Olanzapine vs. Risperidone: Which Antipsychotic is Right for You?

By Team TherapyRoute

If you or someone close to you has been offered olanzapine or risperidone, you likely want one answer. Which one is right for you?

The honest reply is that neither is simply better. Both are second-generation antipsychotics, medicines used for conditions like schizophrenia and bipolar disorder. The choice usually turns on which side-effect pattern suits your body and your life.

This page covers the side-effect differences readers ask about most often: metabolic load, prolactin, and movement effects. A prescriber weighs more than these, including how sedating a medicine is, how you have responded to medicines before, which formulations are available, and any plans for pregnancy or breastfeeding. That weighing is theirs to do with you.

The trade-off that drives the choice

Olanzapine and metabolic load

Metabolic load means effects on weight, blood sugar and cholesterol. Olanzapine carries one of the highest metabolic risks among the newer antipsychotics.¹ It is also linked to an increased risk of developing type 2 diabetes.²

Olanzapine can raise blood sugar even in people who are not overweight.² So blood sugar is watched from the start, not only after weight changes.

Risperidone and prolactin

Prolactin is a hormone that controls breast-milk production. Risperidone blocks dopamine. Because dopamine normally keeps prolactin in check, prolactin can climb.³

Olanzapine blocks dopamine too, so why the difference? Risperidone crosses into the brain relatively poorly, and the pituitary gland, which makes prolactin, sits outside the brain's protective barrier. Risperidone therefore acts more strongly on the pituitary than it does on the brain itself.⁶

Two different things get counted here. A raised prolactin reading on a blood test is common: studies report it in 70 to 100 percent of people taking risperidone, against 10 to 40 percent on olanzapine.³ Noticing anything is much less common. Many people with a raised level have no symptoms at all, and symptoms usually appear only once the level climbs well above the normal range.³

When symptoms do come, they can include changes to periods, breast tenderness, unexpected breast-milk production, or lowered sex drive. Raised prolactin can also suppress ovulation and reduce fertility, which matters if you are planning a pregnancy, because it can happen with nothing obvious to notice.³⁶ A blood test settles the question. If it does become a problem, a prescriber may switch to a medicine like aripiprazole, which tends to lower it.³

Risperidone and movement effects

Both medicines can cause movement side effects, because both block dopamine. On average risperidone causes somewhat more of them than olanzapine, and the effect is dose-related: the higher the dose, the more likely they are.⁷ Pooling the head-to-head trials, about 25 percent of people on risperidone needed a medicine to settle these effects, against about 18 percent on olanzapine.⁷ A larger review of those trials found the same direction: fewer people on olanzapine than on risperidone needed a medicine to settle these effects.⁸ Individual trials have found no difference at all, so this is a tendency, not a rule.⁷

Three of these are worth being able to name. Parkinsonism is stiffness, slowed movement or a tremor. Dystonia is a muscle pulling into a spasm it will not release. Akathisia is an inner restlessness, a sense of not being able to sit still.⁷ None of them is something to put up with quietly, and all of them are worth reporting early, because a prescriber has several ways to address them.⁴

Tardive dyskinesia is a separate thing: the slow, involuntary movements that can develop after long use. Olanzapine appears to carry a lower risk of it than the older antipsychotics.² That is a comparison with an earlier generation of medicines, not a comparison between olanzapine and risperidone.

Why your health history matters

If weight, blood sugar or cholesterol are already a concern, olanzapine's metabolic load weighs more heavily. Diabetes is already two to three times more common in people living with bipolar disorder or schizophrenia.¹

Starting treatment and staying safe

Before starting one of these medicines, guidelines advise baseline checks of weight, blood pressure, fasting glucose and cholesterol.¹ Those guidelines are national rather than universal. A systematic evaluation of eighteen of them, from a range of countries, found the measurements they most often recommend are fasting glucose, body-mass index, fasting triglycerides and cholesterol, waist measurement and blood pressure.⁹ Fasting blood glucose in particular is checked before and after starting olanzapine.² The checks are then repeated at intervals, and the schedule differs between services and countries, so it is fair to ask what yours is and to expect a specific answer.

Weight gain can still happen. Some prescribers add metformin to help limit weight gain linked to antipsychotics.⁴

Stopping suddenly is the one change worth being firm about, and two different things can follow it. The first is that symptoms return.⁴ The second is separate: the body has adapted to the medicine and has to readapt. With olanzapine that can bring agitation and broken sleep, because olanzapine blocks several receptor systems besides dopamine; with risperidone, insomnia is the effect most often named.⁴ This is why prescribers usually taper olanzapine more gradually than risperidone. Feeling unwell in the days after stopping is not, on its own, proof that the illness has come back. Either way, plan any change with your prescriber rather than on your own.

Keeping a simple note of your mood, sleep and any side effects helps these reviews, so bring it to each appointment.

Where therapy fits

Medicine is one part of care, not the whole of it. These medicines are used within a broader biopsychosocial approach, alongside psychotherapy and social support.⁵

Individual and family therapy can address demoralisation, self-esteem and family relationships.⁵ If you want the wider picture, our pages on psychosis and mood disorders go further. You can also read how to find the right therapist.

Questions worth taking to your prescriber

Some answers depend on your history and your other medicines.

• How long before I should expect to notice a difference?
• Is it safe to drink alcohol while I take this?
• What should I do if I miss a dose?
• How often will we review how things are going?
• What are the options if this medicine is not right for me?

This article is for general information and is not a substitute for professional assessment or care. If this is affecting your life, consider reaching out to a qualified mental health professional.

References

1. [1] Williams KE, Rasgon NL. Endocrine and Metabolic Disorders (ch 27.7), metabolic syndrome and diabetes sections. In: Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 10th ed. Wolters Kluwer, 2017.
2. [2] Marder SR, Davis MC. Second-Generation Antipsychotics (ch 34.28). In: Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 10th ed. Wolters Kluwer, 2017.
3. [3] Williams KE, Rasgon NL. Endocrine and Metabolic Disorders (ch 27.7), hyperprolactinaemia section. In: Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 10th ed. Wolters Kluwer, 2017.
4. [4] Stahl SM. Prescriber's Guide: Stahl's Essential Psychopharmacology, 8th ed. Cambridge University Press, 2024. Olanzapine and Risperidone chapters.
5. [5] Gabbard GO (ed). Gabbard's Treatments of Psychiatric Disorders, 4th ed. American Psychiatric Publishing, 2007. Part IV: Schizophrenia and Other Psychotic Disorders, section introduction.
6. [6] Stojkovic M, Radmanovic B, Jovanovic M, Janjic V, Muric N, Ristic DI. Risperidone induced hyperprolactinemia: from basic to clinical studies. Frontiers in Psychiatry. 2022;13:874705. doi:10.3389/fpsyt.2022.874705
7. [7] Marder SR, Davis MC. Second-Generation Antipsychotics (ch 34.28), risperidone section. In: Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 10th ed. Wolters Kluwer, 2017.
8. [8] Komossa K, Rummel-Kluge C, Hunger H, Schmid F, Schwarz S, Duggan L, Kissling W, Leucht S. Olanzapine versus other atypical antipsychotics for schizophrenia. Cochrane Database of Systematic Reviews. 2010;(3):CD006654. doi:10.1002/14651858.CD006654.pub2
9. [9] De Hert M, Vancampfort D, Correll CU, Mercken V, Peuskens J, Sweers K, van Winkel R, Mitchell AJ. Guidelines for screening and monitoring of cardiometabolic risk in schizophrenia: systematic evaluation. British Journal of Psychiatry. 2011;199(2):99-105. doi:10.1192/bjp.bp.110.084665