Medication resource centre


What are Antipsychotic Medications?

Antipsychotic medications are an important part of the treatment plan for people living with schizophrenia and other psychotic illnesses. They are used to treat symptoms and help improve quality of life. Schizophrenia can have many different symptoms. Antipsychotic medications work best on the positive symptoms of schizophrenia such as hallucinations, disorganized thinking, paranoia and delusions. Some individuals also experience negative symptoms, such as lack of motivation and low mood. Antipsychotics may help improve these symptoms for some individuals, however they may not eliminate them completely. It is important to understand what symptoms the antipsychotic medication will help so you can monitor your response. 
Antipsychotics can also be used to treat other conditions such as major depression and bipolar disorder. It is important to discuss with your doctor and pharmacist the reason why you are taking antipsychotic medication.
Antipsychotics can control many symptoms of schizophrenia and other mental illnesses but they cannot cure the illnesses. These medications help reduce symptoms so that you can feel better, but they may not eliminate the symptoms completely. Antipsychotic medications work best when taken regularly, even when you start to feel better.
It is important to know that all antipsychotic medications have two names. The first name is the brand name.  This is the original name given to the medication by the pharmaceutical company that discovered the medication. The second name is the chemical name of the medication. This name represents the active ingredient in the medication. The chemical name should not be confused with “generic” brand medications, which are medications that are copies of the brand name medications made by different companies and sold for lower prices. The chemical name of a medication stays the same for brand and generic brand medications.
Example: Zyprexa (olanzapine); Apo-Olanzapine (olanzapine)
  • In the above example, Zyprexa is the brand name of an antipsychotic discovered by the pharmaceutical company Eli Lilly.
  • The generic or chemical name of the medication is olanzapine, which is the active ingredient in the medication.
  • Apo-Olanzapine is the name of an antipsychotic medication produced by the generic pharmaceutical company Apotex. In this case, the chemical name is still olanzapine as that is the active ingredient.

Brand-Name and Generic Antipsychotic Medications

Generic medications are essentially copies of brand name medications. They have similar active ingredients, dosages, side effects and intended uses as the brand name medications. Sometimes generic medications have different colours, flavours, shapes or combinations of inactive ingredients compared to the brand name medication; however, the main ingredients responsible for the effect are the exact same. The only reason the generic medications are sold for less is because the generic medication manufacturers did not have the expenses of developing and marketing the new medication. Just like brand name medications, all generic medications go through a rigorous approval process by Health Canada to ensure their quality and safety.


Label and Off-Label Use

All medications that are approved for sale in Canada have been approved by Health Canada to be used for a specific medical illness. This is called “label indication”.  This means that the medication was studied and shown to be beneficial for a particular illness.  
Sometimes, prescribers use medications to treat illnesses and/or populations for which the medication was not originally studied. This use of the medication is called “off-label”.  Off-label use of medication does not mean there is no evidence for the medications. In most cases there is research to support the use of medications for illnesses and/or populations that were not originally studied.  
Off-label use of medication is quite common in psychiatry. For example, the use of antipsychotics to treat behavioural issues associated with moderate to severe Alzheimer’s Disease is considered “off-label” use of antipsychotics. Another example of off-label use is the use of the antipsychotic quetiapine for insomnia or difficulties sleeping. The use of most antipsychotic medications in children and adolescents is off-label as well because the original studies for these medications were not done with children or adolescents.  
It is important to understand why your doctor is prescribing a certain medication for you and which symptoms the medication is going to address. You should discuss with your doctor the risks and benefits of the prescribed medication for your illness, age, etc.  

History and Different Types of Antipsychotic Medications [1]

First-Generation of Antipsychotics: The "Typicals"

In 1950, the first antipsychotic medication, chlorpromazine, was developed. It was originally used to increase the effects of anesthesia in people undergoing surgery. Because of its calming effect, psychiatrists began using it to treat psychosis. 

Chlorpromazine was marketed under the name Largactil® in 1952 and Thorazine® in 1954. Access to this medication was a major breakthrough in the treatment of mental illnesses. Prior to the development of this medication many individuals with mental illnesses lived in hospitals. One reason for this is because the symptoms experienced by individuals were significant and impacted their ability to live independently in the community. The introduction of chlorpromazine was crucial as it showed society that the symptoms of mental illnesses could be treated successfully and individuals could live productive lives in the community.

By the early 1970s, chlorpromazine was the most widely used antipsychotic medication, with many other similar medications available. Early on in their use, doctors noticed that these first-generation antipsychotic medications frequently caused movement-related side effects, also called extrapyramidal symptoms.

Second-Generation of Antipsychotics: The "Atypicals"

Clozapine was the first antipsychotic medication developed that caused fewer movement-related side effects (extrapyramidal symptoms). This was a significant discovery. Prior to this it was believed that for an antipsychotic medication to treat symptoms of schizophrenia, it must cause movement side effects. Clozapine showed that this theory was false, as it was very effective. Because of this difference in side effects, Clozapine became the first atypical antipsychotic. Clozapine was initially developed in the 1960s, and inspired the discovery of several other atypical antipsychotics. Atypical antipsychotic medication is like Clozapine in that they cause less movement side effects compared to the typical medications.

Third-Generation of Antipsychotics: Also "Atypicals"

In addition to second generation antipsychotics there is also a category known as third generation antipsychotics which are also part of the atypical group. The distinction between second- and third-generation antipsychotics is based on mechanistic differences. Specifically, the third generation agents are defined as partial dopamine agonists, where as second generation agents are considered dopamine antagonists. This means that the third generation antipsychotics prevent excess dopamine from overstimulating receptors in certain parts of the brain and prevents areas of deficient dopamine from understimulating receptors. Theoretically this mechanism should enhance efficacy and minimize side effects, particularly EPS. Aripiprazole was the first approved antipsychotic that is a partial dopamine agonist, but we now also have brexipiprazole in this class as well.  

Medications Today

Since the introduction of chlorpromazine, many other typical and atypical antipsychotic medications have been developed. The main difference between typical and atypical antipsychotics is that the atypicals have milder movement-related side effects compared to the typicals. While both categories of medications work well, no single medication works well for everyone who takes it. In some cases, someone may have to try several medications before finding the one that works best for them.
While antipsychotics are the main class of medications used to treat schizophrenia and other psychotic illnesses, there are other types of medications that may also be used to treat specific symptoms such as depression, anxiety, or insomnia.

How Do Antipsychotic Medications Work?

Our brains have billions of nerve cells that communicate with each other through nerve endings. These messages are transmitted by chemicals called neurotransmitters. In schizophrenia, it is thought that something goes wrong with this complex communication system.
Antipsychotics work by helping to rebalance the communication system. Typical antipsychotics work mostly by blocking the action of the neurotransmitter dopamine. Atypical antipsychotics also block dopamine, along with other neurotransmitters such as serotonin and noradrenaline.
While there are similarities between medications within each group of antipsychotics, it is important to understand that each individual medication is different. Each medication will affect everyone differently. What works for one person may not work for you. It is important to discuss your response to your medication with your doctor. It can take several weeks for antipsychotic medications to have an effect. It is important to be patient during the first 4 - 8 weeks of treatment as it takes time to see improvements. In some cases, medications may work for several months to years and then stop working. It is not uncommon to have changes in medications over the course of your illness. 
[1] Shen, W. (1999). A history of antipsychotic drug development. Comprehensive Psychiatry, 40(6), 407-414.