What is the best approach for a 12-year-old patient with Obsessive-Compulsive Disorder (OCD) and anhedonia who has failed multiple Selective Serotonin Reuptake Inhibitors (SSRIs) and Luvox (fluvoxamine) and wants to focus on mood improvement, considering the addition of lamotrigine?

Treatment Approach for Treatment-Resistant OCD with Anhedonia in a 12-Year-Old

Lamotrigine is not a guideline-recommended augmentation strategy for treatment-resistant OCD in children or adults, and should not be added at this stage. Instead, you should follow the established OCD treatment algorithm by either switching to clomipramine or augmenting with evidence-based strategies before considering off-label glutamatergic agents 1.

Why Lamotrigine Is Not Appropriate Here

Lamotrigine lacks evidence for OCD treatment. While glutamatergic medications including lamotrigine have been evaluated as augmentation agents in treatment-resistant OCD, lamotrigine is mentioned only as part of a broader class without specific efficacy data 1. The evidence base for lamotrigine in OCD is insufficient compared to other augmentation strategies 1.

Lamotrigine's primary indication is bipolar disorder, not OCD. The drug has demonstrated efficacy in preventing mood episodes in bipolar I disorder, particularly depressive episodes, but has not shown efficacy in acute mania 2. In pediatric populations, lamotrigine is not FDA-approved for any indication in children under 12 years, and its use in bipolar disorder is only approved for maintenance therapy in adults 1, 2.

The anhedonia may be OCD-related, not a separate mood disorder. Before assuming this represents comorbid depression requiring mood stabilization, recognize that anhedonia can be a direct consequence of severe OCD itself 1.

Evidence-Based Next Steps for This Patient

First Priority: Optimize Current OCD Treatment

Switch to clomipramine monotherapy. After multiple SSRI failures including fluvoxamine (Luvox), clomipramine is the next evidence-based step 1. Clomipramine has demonstrated equivalent or potentially superior efficacy to SSRIs in OCD, though head-to-head trials show similar effectiveness 1.

• Start with careful dose titration given the patient's age
• Monitor for anticholinergic effects, cardiac conduction changes, and seizure risk 1
• Allow 8-12 weeks at maximum tolerated dose to assess response 1

Second Priority: Consider SSRI Augmentation Strategies

If switching is not preferred, augment with evidence-based agents:

Antipsychotic augmentation (risperidone or aripiprazole) has the strongest evidence for SSRI-resistant OCD 1. However, only one-third of patients show clinically meaningful response, and metabolic side effects require careful monitoring, particularly concerning in a 12-year-old 1.

Glutamatergic augmentation with N-acetylcysteine or memantine has emerging evidence in treatment-resistant OCD 1. N-acetylcysteine has the largest evidence base among glutamatergic agents, with three of five randomized controlled trials demonstrating superiority to placebo 1.

Third Priority: Ensure Adequate CBT Trial

Cognitive-behavioral therapy with exposure and response prevention (ERP) is essential. If not already implemented, CBT should be combined with pharmacotherapy, as effect sizes are larger with SSRI augmentation by CBT compared to antipsychotic augmentation 1.

• 10-20 sessions of individual or family-based CBT 1
• Can be delivered in-person or via internet protocols 1
• Consider intensive outpatient or residential treatment if standard approaches fail 1

Critical Caveats About Mood Symptoms

Rule out bipolar disorder before any mood stabilizer. The presence of comorbid bipolar disorder fundamentally changes the treatment algorithm, requiring mood stabilizers plus CBT rather than standard OCD treatment 1. In bipolar disorder with OCD, SSRIs may destabilize mood or precipitate mania 1.

Assess whether "anhedonia" represents:

• Treatment-emergent SSRI side effects (emotional blunting, sexual dysfunction) 1
• Demoralization from chronic, severe OCD 1
• True comorbid major depression requiring additional intervention 1
• Unrecognized bipolar depression (lamotrigine's actual indication) 1, 2

If true comorbid depression exists, continue optimizing OCD treatment first, as OCD improvement often resolves secondary depressive symptoms 1. SSRIs are recommended for comorbid depression in OCD, but the patient has already failed multiple SSRIs 1.

Why the Patient's "Focus on Mood" May Be Misleading

Approximately half of OCD patients fail to fully respond to first-line treatment, and this proportion can be higher in real-world settings 1. The patient's subjective focus on mood rather than obsessions/compulsions doesn't change the underlying diagnosis or evidence-based treatment pathway 1.

Anhedonia in OCD may improve with OCD-specific treatments rather than mood stabilizers 1. Jumping to lamotrigine bypasses multiple evidence-based interventions that directly target the primary disorder.

Practical Algorithm

1. Verify adequate SSRI trials: Maximum tolerated doses for 8-12 weeks each 1
2. Ensure CBT with ERP has been attempted or is being implemented 1
3. Switch to clomipramine as the next pharmacological step 1
4. If clomipramine fails or is not tolerated, consider SSRI augmentation with antipsychotics (risperidone/aripiprazole) or glutamatergic agents (N-acetylcysteine, memantine) 1
5. Only after three SRI trials (including clomipramine) and adequate CBT should you consider more intensive interventions 1

Lamotrigine should only be considered if:

• Bipolar disorder is definitively diagnosed (requires mood stabilization) 1, 2
• All evidence-based OCD augmentation strategies have failed 1
• The risk-benefit ratio is carefully discussed with family given off-label use in a child 1, 3, 2