Is Citalopram the Best SSRI for Mood and Anxiety?

Treating Mood and Anxiety with Citalopram

If your patient is asking, “Is citalopram the best antidepressant for me?”—the answer may not lie in guidelines alone, but in their genes. Citalopram remains one of the most commonly prescribed SSRIs in the UK and globally. It’s often chosen for its clean pharmacological profile and widespread familiarity. But as queries like “citalopram or sertraline” dominate UK search traffic, it’s clear patients are looking for evidence-backed comparisons. The truth is: what’s "best" depends on individual biology—and pharmacogenomic testing can reveal the answer.

Why Citalopram?

Citalopram is a selective serotonin reuptake inhibitor (SSRI) widely prescribed for major depressive disorder and generalised anxiety disorder. It’s often seen as a well-tolerated first-line option due to its high selectivity for the serotonin transporter and relatively low anticholinergic or noradrenergic activity.

But tolerability isn't universal. Some patients struggle with fatigue, nausea, sexual side effects, or poor therapeutic response—despite textbook prescribing.

Understanding Citalopram’s Variability: CYP2C19 and the Role of Pharmacogenomics

The most significant genetic factor affecting citalopram response is the CYP2C19 enzyme, responsible for its primary metabolism. Variations in this gene mean some patients will clear citalopram too rapidly (reducing efficacy), while others will accumulate it to potentially toxic levels, increasing the risk of side effects like QT interval prolongation.

Pharmacogenomic testing—available from services like AttoDiagnostics across the UK—can classify patients as:

• Ultra-rapid metabolisers – may require alternative medication

• Poor metabolisers – may need dose reduction or ECG monitoring

• Intermediate/normal metabolisers – likely to respond as expected

This testing can reduce the trial-and-error prescribing process, supporting faster symptom resolution and minimising avoidable harm.

Citalopram vs Sertraline: What Makes the Difference?

Both citalopram and sertraline are NHS-approved SSRIs with similar indications, but their pharmacogenetic considerations differ:

For patients who've tried both, pharmacogenomic profiling can help explain why one worked better—or why neither felt effective.

PGx in Practice: How and When to Test

Pharmacogenomic testing is now recommended by many international guidelines (CPIC, DPWG) for antidepressants including SSRIs. In the UK, services like AttoDiagnostics offer saliva-based PGx testing with no need for blood draws. Results typically return within two weeks.

• Who to test: Patients with treatment resistance, intolerable side effects, or multi-drug regimens

• Where to test: Search for "PGx testing near me" or use a UK pharmacogenomic provider such as AttoDiagnostics

• What it reveals: Evidence-based dosing adjustments or recommendations for alternative SSRIs

Helping patients choosen the right medication first time has a multitude of benefits, ranging from faster treatment outcomes to reducing costs to the NHS.

SSRIs Are Not Interchangeable—And Citalopram Isn’t Always Best

The NICE pathway may list SSRIs as a class, but clinicians know that individual response varies widely. The expanding evidence base around pharmacogenomics makes a strong case for routine integration in psychiatric prescribing—especially when treating mood and anxiety disorders. So, is citalopram the best SSRI? Sometimes. But increasingly, it’s the patient’s DNA—not the drug class—that holds the answer.

If you are interetsed in securing a private PGx test, head to AttoPGx. If you're a Doctor or Mental Health Practitioner, learn about pharmacogenomics below:

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