Obsessive-Compulsive Disorder (OCD)
Obsessive-Compulsive Disorder (OCD). Obsessions, compulsions, neurobiology and modern treatment with ERP, SSRIs and rTMS by psychiatrist Paschalis Gkikas in Athens.
Obsessive-Compulsive Disorder (OCD)
Obsessive-Compulsive Disorder is much more than a habit of cleaning or orderliness. It is a debilitating neuropsychiatric condition that traps the patient in relentless cycles of obsessions and compulsive behaviors — with serious effects on daily functioning.
What is Obsessive-Compulsive Disorder?
Obsessive-Compulsive Disorder (OCD, ICD-10: F42) is characterized by two core elements that feed each other in a closed loop:
- Obsessions: Recurrent, unwanted, intrusive thoughts, images or impulses that cause intense anxiety or distress. The patient recognizes them as irrational — but cannot “switch them off”.
- Compulsions: Repetitive behaviors or mental acts performed to reduce the anxiety caused by the obsession. They provide temporary relief — but reinforce the cycle in the long term.
According to the World Health Organization, OCD ranks among the 10 most disabling conditions worldwide.
Main OCD symptom dimensions
- Contamination and cleanliness: Fear of contamination by germs, chemicals or illness — accompanied by compulsive washing.
- Symmetry and order: Need for precision, symmetry or “correct” placement of objects.
- Harm obsessions: Recurrent images of harming oneself or others — which the patient rejects and fears intensely.
- Forbidden / taboo thoughts: Sexual, violent or religious obsessions that contradict the person’s values.
- Doubt and checking: Obsession with uncertainty — “what if I did not turn off the stove”, “what if I harmed someone”.
Clinical presentation and symptoms
Behavioral symptoms
- Repeated checking of locks, appliances or taps
- Cleaning rituals lasting several hours
- Reassurance seeking from others
- Avoidance of “dangerous” objects or situations
- Hoarding / inability to discard objects
- Mental rituals, such as counting, praying or repeating phrases
Functional symptoms
- Significant time loss because of rituals (>1 hour/day)
- Delay or inability to complete simple daily tasks
- Social withdrawal to conceal symptoms
- Extensive comorbidity with depression and anxiety disorders
Neurobiological basis
OCD is not “excessive conscientiousness” — it has a clear neuroanatomical substrate:
- CSTC circuit hyperactivity: The cortico-striato-thalamo-cortical circuit becomes trapped in a “loop” that does not close — the signal “this is dangerous / this was not done correctly” repeats without termination.
- Serotonergic dysfunction: A classic observation — explaining the effectiveness of SSRIs at high doses.
- Glutamatergic hyperactivity: Research findings that open therapeutic strategies with glutamatergic agents, such as N-acetylcysteine.
- Dorsolateral prefrontal cortex (DLPFC): Reduced capacity for top-down inhibition of pathological signals — the target of neuromodulation.
Treatment approach
OCD is treated — not merely managed. The combined approach of ERP and pharmacotherapy, optimized through PGx and enhanced with rTMS when indicated, leads to meaningful functional improvement for most patients.
First-line treatments
- High-dose SSRIs based on PGx: SSRIs are the proven pharmacological option for OCD — usually at doses higher than those used for depression and with a longer delay in response (8–12 weeks). Pharmacogenomic analysis directly selects the ideal molecule and prevents undesirable drug interactions.
- ERP (Exposure and Response Prevention): The specialized psychotherapeutic technique with the strongest evidence base for OCD. The patient is gradually exposed to obsessions without performing compulsions — dismantling the anxiety cycle.
Second-line and resistant cases
- rTMS for OCD: An approved treatment for OCD, targeting the prefrontal cortex or the supplementary motor area (SMA). It is used in patients who have not achieved adequate response with SSRIs and ERP — reorganizing dysfunctional activity in the CSTC circuit.
- Clomipramine: A tricyclic antidepressant with strong anti-obsessional action — an option in SSRI-resistant cases.
- Augmentation with antipsychotics: Low-dose atypical antipsychotics as adjunctive treatment.
- Deep TMS (Cool D-B80 Coil): A specially designed FDA-approved protocol for OCD — targeting deeper structures of the CSTC circuit.
Frequently asked questions (FAQ)
Is OCD the same disorder as “obsessive-compulsive personality”?
No. Obsessive-Compulsive Personality Disorder refers to stable personality traits, such as perfectionism, rigid morality and inability to delegate. OCD is a specific illness with obsessions and compulsions experienced as alien and unwanted.
How long do I need to take SSRIs for OCD?
At least 1–2 years after remission is achieved, to minimize relapse risk. Many patients need long-term treatment. The decision is made together with the psychiatrist based on the clinical picture.
Can OCD appear for the first time in adulthood?
Yes, although typical onset is in childhood or adolescence. In adults, it is often triggered by a stressful event, such as childbirth, loss or trauma. Perinatal OCD is particularly common and underdiagnosed.
Is rTMS effective for OCD?
Clinical data are positive, particularly for resistant cases. Learn more about rTMS for OCD. Paschalis Gkikas assesses individually whether it is an appropriate next clinical step for each patient.
