Antipsychotics

Antipsychotic medications are the primary pharmacological treatment for psychosis — the class of drugs specifically designed to reduce hallucinations, delusions, and disorganized thinking. They're used across a range of conditions where psychosis appears, including schizophrenia, schizoaffective disorder, bipolar disorder, psychotic depression, and psychosis caused by other medical or substance-related factors.

Antipsychotics typically need to be continued over time to maintain their effect, similar to how medications for other chronic conditions (like high blood pressure) work.

How They Work

Most antipsychotics work primarily by blocking dopamine receptors in the brain, particularly in pathways associated with psychotic symptoms. The leading theory behind psychosis (though understanding continues to evolve) involves overactive dopamine signaling in certain brain circuits, and reducing that signaling tends to reduce hallucinations and delusions.

Many newer antipsychotics also affect serotonin receptors, which is thought to contribute to their somewhat different side-effect profile compared to older medications, and may help with mood and negative symptoms in some cases, though effects here are generally more modest than the effect on positive symptoms.

Two Broad Classes

First-Generation ("Typical") Antipsychotics

These were the first antipsychotics developed, starting in the 1950s. Examples include:

  • Haloperidol

  • Chlorpromazine

  • Fluphenazine

  • Perphenazine

Strengths: Effective at reducing positive symptoms (hallucinations, delusions); some are available in long-acting injectable form; generally less expensive.

Drawbacks: Higher risk of extrapyramidal side effects — movement-related problems including:

  • Tremor and muscle stiffness (parkinsonism)

  • Akathisia (an intense inner restlessness, often distressing)

  • Acute dystonia (sudden, sometimes painful muscle spasms)

  • Tardive dyskinesia — involuntary, repetitive movements (often of the face or mouth) that can develop after long-term use and, in some cases, persist even after stopping the medication

Second-Generation ("Atypical") Antipsychotics

Developed starting in the 1990s and generally preferred today as first-line treatment. Examples include:

  • Risperidone

  • Olanzapine

  • Quetiapine

  • Aripiprazole

  • Ziprasidone

  • Lurasidone

  • Paliperidone

  • Clozapine (technically second-generation, but typically discussed separately — see below)

Strengths: Lower risk of movement-related side effects compared to first-generation drugs; some are also approved for treating mood symptoms (bipolar depression or mania), giving them a broader role.

Drawbacks: Higher risk of metabolic side effects, including weight gain, elevated blood sugar (increasing diabetes risk), and unfavorable changes in cholesterol — the degree varies significantly by specific medication (olanzapine and clozapine tend to carry more metabolic risk; aripiprazole and lurasidone tend to carry less).

Clozapine: A Special Case

Clozapine deserves its own discussion because it's uniquely effective — and uniquely risky.

  • It's considered the most effective antipsychotic for treatment-resistant psychosis, generally defined as insufficient improvement after trying at least two other antipsychotics at adequate doses.

  • It carries a risk of agranulocytosis, a serious and potentially life-threatening drop in white blood cell count, which requires regular blood testing (frequently at first, then less often over time) for as long as someone takes it.

  • Because of the monitoring burden and other side effects (including sedation, weight gain, and, rarely, effects on heart function), it's typically reserved for people who haven't responded well to other options — but for those people, it can be markedly more effective than switching between other antipsychotics.

Long-Acting Injectable (LAI) Antipsychotics

Several antipsychotics — including some first- and second-generation options — are available as long-acting injections, given every 2 to 12 weeks depending on the specific medication. These can be helpful for:

  • People who have difficulty taking a daily pill consistently

  • Reducing the risk of relapse tied to missed doses

  • Some people, avoiding the daily reminder of illness that a pill can represent

They're not right for everyone, and starting one usually still involves first confirming that the oral form of the same medication is well tolerated.

Common Side Effects Across Antipsychotics

While specifics vary by medication, general categories of side effects include:

  • Sedation — drowsiness, particularly common with quetiapine, olanzapine, and clozapine

  • Weight gain and metabolic changes — appetite increase, weight gain, and effects on blood sugar and cholesterol

  • Movement-related effects — more common with first-generation antipsychotics but possible with some second-generation ones too, especially at higher doses

  • Hormonal effects — some antipsychotics (notably risperidone and paliperidone) can raise prolactin levels, potentially causing menstrual changes, sexual side effects, or breast tissue changes

  • Anticholinergic effects — dry mouth, constipation, blurred vision (more common with certain medications like olanzapine and clozapine)

  • Cardiac effects — some antipsychotics can affect heart rhythm (QT interval prolongation), which is why baseline and follow-up EKGs are sometimes recommended, especially at higher doses or when combined with other QT-prolonging medications

  • Sexual side effects — can occur with several antipsychotics, sometimes contributing to reluctance to continue treatment if not addressed

Because side-effect profiles differ so much between individual medications — not just between the two broad classes — choosing an antipsychotic often involves weighing a specific person's risk factors (metabolic health, cardiac history, sensitivity to sedation, prior response) against the profile of each option.

How They're Used in Practice

Acute treatment — during an active psychotic episode, antipsychotics are typically started and adjusted somewhat quickly to reduce distressing symptoms, sometimes in a hospital setting for closer monitoring.

Maintenance treatment — once symptoms improve, treatment generally continues at a stable dose to prevent relapse. Stopping antipsychotic medication — even after symptoms resolve — is associated with a significantly higher risk of relapse, which is why long-term treatment is usually recommended for chronic or recurrent psychotic conditions.

Combination with other medications — depending on the underlying diagnosis, antipsychotics are often used alongside mood stabilizers (for bipolar disorder), antidepressants (for psychotic depression), or, for treatment-resistant cases, in combination with each other, though this last approach carries more side-effect risk and less evidence than single-medication treatment.

Finding the Right Medication

Because response and side effects vary significantly between individuals — and can't be reliably predicted in advance — finding the right antipsychotic is often a process of trial and adjustment, guided by a psychiatrist. Relevant factors include:

  • Prior response (personal or family) to specific medications

  • Tolerability of side effects, particularly sedation, weight gain, or movement effects

  • Other health conditions (diabetes, heart disease, and others) that might make certain medications riskier

  • Whether an oral or long-acting injectable form fits better with the person's life and preferences

  • Cost and insurance coverage, which can meaningfully affect what's realistically accessible

The Role of Medication Within Broader Treatment

Antipsychotics are highly effective at reducing positive symptoms (hallucinations, delusions, disorganized thinking) but are generally less effective for negative symptoms (flattened emotion, reduced motivation, social withdrawal) and cognitive symptoms (attention, memory, planning difficulties). Because of this, medication is usually most effective when combined with psychosocial treatments — therapy, family support, social skills training, and supported employment or education — rather than relied on as a standalone solution.

Stopping or Changing Medication

Any change to antipsychotic treatment — starting, stopping, switching, or adjusting dose — should be done under the guidance of a prescribing psychiatrist. Stopping abruptly, without medical supervision, carries meaningful risks:

  • A significantly elevated chance of relapse, sometimes more severe than the original episode

  • In some cases, withdrawal-related symptoms

  • Loss of the gradual tapering process that helps identify the lowest effective dose or confirm whether ongoing medication is truly still needed

For some people, especially after a single, clearly triggered episode, a psychiatrist may eventually consider a carefully monitored taper. For others, particularly those with a chronic or recurrent condition, long-term maintenance treatment is generally recommended.