The drug of choice for obsessive – compulsive disorder :
**Core Concept**
Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by recurring, intrusive thoughts (obsessions) and repetitive behaviors (compulsions) that an individual feels compelled to perform. The pathophysiology of OCD involves dysregulation of the cortico-striatal-thalamo-cortical (CSTC) circuitry, particularly the orbitofrontal cortex, anterior cingulate cortex, and basal ganglia.
**Why the Correct Answer is Right**
The first-line pharmacological treatment for OCD is a selective serotonin reuptake inhibitor (SSRI), which increases the levels of serotonin in the synaptic cleft, thereby modulating the CSTC circuitry and reducing the severity of symptoms. Fluoxetine, a specific SSRI, is commonly prescribed for OCD due to its efficacy and tolerability. It acts by inhibiting the reuptake of serotonin, which enhances the neurotransmission of serotonin, including the 5-HT1A and 5-HT2 receptors.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because SSRIs are the preferred pharmacological treatment for OCD, and other classes of medications like tricyclic antidepressants (TCAs) or monoamine oxidase inhibitors (MAOIs) are not typically used as first-line agents.
**Option B:** This option is incorrect because although antipsychotics may be used as adjunctive therapy for OCD, they are not the primary treatment and are not suitable for long-term use due to potential side effects.
**Option C:** This option is incorrect because benzodiazepines are not effective in treating OCD and may even exacerbate symptoms in some cases.
**Clinical Pearl / High-Yield Fact**
SSRIs are the preferred treatment for OCD due to their efficacy and relatively favorable side effect profile, but they may take 4-6 weeks to exert their full therapeutic effect.
**Correct Answer: A. Fluoxetine**