Seroquel (quetiapine) is an atypical antipsychotic medication approved by the FDA to treat three conditions: schizophrenia, manic episodes in bipolar I disorder, and depressive episodes in bipolar disorder. It’s also widely prescribed off-label as an add-on treatment for major depression that hasn’t responded to antidepressants alone. The drug comes in immediate-release tablets ranging from 25 mg to 400 mg, and an extended-release version (Seroquel XR) is also available.
Schizophrenia
Seroquel is approved for treating schizophrenia in adults and adolescents aged 13 to 17. It works by influencing several chemical messengers in the brain, including dopamine and serotonin. By blocking certain dopamine receptors with moderate strength and also acting on serotonin receptors, it helps reduce hallucinations, disordered thinking, and other psychotic symptoms while causing fewer movement-related side effects than older antipsychotic drugs.
The drug has a binding profile similar to clozapine, one of the most effective antipsychotics available, though with lower overall receptor affinity. It also increases both noradrenaline and dopamine activity in the prefrontal cortex, the brain region most involved in planning, decision-making, and the cognitive difficulties that often accompany schizophrenia.
Bipolar Disorder
Seroquel has three separate approvals for bipolar disorder, each covering a different phase of the illness:
- Acute manic episodes (bipolar I): Approved for adults as a standalone treatment or combined with lithium or divalproex, and for children and adolescents aged 10 to 17 as a standalone treatment.
- Acute depressive episodes (bipolar disorder): Approved as a standalone treatment for adults only. Safety and effectiveness have not been established for anyone under 18 for this use.
- Long-term maintenance (bipolar I): Approved for adults as an add-on to lithium or divalproex to help prevent future mood episodes. This use is also limited to adults.
The bipolar depression approval is particularly notable because many medications that treat mania can worsen or fail to help the depressive side of bipolar disorder. Seroquel is one of a small number of drugs specifically approved for this purpose.
Major Depression (Off-Label)
One of the most common reasons doctors prescribe Seroquel today is for major depressive disorder (MDD) that hasn’t responded to standard antidepressants. This is an off-label use, meaning the FDA hasn’t formally approved it for this purpose, but clinical guidelines from both the Canadian Network for Mood and Anxiety Treatments and the American College of Physicians support it in specific situations.
The typical scenario: you’ve tried two or more antidepressants at adequate doses for adequate time, and your depression has only partially improved or hasn’t improved at all. At that point, adding a low-dose Seroquel to your existing antidepressant becomes a recognized option. The doses used for depression are generally lower than those used for schizophrenia or bipolar disorder.
In clinical trials, quetiapine performed well as an add-on treatment. A 2025 randomized trial found it outperformed lithium (a common augmentation choice) on depression scores, and patients in the quetiapine group also showed significantly better social functioning. A separate review found quetiapine produced higher remission rates than several other antipsychotics used for the same purpose. For depression with psychotic features (delusions or hallucinations alongside depressive symptoms), guidelines recommend quetiapine plus an antidepressant as a first-line combination.
Other Off-Label Uses
Seroquel is sometimes prescribed for conditions beyond its approved uses, though the evidence varies. For obsessive-compulsive disorder that hasn’t responded to standard treatment, adding quetiapine nearly tripled the odds of a meaningful response in clinical trials, making it one of the better-supported augmentation options for treatment-resistant OCD.
For agitation and behavioral symptoms in dementia, the evidence is less encouraging. A large comparative trial (CATIE-AD) found no significant difference in effectiveness between quetiapine and placebo for these symptoms, though quetiapine was better tolerated than some alternatives. Importantly, Seroquel carries a boxed warning against use in elderly patients with dementia-related psychosis due to an increased risk of death, so this use carries serious risk.
Low-dose Seroquel is also frequently prescribed for insomnia, largely because sedation is one of its most prominent effects. However, research specifically supporting this use is limited, and using an antipsychotic for sleep means accepting the metabolic side effects described below.
Common Side Effects
The side effect that affects daily life most is sedation. Seroquel is one of the more sedating atypical antipsychotics, which is why it’s often taken at bedtime. This sedation can be useful when insomnia accompanies the condition being treated, but it can also cause morning grogginess that interferes with functioning.
Weight gain is a significant concern. Higher doses increase both the amount of weight gained and the likelihood of clinically meaningful weight gain (defined as 7% or more of your starting body weight). Changes in cholesterol and other blood fats have also been documented, though blood pressure and blood sugar levels appear less directly affected by dose increases in the short term. Regular monitoring of weight, blood sugar, and lipid levels is standard practice while taking this medication.
Important Safety Warnings
Seroquel carries two FDA boxed warnings, the most serious type of safety alert.
The first concerns elderly patients with dementia-related psychosis. Antipsychotic drugs as a class increase the risk of death in this population, and Seroquel is not approved for this use. The second warning addresses suicidal thoughts and behaviors. In short-term studies, antidepressants (Seroquel is used as one for bipolar depression and off-label for MDD) increased the risk of suicidal thinking in children, adolescents, and young adults. This risk was not seen in adults over 24, and patients 65 and older actually showed reduced risk. Close monitoring is recommended for all ages during the first few months of treatment and whenever the dose changes, with family members encouraged to watch for new or worsening agitation, irritability, or unusual behavioral changes.