Background: Obsessive-compulsive disorder (OCD) is a common mental illness and a
ubiquitous cause of disability. Approximately half of the patients with OCD only partially respond or
do not respond at all to current ways of treatment. Even patients responding to treatment usually need
high doses of medication and/or intense psychotherapy for a long time. It is obvious that therapeutic
approaches to OCD need improving. In this article, we review the modalities of personalized medicine
Methods: We conducted a search in PubMed (until June 2015) and Scopus (until June 2015) by using
the following terms: “obsessive-compulsive disorder,” “personalized medicine,” “response prediction,”
“pharmacogenetics,” “therapeutic drug monitoring,” “EEG,” “neuroimaging” and “serotonin.” The literature about
neuroimaging including radiological techniques (positron emission tomography, single-photon emission tomography,
functional and morphometric magnetic resonance imaging and magnetic resonance spectroscopy) and
electroencephalography, therapeutic drug monitoring (measuring the plasma levels of drugs), pharmacogenetics (genes
encoding cytochrome P450 enzymes, serotonin transporter, serotonin receptors, norepinephrine transporter, dopamine
receptors, brain-derived neurotrophic factor [BDNF] and catechol-O-methyltransferase) and biochemistry (whole blood
serotonin levels and neuroendocrine challenge tests) is investigated.
Results: Pre-treatment changes in glucose metabolism shown by radiological instruments might be related to response to
medication. Increased alpha in EEG is predictive of good response whereas increased theta forecasts a poor response.
BDNF, serotonin receptors and glutamatergic and serotonergic transmission have been found to be somewhat related to
treatment response in OCD. Few studies on whole blood serotonin levels and hormone response to challenge with a serotonergic
medication in patients seem to have a predictive value in OCD treatment.
Conclusion: Although the studies to elaborate a personalized treatment of OCD have produced some promising results,
much more work is required to provide clinician with a reliable decision tree.