Intrusive thought
Antidepressants which have been shown to be effective in treating OCD include fluvoxamine (trade name Luvox), fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), citalopram (Celexa), and clomipramine (Anafranil). Although SSRIs are known to be effective for OCD in general, there have been fewer studies on their effectiveness for intrusive thoughts. A retrospective chart review of patients with sexual symptoms treated with SSRIs showed the greatest improvement was in those with intrusive sexual obsessions typical of OCD. A study of ten patients with religious or blasphemous obsessions found that most patients responded to treatment with fluoxetine or clomipramine. Women with postpartum depression often have anxiety as well, and may need lower starting doses of SSRIs; they may not respond fully to the medication, and may benefit from adding cognitive behavioral or response prevention therapy.
Cause of obsessive-compulsive disorder
Dopaminergic systems are implicated in OCD by the efficacy of dopaminergic agents, the fact that PANDAS may be implicated, and by various neuroimaging studies. OCD may be treated with antipsychotic agents, however psychostimulants agents have also shown some promise in alleviating the symptoms of OCD. Although these need to be reconciled, they both implicate the dopaminergic systems. OCD also has a high comorbidity with ADHD, which is treated with psychostimulants and may result from increased phasic and decreased tonic signaling of dopaminergic neurons. PANDAS also affects the basal ganglia, where dopamine plays a large role as a neurotransmitter.