New Study Reinforces That Antidepressants Treat Anxiety, But For How Long?

These studies compared different antidepressants to placebo, assessing their effectiveness in reducing anxiety, patient tolerability, and long-term adverse effects. The results showed that, although antidepressants provided a significant improvement in symptoms compared to placebo, the rate of treatment abandonment was higher among users of these medications due to side effects such as nausea, dizziness, drowsiness, dry mouth, excessive sweating, and sexual dysfunction.

Generalized anxiety disorder (GAD) is a mental condition characterized by excessive and persistent worry about various everyday situations, even when there is no real reason for it.

People with generalized anxiety disorder feel a constant state of apprehension and fear, which can affect their emotional and physical well-being. This disorder is quite common and affects approximately twice as many women as men. The main symptoms include restlessness, fatigue, difficulty concentrating, irritability, muscle tension, and sleep problems.

Treatment for generalized anxiety disorder involves both psychological approaches, such as cognitive behavioral therapy (CBT), and the use of medications.

Among the most commonly used drugs are antidepressants, especially selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). These medications work by increasing neurotransmitter levels in the brain, helping to regulate mood and reduce symptoms of anxiety.

Many studies have shown that antidepressants are more effective than placebo in treating generalized anxiety disorder, but new research continues to be done to better understand their effects and impact on patients’ quality of life.

To gain a more complete picture of the effectiveness of antidepressants in generalized anxiety disorder, researchers conducted a systematic review and meta-analysis of 37 randomized clinical trials, totaling more than 12,000 adult participants diagnosed with the disorder.

These studies compared different types of antidepressants to placebo, analyzing their effectiveness in reducing symptoms, patients’ tolerability of the medications, and potential adverse effects. Treatment duration ranged from four to 28 weeks.

The results showed that antidepressants provided significant improvement in anxiety symptoms compared to placebo. Efficacy was measured using the Hamilton Anxiety Rating Scale (HAM-A), and the data indicated that patients taking antidepressants were 41% more likely to experience at least a 50% reduction in symptoms compared to those taking placebo.

This means that for every seven patients treated with antidepressants, one will experience a significant improvement that would not have occurred with placebo alone. However, antidepressants also presented some challenges.

Although their compliance rate was similar to that of placebo (i.e., patients did not drop out of treatment more often because they found the drugs ineffective), they did have more side effects.

The rate of treatment discontinuation due to adverse reactions was higher among those taking antidepressants compared to those taking placebo. The main side effects reported included nausea, dizziness, drowsiness, dry mouth, excessive sweating, and sexual dysfunction.

The researchers concluded that antidepressants are effective in treating generalized anxiety disorder, but they emphasize that side effects may be an important factor for doctors and patients to consider when choosing the most appropriate treatment.

In addition, the review pointed out that most studies were conducted with people without serious medical comorbidities, leaving a gap in the understanding of how these medications may act in individuals who also suffer from other psychiatric or physical disorders.

In view of this, the scientists suggest that future research should better explore the effectiveness of antidepressants in more diverse populations, including people with other disorders associated with generalized anxiety disorder.

In addition, more detailed studies on the mechanisms of these medications and their variations among different groups of patients may help to develop more personalized and effective treatments for this anxiety disorder.

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Antidepressants versus placebo for generalised anxiety disorder (GAD) 

Katarina Kopcalic, Justin Arcaro, Antonio Pinto, Shehzad Ali, Corrado Barbui, Chiara Curatoli, Janet Martin and Giuseppe Guaiana

Cochrane Database of Systematic Reviews. 30 January 2025

DOI: 10.1002/14651858.CD012942.pub2

Abstract: 

Generalised anxiety disorder (GAD) is a mental health condition characterised by excessive anxiety and worry about everyday events. GAD is a common disorder and generally affects women twice as often as men. Treatments include various psychological and pharmacological therapies. Only one systematic review and meta‐analysis comparing all antidepressants to placebo has been done in the past. The studies included adults with moderate‐severe GAD and without any serious medical comorbidities. Few studies included participants with secondary psychiatric comorbidities. The double‐blind treatment duration ranged from four weeks to 28 weeks. Antidepressants have a benefit over placebo on rate of treatment response measured as a reduction of at least 50% on the Hamilton Anxiety Rating Scale (HAM‐A) (risk ratio (RR) 1.41, 95% confidence interval (CI) 1.29 to 1.55; 20 studies, 7267 participants; high‐certainty evidence). The magnitude of effect corresponds to a number needed to treat for an additional beneficial outcome (NNTB) of 7 (95% CI 5 to 9). Antidepressants have no difference in acceptability compared to placebo, measured as the number of participants who dropped out during the trial as a proportion of the total number of randomised participants (RR 1.03, 95% CI 0.93 to 1.14; 33 studies, 11,294 participants; high‐certainty evidence). Fewer participants dropped out due to a lack of efficacy in the antidepressant group compared to the placebo group (RR 0.41, 95% CI 0.33 to 0.50; 29 studies, 11,007 participants; high‐certainty evidence) with an NNTB of 27 (95% CI 24 to 32), and more participants dropped out due to adverse effects in the antidepressant group compared to placebo (RR 2.18, 95% CI 1.81 to 2.61; 32 studies, 11,793 participants; high‐certainty evidence) with a number needed to treat for an additional harmful outcome (NNTH) of 17 (95% CI 13 to 112). We observed similar findings when classes of antidepressants were compared with placebo. The certainty of the evidence for the analyses comparing different classes of antidepressants to placebo was high.