Antipsychotic Medications

Antipsychotics are a class of psychotropic drugs used principally to treat psychotic symptoms such as hallucinations and delusions, and to manage conditions including schizophrenia and bipolar disorder. They are traditionally divided into first-generation (typical) and second-generation (atypical) agents, which differ in their receptor profiles and in their characteristic side-effect patterns.

Definition

Antipsychotic agents (neuroleptics) are drugs that reduce psychotic symptoms, primarily by antagonising or modulating dopamine D2 receptors, and are grouped into first-generation (typical) and second-generation (atypical) agents.

Scope

This entry covers what antipsychotics are, how they are classified, their main mechanism through dopamine and serotonin receptor activity, and the broad comparison of efficacy and tolerability across agents. It is a reference-educational topic for mental health nursing and describes how the class is understood in the literature rather than providing dosing or treatment instructions.

Key concepts

• First-generation (typical) antipsychotics
• Second-generation (atypical) antipsychotics
• Dopamine D2 receptor antagonism
• Serotonin 5-HT2A activity
• Extrapyramidal side effects
• Metabolic side effects
• Long-acting injectable formulations

Mechanisms

The shared mechanism of antipsychotics is reduction of dopaminergic neurotransmission, classically through blockade of dopamine D2 receptors; the dopamine hypothesis links this action to control of positive psychotic symptoms. First-generation agents block D2 strongly and are associated with prominent extrapyramidal effects, whereas second-generation agents combine D2 blockade with serotonin 5-HT2A antagonism and other receptor activity, shifting the side-effect profile toward metabolic effects. Comparative meta-analysis shows that individual agents differ substantially in both efficacy and tolerability, so the class is not pharmacologically uniform.

Clinical relevance

For nurses, antipsychotics are central to the care of people with psychotic and bipolar disorders, and knowledge of the class supports administration, observation for extrapyramidal and metabolic effects, monitoring of physical health, and education about adherence. Long-acting injectable formulations are one strategy described in the literature for supporting continuity of treatment. This content describes the class for reference and education and is not a basis for prescribing or individual treatment decisions.

Epidemiology

Antipsychotics are among the most studied psychotropic classes, with large pragmatic trials such as CATIE and network meta-analyses informing comparative understanding of their effects. Their metabolic and cardiometabolic adverse effects are a recognised contributor to physical morbidity among people with serious mental illness.

History

The first antipsychotic, chlorpromazine, was introduced in the early 1950s and revolutionised the treatment of schizophrenia. First-generation agents dominated until the introduction of clozapine and other second-generation drugs from the 1980s and 1990s, which were promoted for a lower burden of extrapyramidal effects but later recognised to carry metabolic risks; large comparative studies in the 2000s and 2010s refined the understanding of how individual agents differ.

Debates

Are second-generation antipsychotics clearly superior to first-generation agents?

Pragmatic trials such as CATIE and comparative meta-analyses found that the older distinction overstates a uniform advantage; agents differ individually in efficacy and tolerability, and the typical-versus-atypical dichotomy is an imperfect guide.

Key figures

• Jeffrey A. Lieberman
• Stefan Leucht
• Christoph U. Correll
• Stephen M. Stahl

Seminal works

• leucht-2013
• lieberman-2005

Frequently asked questions

What is the difference between typical and atypical antipsychotics?

First-generation (typical) antipsychotics block dopamine D2 receptors strongly and are more associated with extrapyramidal (movement) side effects, while second-generation (atypical) agents add serotonin and other receptor activity and tend to be more associated with metabolic side effects. Individual drugs within each group still differ.

What are antipsychotics used to treat?

They are used mainly for psychotic symptoms such as hallucinations and delusions, and for conditions including schizophrenia and bipolar disorder; some are also used as adjuncts in other situations. Specific use is an individual clinical matter beyond the scope of this reference entry.