Treatment augmentation strategies for OCD: A review of 8 studies

5. Yousefzadeh F, Sahebolzamani E, Sadri A, et al. 5-Hydroxytryptophan as adjuvant therapy in treatment of moderate to severe obsessive-compulsive disorder: a doubleblind randomized trial with placebo control. Int Clin Psychopharmacol. 2020;35(5):254- 262. doi:10.1097/YIC.0000000000000321

Nutraceuticals such as glycine, milk thistle, myoinositol, and serotonin (5-hydroxytryptophan) have been proposed as augmentation options for OCD. Yousefzadeh et al¹⁴ investigated the effectiveness of using 5-hydroxytryptophan in treating OCD.

Study design

• In a 12-week, randomized, double-blind study, 60 patients who met DSM-5 criteria for moderate to severe OCD (Y-BOCS score >21) were randomly assigned to receive fluoxetine plus 5-hydroxytryptophan 100 mg twice daily or fluoxetine plus placebo.
• All patients were administered fluoxetine 20 mg/d for the first 4 weeks of the study followed by fluoxetine 60 mg/d for the remainder of the trial.
• Symptoms were assessed using the Y-BOCS at baseline, Week 4, Week 8, and Week 12.
• The primary outcome measure was the difference between the 2 groups in change in Y-BOCS total score from baseline to the end of the trial. Secondary outcome measures were the differences in the Y-BOCS obsession and compulsion subscale scores from baseline to Week 12.

Outcomes

• Compared to the placebo group, the 5-hydroxytryptophan group experienced a statistically significant greater improvement in Y-BOCS total score from baseline to Week 8 (P = .002) and Week 12 (P < .001).
• General linear model repeated measure showed significant effects for time × treatment interaction on Y-BOCS total (F = 12.07, df = 2.29, P < .001), obsession subscale (F = 8.25, df = 1.91, P = .001), and compulsion subscale scores (F = 6.64, df = 2.01, P = .002).
• The 5-hydroxytryptophan group demonstrated higher partial and complete treatment response rates (P = .032 and P = .001, respectively) as determined by change in Y-BOCS total score.
• The 5-hydroxytryptophan group showed a significant improvement from baseline to Week 12 in Y-BOCS obsession subscale score (5.23 ± 2.33 vs 3.53 ± 2.13, P = .009).
• There was a significant change from baseline to the end of the trial in the Y-BOCS compulsion subscale score (3.88 ± 2.04 vs 2.30 ± 1.37, P = .002).

Conclusion

• This trial demonstrated the potential benefits of 5-hydroxytryptophan in combination with fluoxetine for patients with OCD.

6. Mowla A, Ghaedsharaf M. Pregabalin augmentation for resistant obsessive-compulsive disorder: a double-blind placebo-controlled clinical trial. CNS Spectr. 2020;25(4):552-556. doi:10.1017/S1092852919001500

Glutamatergic dysfunction has been identified as a potential cause of OCD. Studies have found elevated levels of glutamatergic transmission in the cortical-striatal-thalamic circuit of the brain and elevated glutamate concentration in the CSF in patients with OCD. Pregabalin has multiple mechanisms of action that inhibit the release of glutamate. Mowla et al¹⁵ evaluated pregabalin as an augmentation treatment for resistant OCD.

Study design

• This 12-week, double-blind, placebo-controlled clinical trial evaluated the efficacy of adjunctive pregabalin in 56 patients who met DSM-5 criteria for OCD and had not responded to ≥12 weeks of treatment with an adequate and stable dose of sertraline (baseline Y-BOCS score ≥18).
• Individuals who had other major psychiatric disorders, major medical problems, were pregnant, or had past substance or alcohol abuse were excluded.
• Participants were randomly assigned to receive sertraline plus pregabalin (n = 28) or sertraline plus placebo (n = 28). Mean sertraline dosage was 256.5 mg/d; range was 100 mg/d to 300 mg/d. Pregabalin was started at 75 mg/d and increased by 75 mg increments weekly. The mean dosage was 185.9 mg/d; range was 75 mg/d to 225 mg/d.
• The primary outcome measure was change in Y-BOCS score. A decrease >35% in Y-BOCS score was considered a significant response rate.

Outcomes

• There was a statistically significant decrease in Y-BOCS score in patients who received pregabalin. In the pregabalin group, 57.14% of patients (n = 16) showed a >35% decrease in Y-BOCS score compared with 7.14% of patients (n = 2) in the placebo group (P < .01).
• The pregabalin group showed good tolerability and safety. There were no clinically significant adverse effects.

Conclusion

• In patients with treatment-resistant OCD who did not respond to sertraline monotherapy, augmentation with pregabalin significantly decreases Y-BOCS scores compared with placebo.

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