The National Institutes of Health (NIH) defines OCD, or obsessive-compulsive disorder, as an anxiety disorder where the patient experiences obsessions (thoughts and ideas) and/or compulsions (driven behaviors). OCD is thought to be caused by a chemical imbalance of serotonin and dopamine in the brain.
Serotonin in the Brain
Harsányi et al., authors of the article "New Approach to Obsessive-Compulsive Disorder: Dopaminergic Theories" state that the basal ganglia in a OCD patient's brain has a decrease in serotonin activity; the decrease in serotonin was the original neurotransmitter theory for OCD.
Dopamine in the Brain
Harsányi et al. note that the cortico-striato-thalamic loops in a OCD patient's brain have a hyperfunction of dopamine; the dysfunction of the cortico-striato-thalamic loops are linked to the symptoms of OCD, which is a change in the neurotransmitter theory for OCD.
Current Treatment
The NIH states that selective serotonin reuptake inhibitors (SSRIs) are the first choice in medicine for OCD, which increase the levels of serotonin. Examples of SSRI approved for OCD are sertraline, paroxetine, fluvoxamine, fluoxetine and citalopram.
Limitations
Harsányi et al. state that SSRIs have limited success in treating OCD, since they only target serotonin.
Alternative Treatment
Harsányi et al. recommend using antipsychotics that have dopaminergic activity. The authors note that the antidopaminergic effect decreases the activity in the cortico-striato-thalamic loops and improves OCD symptoms.
