Definition Obsessive-compulsive disorder (OCD) is represented by a diverse group of symptoms that include intrusive thoughts, rituals, preoccupations, and compulsions. These recurrent obsessions or compulsions cause severe distress to the person. The obsessions or compulsions are time-consuming and interfere significantly with the person's normal routine, occupational functioning, usual social activities, or relationships. A patient with OCD may have an obsession, a compulsion, or both.

Definition An obsession is a recurrent and intrusive thought, feeling, idea, or sensation. In contrast to an obsession, which is a mental event, a compulsion is a behavior. Specifically, a compulsion is a conscious, standardized, recurrent behavior, such as counting, checking, or avoiding. A patient with OCD realizes the irrationality of the obsession and experiences both the obsession and the compulsion as ego-dystonic (i.e., unwanted behavior). Although the compulsive act may be carried out in an attempt to reduce the anxiety associated with the obsession, it does not always succeed in doing so. The completion of the compulsive act may not affect the anxiety, and it may even increase the anxiety. Anxiety is also increased when a person resists carrying out a compulsion.

Epidemiology of OCD OCD is the fourth most common psychiatric disorder. Lifetime prevalence is 2-3% among adults. Male and Female are equally affected. In adolescents boys are more commonly affected than girls. Mean age of onset is 20 years.

Etiology of OCD Causes can be divided into three groups: biological, behavioral and psycho-social : A- Biological factors: 1. Neurotransmitters: serotonin. The many clinical drug trials that have been conducted support the hypothesis that dysregulation of serotonin is involved in the symptom formation of obsessions and compulsions in the disorder. 2. Brain imaging studies: increased activity in frontal lobes, basal ganglia( especially the caudate), and the cingulum. 3. Genetics: higher concordance rate for monozygotic twins than for dizygotic twins. Family studies :35%of first degree relatives of OCD patients are also affected.

B- Behavioral factors: 1.Conditioned stimuli 2.Avoidance strategies C- Psychosocial factors: 1. Personality factors: 15-35% of OCD patients have premorbid obsessional traits. Most patients with OCD do not have premorbid compulsions. 2. Psychodynamic factors: Obsessive compulsive neurosis: regression from the oedipal phase of psychosexual development.

Diagnostic criteria of OCD Either obsessions or compulsions: Obsessions as defined by (1), (2), (3), and (4): – recurrent and persistent thoughts, impulses, or images that are experienced, at some time during the disturbance, as intrusive and inappropriate and that cause marked anxiety or distress – the thoughts, impulses, or images are not simply excessive worries about real-life problems – the person attempts to ignore or suppress such thoughts, impulses, or images, or to neutralize them with some other thought or action – the person recognizes that the obsessional thoughts, impulses, or images are a product of his or her own mind (not imposed from without as in thought insertion) Compulsions as defined by (1) and (2): – repetitive behaviors (e.g., hand washing, ordering, checking) or mental acts (e.g., praying, counting, repeating words silently) that the person feels driven to perform in response to an obsession, or according to rules that must be applied rigidly – the behaviors or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these behaviors or mental acts either are not connected in a realistic way with what they are designed to neutralize or prevent or are clearly excessive

Diagnostic criteria of OCD At some point during the course of the disorder, the person has recognized that the obsessions or compulsions are excessive or unreasonable. Note: This does not apply to children. The obsessions or compulsions cause marked distress, are time- consuming (take more than 1 hour a day), or significantly interfere with the person's normal routine, occupational (or academic) functioning, or usual social activities or relationships. If another Axis I disorder is present, the content of the obsessions or compulsions is not restricted to it (e.g., preoccupation with food in the presence of an eating disorder; hair pulling in the presence of trichotillomania; concern with appearance in the presence of body dysmorphic disorder; preoccupation with drugs in the presence of a substance use disorder; preoccupation with having a serious illness in the presence of hypochondriasis; preoccupation with sexual urges or fantasies in the presence of a paraphilia; or guilty ruminations in the presence of major depressive disorder). The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition

Course and prognosis of OCD Sudden onset ( in one half of patients). Precipitating factors are present in(50-70%) of cases. There is often a delay of 5-10 years before patient comes to psychiatric attention. Presentation is heterogeneous; but there are certain patterns which are the major patterns: 1- contamination. 2- pathological doubt. 3- intrusive thoughts (mostly aggressive or sexual )-no compulsions 4- symmetry or precision : leads to compulsion of slowness. 5-other symptoms :religious obsessions, compulsive hoarding, … etc

Course is long (fluctuating or constant) % -significant improvement % -moderate improvement % -worsening course. 1/3 have a major depressive disorder. Suicide is a risk for all patients with OCD.

Differential diagnosis of OCD 1. Medical conditions: Tourette disorder and other tic disorders. Temporal lobe epilepsy( complex partial epilepsy). Head trauma. Post-encephalitic complications. 2. Psychiatric disorders: Schizophrenia. Obsessive-Compulsive personality disorder. Phobias. Depressive disorders.

Treatment of OCD Pharmacotherapy, behavioral therapy,or combination of both is effective in significantly reducing the symptoms of OCD. 1. Pharmacotherapy: Serotonin-specific reuptake inhibitors (SSRIs): first line drugs, effective with low side effect profile: flouxetine,sertraline,paroxetine, fluvoxamine, citalopram.Side effects: headache,nervousness GI upset, insomnia, sexual dysfunction. Clomipramine (Anafranil): a tricyclic compound which acts on serotonin and norepinephrine. It is effective but has many side effects similar to tricyclic antidepressant drugs. Other drugs: venlafaxine, MAOIs, augmentation drugs.

2. Behavioral therapy: it is as effective as drugs and its benefits may last longer than drugs. exposure &response prevention. desensitization. thought stopping. flooding. implosion therapy. aversive conditioning. 3. Other therapies : electroconvulsive therapy (ECT), Psychosurgery, Psychoanalysis. These treatments are used in resistant cases.