactin levels (hyperprolactinemia). Antipsychotics can affect prolactin hormone levels. This can affect fertility and cause missed menstruation (amenorrhoea) and loss of breast discharge when not breastfeeding/breastfeeding (galactorrhoea) in women and persons assigned to the female at birth. It may cause infertility and sexual dysfunction in men and persons assigned male at birth.
Immune disruption. Some antipsychotics may cause agranulocytosis, a dangerous condition involving a weakened immune system.
Jaundice. This is when the skin and the whites of the eyes (sclera) turn yellow due to a liver problem.

Other less serious side effects may include:

Weight gain.
Dry mouth.
Constipation.
Urinary retention.

How long can I stay on antipsychotics?

Some antipsychotic drugs are only for short-term use.

Others, you can take them for years or even indefinitely.

This can vary depending on the drug you take, why you take it, other conditions you have or medications you take, side effects you experience or want to avoid, and more.

Your doctor is the best person to tell you what he or she recommends when it comes to how long you take one of these drugs.

Can I work or drive if I am taking antipsychotic drugs?

Some antipsychotic drugs can make you feel tired or sleepy.

You should talk to your doctor about whether or not you can drive after taking one of these drugs.

They can tell you when it is safe to drive and what you can do to minimise any side effects that might affect your driving.

What are the reasons why I cannot take antipsychotics?

Several conditions can worsen if you take antipsychotics.

Fortunately, there are many different antipsychotic drugs, so your doctor can probably recommend one that has little or no risk of worsening another medical problem you have.

If you have any of the following conditions, it is important to inform your doctor:

Liver damage or disease (cirrhosis).
Heart disease.
A history of stroke or circulatory problems in the brain (cerebrovascular disease).
Parkinsonism (including Parkinson’s disease and many conditions that cause similar symptoms).
Bone marrow or immune problems.
Very high (hypertension) or low blood pressure (hypotension).
Type 2 diabetes.
Glaucoma.
Enlarged prostate (benign prostatic hyperplasia).
Stomach ulcer.
Chronic respiratory conditions.

When should I call my doctor?

Antipsychotics can cause serious side effects or complications for some people.

Your doctor can tell you what symptoms to look out for and what you should do if you notice them.

In general, you should call your doctor as soon as possible if you notice any of the following symptoms:

Agitation or tremors.
Uncontrolled movements of the face.
Yellowing of the skin or whites of the eyes.
Symptoms of neuroleptic malignant syndrome, including high fever, stiff or rigid muscles, confusion or unusual/unexpected changes in mental state.

If you suspect that someone may be trying to harm yourself or someone else

Antipsychotics treat mental health conditions that can greatly increase the risk of self-harm, suicidal thoughts and behaviour or violent behaviour towards others.

You should get immediate help if you think you are hurting yourself or others, or if you suspect that someone you know is in danger of trying to hurt themselves or others.

What is the best antipsychotic drug or what is the safest antipsychotic drugs?

There is no single answer to these questions.

This is because the best or safest antipsychotic drug for you might be different from the best drug for someone else, even someone else with the same condition.

What is the most commonly prescribed antipsychotic drug?

The most commonly prescribed first-generation antipsychotic drugs are:

Haloperidol.
Perphenazine.

The most commonly prescribed second-generation antipsychotic drugs are:

Ziprasidone.
Olanzapine.
Quetiapine.
Risperidone.

Antipsychotics are a key drug for the treatment of psychosis, a set of symptoms that affect your understanding of what is real and what is not.

Symptoms of psychosis can occur with many conditions and these conditions can be extremely severe and disruptive.

Antipsychotics offer a treatment option that can help people who would otherwise need mental health care in hospital.

This means that antipsychotics can help people suffering from psychosis-related conditions to return to their homes, lives and routines.

Range of conditions they treat Antipsychotics can treat specific brain conditions. They can also treat mental health conditions (many of which occur for brain-related reasons that are not fully understood).

Type of conditions they treat. Antipsychotics treat conditions that can be very complex, disruptive and severe. Some of these conditions are very difficult (if not impossible) to treat with other types of drugs. Moreover, many people with these conditions would need long-term (or even lifelong) 24/7 care without these drugs.

History of research and use First-generation antipsychotics came into use in the early 1950s. The first second-generation antipsychotics came into use in the 1960s. This means that these drugs have decades of research and study behind them.

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Number of drugs available. There are many different types of antipsychotic drugs. This means that your doctor can often offer you options to choose from when recommending a drug.

Contributions to other therapeutic approaches. Antipsychotics can also make other types of mental health treatment more effective. When used together, antipsychotics and mental health therapy (the technical term is ‘psychotherapy’) are usually more likely to help a person.

Bibliographic references

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Willner K, Vasan S, Abdijadid S. Atypical Antipsychotic Agents. (https://www.ncbi.nlm.nih.gov/books/NBK448156/) [Updated 2022 Nov 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Accessed 2/12/2023.