Drugs used in Schizophrenia: A Literature Review
Lokhande Kranti Anant*, Prachi Kanawade, Sonone Sumit
Swastyadarpan Pratishthan’s, Shantiniketan College of Pharmacy, Dhotre Bk., Parner, Ahmednagar, MS., India.
*Corresponding Author E-mail: lokhandekranti1@gmail.com
ABSTRACT:
Schizophrenia is a severe mental illness that alters a person's way of thinking, feeling, and relating to the world, usually in a way that makes them appear to have lost contact with reality. This paper gives an overview of this intricate illness. We examine the three primary categories of symptoms: psychotic symptoms (such as hallucinations or delusions), negative symptoms (such as lack of motivation or emotion), and cognitive symptoms (which include difficulties in memory and attention). The review also briefly addresses the causes, with reference to genetics and brain structure, specifically imbalances in neurotransmitters such as dopamine. We discuss how clinicians come to diagnose the condition based on criteria from such guides as the DSM-5-TR and medical tests to exclude other problems. Treatment is the main emphasis, however. Schizophrenia treatment involves both medication and therapy. We outline the medications, with second-generation antipsychotics (SGAs) being the first-line treatment of choice because they produce fewer movement side effects than older medications, although they are associated with metabolic side effects. The review finishes outlining five specific antipsychotic medications—such as Clozapine, Risperidone, Haloperidol, describing how they act, what they are licensed to treat, and what the most common side effects are.
KEYWORDS: Schizophrenia, Antipsychotic drugs, Dopamine, DSM-5-TR, Clozapine.
Schizophrenia is a serious mental health condition that changes how a person thinks, feels, and acts1. Someone with schizophrenia might act or speak in a way that makes it seem like they are not connected to reality, which can be very upsetting for them and for those around them. Most people are diagnosed with schizophrenia during their teenage years or early adulthood, usually after their first experience with psychosis2.
Schizophrenia can make it hard for people to do normal daily things, and many face big problems with their health, social life, and money. Often, people with schizophrenia wait a long time before they get treatment, which can make their symptoms worse and affect their overall health and happiness over time.3
Signs and Symptoms of Schizophrenia:
Over time, changes in how a person thinks, feels, and interacts with others can happen before the first episode of psychosis4. The symptoms of schizophrenia can be different for each person, but they usually fall into three main groups: psychotic, negative, and cognitive5
· Psychotic symptoms: It affect how a person thinks, acts, and understands the world. These symptoms can make it hard for someone to tell what is real and what is not6.
· Negative symptoms: It involves losing interest in everyday activities, having less motivation, pulling away from others, and finding it hard to express emotions or function normally7.
· Cognitive symptoms: It often involve challenges with attention, concentration, and memory. These difficulties can make it hard to follow conversations, learn new information, or remember important appointments8.
Causes of schizophrenia:
Several factors can increase a person’s risk of developing schizophrenia
Genes: Schizophrenia can sometimes be passed down through families, but having a family member with the condition does not guarantee that others in the family will also develop it9. Research indicates that multiple genes may raise the likelihood of someone developing schizophrenia, but no single gene alone can cause the disorder10.
Brain structure and function: Research indicates that individuals with schizophrenia may exhibit slight variations in the size of specific brain regions and in the connections between different parts of the brain11. Neurotransmitter abnormalities are central to the pathophysiology of schizophrenia, with dopamine, serotonin, glutamate, and gamma-aminobutyric acid (GABA) all playing places. The link between dopamine and schizophrenia surfaced from the accidental discovery of dopamine D2 receptor blockers' effectiveness in easing psychotic symptoms12.
Family history: Family history of psychiatric illness, treatment and response to treatment, and history of suicidal or aggressive actions in natural cousins are noted. particular and social history13. The case’s language preferences, life circumstances, connections, children, employment history, artistic and societal views on psychiatric illness, stressors, trauma history, access to munitions, and legal enterprises are considered14.
Diagnosis:
The 2 systems used in diagnosing schizophrenia are, DSM-5-TR and ICD-10, which have slight variations.
1. DSM-5-TR: According to the DSM-5-TR, published by the American Psychiatric Association (APA) in 2023, the following are the individual criteria of schizophrenia: Two (or more) of the following, each present for a significant portion of time during 1 month (or less if successfully treated)15. At least one of these must be (1), (2), or (3). visions. Disorganised speech (e.g., frequent derailment or reason) Negative symptoms (i.e., lowered emotional expression or avolition) Significant functional decline in areas like work or connections must be observed to diagnose this complaint since symptom onset16. Nonstop signs must persist for at least 6 months, including at least 1 month of active-phase symptoms, which might be lower if treated. Symptoms can be prodromal or residual, including negative or downgraded active-phase symptoms15,17.
2. ICD-10: The case must parade at least one of the following for a period less than or equal to 1 month18. visions of control, influence, or passivity; delusional comprehensions Hallucinatory voices giving a running commentary on the case or agitating the case among themselves patient visions that are culturally unhappy or inconceivable Or at least 2 of the following symptoms must be observed for a period less than or equal to 1 month19.
EPIDEMIOLOGY:
The frequence of schizophrenia is between 0.6 and 1.9 in the U.S. population.10 also, a claims analysis has estimated that the periodic frequence of diagnosed schizophrenia in the U.S. is 5.1 per 1,000 lives20. The frequency of complaint seems to be equal in males and females, although the symptoms occurs at an earlier age in males than females21. Males tend to witness their first occasion of Schizophrenia in their early 20s whereas females generally witness their first occasion in their late 20s or early 30s 22.
Classification of Antipsychotic drugs:
1) Clozapine:
Clozapine is an atypical or second-generation antipsychotic drug used in treatment-resistant schizophrenia and to decrease suicide risk in schizophrenic patients.23
Structure :
IUPAC:8-chloro-11-(4-methylpiperazin-1-yl)-5H-dibenzo[b,e]diazepine
Molecular weight :326.823 g/mol
Molecular Formula: C18H19ClN4
Brand Names: Clozaril, Fazaclo, Versacloz
Generic Name : Clozapine
Mechanism of Action : Therapeutic efficacy of clozapine in schizophrenia is mediated through antagonism of the dopamine type 2 (D2) and the serotonin type 2A (5-HT2A) receptors.24
Indications : Clozapine is indicated for the treatment of severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment23,24. Because of the risks of severe neutropenia and of seizure associated with its use, Clozapine should be used only in patients who have failed to respond adequately to standard antipsychotic treatment.25
Side effects: sedation, hypersalivation, tachycardia, hypotension, hypertension, weight gain, constipation, urinary incontinence, and fever23-25
Clozapine was approved by the FDA in 1989 for treatment-resistant schizophrenia under the brand CLOZARIL. Due to its severe adverse effects profile, clozapine is only available through a restricted program under a Risk Evaluation Mitigation Strategy (REMS) called the Clozapine REMS Program.26,27
2) Chlorpromazine:
Chlorpromazine is a phenothiazine antipsychotic used to treat nausea, vomiting, preoperative anxiety, schizophrenia, bipolar disorder, and severe behavioral problems in children.28
Structure:
IUPAC: 3-(2-chlorophenothiazin-10-yl)-N, N-dimethylpropan-1-amine;hydrochloride
Molecular Weight: 318.9 g/mol
Molecular Formula: C17H19ClN2S
Brand names: Thorazine, Largactil.
Generic name: Chlorpromazine
Mechanism of Action: Chlorpromazine acts as an antagonist (blocking agent) on different postsysnaptic receptors -on dopaminergic-receptors (subtypes D1, D2, D3 and D4 - different antipsychotic properties on productive and unproductive symptoms), on serotonergic-receptors (5-HT1 and 5-HT2, with anxiolytic, antidepressive and antiaggressive properties28,29.
Indications: For the treatment of schizophrenia; to control symptoms nausea and vomiting; for relief of restlessness and apprehension before surgery; for acute intermittent porphyria; as an adjunct in the treatment of tetanus; to control30.
Side effects: Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat Infection—fever, chills, cough, or sore throat, High fever, stiff muscles, increased sweating, fast or irregular heartbeat, and confusion, which may be signs of neuroleptic malignant syndrome28,31
3) Haloperidol:
Haloperidol is an antipsychotic agent used to treat schizophrenia and other psychoses, as well as symptoms of agitation, irritability, and delirium.32
Structure:
IUPAC: 4-[4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl]-1-(4-fluorophenyl)butan-1-one
Molecular weight: 375.9 g/mol
Molecular Formula: C21H23ClFNO2.
Brand Names: Haldol
Generic Name: Haloperidol
Mechanism of Action: It exerts its antipsychotic effect through its strong antagonism of the dopamine receptor (mainly D2), particularly within the mesolimbic and mesocortical systems of the brain.33
Indications: Haloperidol is indicated for a number of conditions including for the treatment of schizophrenia, for the manifestations of psychotic disorders, for the control of tics and vocal utterances of Tourette’s Disorder in children and adults, for treatment of severe behavior problems in children of combative, explosive hyperexcitability (which cannot be accounted for by immediate provocation).34
Side effects: Common side effects include movement problems, sleepiness, dry mouth, low blood pressure upon standing, and increased weight.32,35 Serious side effects may include the potentially permanent movement disorder tardive dyskinesia, neuroleptic malignant syndrome, severe lowering of the seizure threshold, and low white blood cell levels.36.
4) Perphenazine:
Perphenazine is a phenothiazine used to treat schizophrenia as well as nausea and vomiting.37
Structure:
IUPAC: 2-[4-[3-(2-chlorophenothiazin-10-yl)propyl]piperazin-1-yl]ethanol
Molecular Weight : 404.0 g/mol
Molecular Formula :C21H26ClN3OS
Brand names : Trilafon.
Generic name: Perphenazine
Mechanism of Action: Binds to the dopamine D1 and dopamine D2 receptors and inhibits their activity.38
Indications: For use in the management of the manifestations of psychotic disorders and for the control of severe nausea and vomiting in adults.39
Side effects: Extrapyramidal reactions (e.g., Parkinson-like symptoms, dystonia, akathisia, tardive dyskinesia), drowsiness, muscular weakness, dry mouth, blurred vision, weight gain, skin reactions, amenorrhea, galactorrhea.37-39
5) Risperidone:
Risperidone is a second-generation antipsychotic medication used to treat a number of mental health disorders including schizophrenia, bipolar mania, psychosis, or as an adjunct in severe depression.40
Structure:
IUPAC: 3-[2-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]ethyl]-2-methyl-6,7,8,9-tetrahydropyrido[1,2-a]pyrimidin-4-one
Molecular weight: 410.49
Molecular formula: C₂₃H₂₇FN₄O₂.
Brand name: Risperdal , Risperdal Consta
Generic name : Risperdal
Mechanism of action:
Risperidone inhibit the D2 dopaminergic receptors and 5-HT2A serotonergic receptors in the brain. D2 dopaminergic receptors are transiently inhibited by risperidone, reducing dopaminergic neurotransmission, therefore decreasing positive symptoms of schizophrenia, such as delusions and hallucinations.40,41
Indications: Schizophrenia, Aggresive behaviour, Attention deficit hyperactivity disorder (ADHD), Autism, Bipolar disorder.42
Side effects: Common side effects of risperidone: Headaches, Putting on weight or changes in appetite, Stomach pain, Feeling or being sick (nausea or vomiting)Constipation, Diarrhoea.41,42
Serious side effects: twitching or jerking movements, swelling, pain and redness in your leg, stiff muscles, difficulty to move or control muscles, dyskinesia43
Conclusion:
Schizophrenia is a severe and complicated mental disorder that impacts a person's thoughts, emotions, and capacity to interact with reality. As has been demonstrated in this review, the condition encompasses a combination of psychotic, negative, and cognitive symptoms, and such may become real challenges for one's ability to cope with daily life. Although the precise causes remain under investigation, they constitute a combination of genetics and neurochemistry, particularly involving the neurotransmitter dopamine.
Treatment is important, and the bulk of the basis for the treatment of schizophrenia lies in the pharmacological approach—medication. The aim is to control symptoms, avoid relapse, and enable the individual to lead a more functional lifestyle. Physicians will usually begin with second-generation antipsychotics (SGAs) such as Risperidone or Aripiprazole since they cause fewer severe movement side effects compared to the older, first-generation medications. These new medications, however, can also have their own set of complications, including metabolic problems such as weight gain.
The selection of the appropriate medication is an important part of treating patients with schizophrenia and enhancing their quality of life.
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Received on 05.12.2025 Revised on 12.01.2026 Accepted on 10.02.2026 Published on 10.04.2026 Available online from April 13, 2026 Asian J. Res. Pharm. Sci. 2026; 16(2):186-190. DOI: 10.52711/2231-5659.2026.00029 ©Asian Pharma Press All Right Reserved
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