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Overview of OCD

By Irish Pharmacist - 14th Dec 2021

Obsessive compulsive woman aligning up pencils accurately on a glass table

A clinical look at obsessive compulsive disorder, which is ranked as one of the top 20 most disabling diseases by the WHO

Obsessive-compulsive disorder (OCD) is a psychiatric illness that has varying degrees of severity and it is characterised by obsessions or compulsions, but commonly both. Obsessions are intrusive thoughts, images or urges that occur repeatedly and that the person cannot get out of their mind. Compulsions are repetitive behaviours or mental acts that a person has an urge to continue. They can be overt (noticeable to others), ie, constantly washing their hands; or they can be covert, ie, a mental act that is not obvious to others, such as repeating a certain phrase over in your mind.

Body dysmorphic disorder (BDD) is a condition related to OCD characterised by severe preoccupation with a perceived physical defect. Body image problems cause distress and can cause anxiety, eating disorders and social phobia. Negative body image problems are a significant cause of many eating disorders. In many ways, BDD is like OCD — BDD also has obsessive characteristics, but in the case of BDD, the person is obsessed with an
imagined defect in his/her appearance. The treatment of BDD is similar to OCD. For this article, I will concentrate on OCD.

How common is OCD?

One-to-2 per cent of the population are thought to suffer from OCD, although some studies suggest it is as high as 2-to-3 per cent. OCD is more common in women than men. There are indications that there is a genetic link, with evidence that it runs in some families. The World Health Organisation rates obsessive-compulsive disorder as one of the top 20 most disabling diseases.

Problems with diagnosis

Obsessive-compulsive disorder can even occur in children as young as six or seven years, but most often starts in adolescence. It is suggested that 33-to-50 per cent of OCD begins in children and continues into adulthood. OCD often goes unrecognised and is under-diagnosed. Research shows that patients with OCD need to see three-to-four different medical professionals and spend an average of 10 years seeking help before they receive the correct diagnosis. More worryingly, studies indicate it takes an average of 17 years from the time OCD symptoms begin to the time they receive appropriate treatment.

There are several reasons OCD tends to be under-diagnosed and under-treated. People with OCD can often be secretive about their symptoms due to either a lack

of understanding about their condition, or embarrassment. Also, many doctors are not familiar with the symptoms of OCD or have not received sufficient training, or do not have enough time to enable diagnosis and give appropriate treatment. It doesn’t help that Ireland, compared to other European countries, has less psychiatrists and psychotherapists who specialise in OCD and waiting lists are longer than in other countries.


The most common symptoms of obsessive-compulsive disorder are:


Examples of obsessions include fear of causing harm to someone else; fear of harm coming to self; fear of contamination; need for symmetry or exactness; sexual and religious obsessions; fear of behaving unacceptably; and fear of making a mistake.


Compulsions can include behaviours such as cleaning, hand-washing, checking, ordering, arranging, hoarding, and asking for reassurance. Compulsions can also include mental acts such as counting, repeating words silently, and constant worries about past events. Trichotillomania is the urge to pull out the hair. This may include hair on the head or other places, ie, eyebrows, eyelashes. Trichotillomania occurs more in adolescents and young adults.

Most people acknowledge the senselessness of these thoughts and behaviours, as well as the wish to be rid of them. Most people with OCD suffer from both obsessions and compulsions. Common obsessions include unreasonable worry about harm, such as being responsible for yourself or someone else getting hurt, the fear of contamination (heightened during Covid), characterised by avoidance of situations where this ‘harm or contamination’ may occur. These obsessions cause compulsive behaviours, which are a mechanism used by the person to ease the associated anxiety and include the likes of excessive checking or cleaning.

Conditions which Co-exist with OCD

Several psychiatric conditions can also be present in those suffering from OCD. These include depression (50-to-60 per cent of OCD sufferers); specific phobias (22 per cent of OCD sufferers); social phobia (18 per cent of OCD sufferers); eating disorder (17 per cent of OCD sufferers); schizophrenia (14 per cent of OCD sufferers); alcohol dependence (14 per cent of OCD sufferers); panic disorder (12 per cent of OCD sufferers); and Tourette’s syndrome (7 per cent of OCD sufferers).

Management of OCD

The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) is considered the best test for assessing the severity of OCD; there is an adult and a child version. It is best to be referred by a GP to a psychiatrist who has
a speciality in OCD.

The following questions are advised by National Institute for Health and Care Excellence (NICE) in the UK to help determine if someone is suffering from OCD:

  • Do you wash or clean a lot?
  • Do you check things a lot?
  • Is there any thought that keeps bothering you that you would like to get rid of but cannot?
  • Do your daily activities take a long time to finish?
  • Are you concerned about orderliness or symmetry?
  • Do you get very annoyed if you cannot get a task completed?
  • Are you concerned about putting things in a special order?
  • Do you get very annoyed or upset by mess?

Severity of the condition can vary, and medical professionals must determine how much it is affecting the person’s ability to function in everyday life.

Management in Adults

Those with a milder form of OCD can be managed with low-intensity psychological treatment. International guidelines reckon that the psychological therapy called Cognitive Behavioural Therapy (CBT) is the most effective for OCD.

The two prominent features of OCD, over-estimations of danger and inflated beliefs of personal responsibility, benefited equally from CBT. CBT is a form of therapy that emphasises the important role of thinking in how we feel and what we do. CBT challenges the automatic thoughts and assumptions behind behaviour in anorexia.

In relation to OCD, CBT aims to remedy faulty reasoning that may have developed with the disorder. CBT encourages people to re-evaluate over-estimated beliefs about risk or personal responsibility, to regain a more realistic perspective. Inference-based treatment (IBT) is a method of psychological treatment sometimes used by psychologists in addition to CBT in OCD with obsessional doubt.

ERP (exposure and response prevention) is a technique in which the person is repeatedly exposed to the situation causing anxiety (ie, exposure to dirt) or are prevented from performing repetitive actions which lessen that anxiety (ie, washing their hands). This method is only undertaken with a professional therapist and is only used after extensive counselling and discussion with the person who understands fully what to expect and is ready to embrace his/her fears.

After an initial increase in anxiety, the level gradually decreases. When ERP is done effectively, the
person finds that once they confront their worst fears, nothing terrible actually happens, meaning the person can be ‘weanedoff’ their obsession or compulsion.

In the case of mild OCD, if low-intensity psychological treatment fails or the person opts not to have more intensive psychological treatment, medication such as a selective serotonin reuptake inhibitor (SSRI) antidepressant may be tried as the next step in therapy.

For people with more severe symptoms that are greatly affecting their quality of life (especially where low-intensity psychological treatment has failed), the next step in treatment is high-intensity CBT and ERP (more than 10 hours per person) or an SSRI. People with severe symptoms should always be offered high-intensity psychological therapy plus an SSRI.

Psychological treatment in children

For children, the steps taken and the use of psychological treatments like CBT and ERP are like those explained above for adults; it is important to involve family or carers, depending on the preference of the child. Children should only be treated by a specialist in OCD.

If psychological treatment fails, other factors that may be investigated by health professionals include the co-existence of other psychiatric conditions (such as depression), learning disorders, family problems, such as a marriage break-up of parents, and presence of mental health problems in the child’s parents.

In children over the age of eight, adding medication such as an SSRI might be appropriate in more severe cases, but only under specialist supervision, as there are risks as well as benefits.


According to NICE, CBT, including exposure and response prevention (ERP), should be first-line therapy for children, adolescents, and adults with mild-tomoderate OCD. Drug treatments (SSRIs) should be offered as an alternative to CBT (including ERP) for patients with severe OCD or who refuse or do not respond to psychological treatments.

CBT is a programme of structured selfhelp. Behavioural therapy began in the late 1960s and is the most used and most researched psychological treatment for OCD. It involves repeatedly confronting feared situations that are avoided (known as ‘exposure’). For CBT to be successful, the exposure must be long enough for the anxiety to reduce. CBT is based on the theory that people’s emotions and behaviour are influenced by their perception of events.

It is not the situation in itself that determines what people feel, but rather the way in which they react and feel about the situation. The situation does not change, ie, our hands are not clean. Our emotional responses are determined by our perception of the situation.

As well as a recognised therapy for OCD, CBT is a therapy used for a variety of other disorders, including depression, anxiety, sleep disorders, eating disorders and substance abuse, amongst others. CBT is a form of therapy that emphasises the important role of thinking in how we feel and what we do. The aim of CBT is to modify people’s thinking so that they can act and feel in more adaptive ways in response to a given event.

In essence, what CBT aims to achieve is to help people with mental health difficulties or other problems change how they view any given situation through how they think and act. Looking for a different outcome to the one that, whatever their illness may be, is compelling them to accept.

CBT tends to be a short therapy; however, the duration of treatment varies significantly. Duration of treatment depends on the severity of the problem and several other factors; for example, you could be suffering from more than one mental health difficulty, which may mean you need a longer duration of treatment. The shortest planned duration of therapy is usually about six sessions. Some people will only need a few sessions, while for others, it will take around 10-to-20 sessions.

A person will usually attend an ap pointment once a week or every fortnight, each lasting anything from 40 minutes up to an hour. Together with the therapist, a person will explore what their problems are with a view to gaining a greater understanding of them, and then develop a plan for tackling them. People learn a set of principles, skills and coping strategies that can be applied whenever needed. People may find them useful long after they have left therapy.

CBT is an interactive form of therapy. The person collaborates with their therapist as an active partner in their treatment.At first, the therapist will carry most of the session’s responsibilities, but as the therapy progresses and as the person learns how to use the coping skills and strategies shown during therapy, the person will take increased responsibility for their therapy.

The goal is the empowerment of the person in managing their recovery. Compared to other therapies like psychoanalysis, CBT normally focuses on what is going on in the present rather than the past. However, any good therapist may also look at a person’s past and how their past experiences impact on how they interpret the world now.

Between-session assignments are essential The sessions provide invaluable support. However, most of the benefits of CBT is the work that takes place between sessions. Persons are most likely to benefit from CBT if they are willing to do assignments at home. Completion of home assignments is also a strong indicator to the therapist of the person’s motivation to effect real change in their lives. People can develop and reinforce the skills they learned in therapy.

For example, if a young person is experiencing trichotillomania, they may feel that they are not able to take on social or work activities until they get over the condition due to being self-conscious of patches of hair missing. CBT may introduce them to an alternative viewpoint that trying some activity of this kind, however small-scale to begin with, will help them realise that their condition is not a big issue for their friends and peers. If they are open to testing this out, they might agree to do an assignment, like going to the cinema with a friend. As a result, they may make faster progress than someone who feels unable to take this risk.

Summarising CBT For OCD

CBT has two phases or goals. The first is to raise awareness of OCD and what behaviours, thoughts and emotions are leading to the mental health difficulties. The second is to use this knowledge to tackle the problem and to behave in a different way to relieve the underlying causes and symptoms of OCD. Of those who embrace CBT, approximately 75 per cent find significant improvement in obsessional symptoms after 10-to-20 sessions.

The risk of relapse after treatment is about 25 per cent, so additional treatment is needed.


Antidepressants are the mainstay of medication used to treat OCD. There is little evidence to show that medication such as SSRIs are more or less effective than CBT for treating OCD, however a combination of the two thought to increase treatment success. Studies show that antidepressants ease symptoms to at least a small degree in about 75-to-85 per cent of OCD patients. Approximately 50-to-60per cent of patients in clinical trials demonstrated at least a moderate response to antidepressants.

SSRIS in adults

SSRIs appear to be more effective for OCD than for body dysmorphic disorder (BDD). The SSRI’s primary clinical action is to increase the good mood neurotransmitter serotonin in the brain; despite years of research on the use of SSRIs (and other antidepressants) for OCD, the exact reason why they help OCD is not known.

SSRIs can cause an increased risk of suicidal thoughts and self-harm (this problem appears worse with paroxetine, which is why is fell out of favour in recent years) in people suffering from depression, therefore close monitoring (especially initially) must be performed by the person’s GP and other health professionals involved in the person’s care.

However, there is no current evidence linking the use of SSRIs for OCD per se with increased risk of suicide. Antidepressants are not habit-forming and craving and tolerance do not occur. Potential side-effects of SSRIs include nausea, worsening anxiety, suicidal thoughts, self-harm, akathisia (restlessness and the urge to move) and agitation;these side-effects more commonly occur in the first few weeks of treatment. Sideeffects like nausea and agitation usually subside after a few weeks.

SSRIs normally only take about two weeks to start relieving depression, however they take longerto relieve OCD symptoms. They can take up to 12 weeks to work for OCD symptoms, though they work on depressive symptoms quicker, usually within two weeks. The five SSRIs which are effective for OCD are fluoxetine, fluvoxamine, paroxetine, sertraline, or citalopram. There are no significant differences in efficacy between the different SSRIs for OCD. Higher doses are often required with SSRIs to relieve OCD than for depression. For example, fluoxetine dose may be increased to up to 60mg for OCD.

If there is no response to a standard dose, the maximum dose should be considered. SSRIs should be continued for at least 12 months to determine if they are working.


Another drug option if SSRI therapy fails is the tricyclic antidepressant clomipramine (Anafranil). Studies show that the efficacy of clomipramine is similar to SSRIs for relieving OCD. As with other tricyclic antidepressants, clomipramine can cause significant side-effects, including drowsiness, dry mouth, tachycardia, memory and concentration problems, urination problems (mainly in men) and weight gain.

Clomipramine was the most prescribed drug therapy for OCD in the past, however nowadays it is only prescribed in severe and resistant cases (since SSRIs were launched over 30 years ago), as SSRIs have fewer side-effects and are safer in overdose. Other tricyclic antidepressants like amitriptyline have not proven effective for OCD.

Some clinicians have added clomipramine to an SSRI like fluoxetine for resistant cases; however, this should be done only under strict supervision due to increased risk of side effects. The best add-on therapy to an antidepressant for OCD is CBT.

Dosages of antidepressants for OCD

Experience is that most people being prescribed antidepressants for OCD need high doses to obtain anti-obsessional effects. Studies show that the following dosages may be needed:

  • Fluoxetine: 40-to-80mg daily.
  • Sertraline: Up to 200mg daily.
  • Paroxetine: 40-to-60mg daily.
  • Citalopram: Up to 60mg daily.
  • Fluvoxamine: Up to 300mg daily.
  • Clomipramine: Up to 250mg daily.

Some clinicians around the world have found patients who failed to respond to high doses of antidepressants, but who improved on extremely low doses, such as fluoxetine 5-to-10mg daily or clomipramine 25mg daily. The effectiveness of lower doses for OCD has not been well reported in clinical literature and it is an area that warrants further research.

How long do antidepressants need to be used for?

There is no clear consensus how long patients need take antidepressants once they have been shown to work for an individual patient. Some patients can discontinue antidepressants after six-to-12 months. However, over half of OCD patients need to take at least a low-dose antidepressant for years, or even for life. Research indicates the risk of relapse is lower in patients who have undergone CBT and continue to use behaviour-therapy techniques longerterm. When an antidepressant is to be discontinued, it should be tapered very slowly, ideally over several months.

Other drug options

Antipsychotics are sometimes added to SSRIs in cases where SSRIs are not working adequately on their own. Obsessive compulsive disorder does not respond to antipsychotic drugs given on their own. However, studies have shown that for children and adults, adding first-generation (ie, haloperidol) or second-generation antipsychotics (ie, olanzapine, risperidone) in low dose to SSRIs may benefit resistant cases of OCD.

Antipsychotics have been shown to be particularly beneficial for people with OCD who also suffer from Tourette’s syndrome and tics. Tourette’s and tics appear to be more common in people suffering from OCD. Tourette’s is a neurological disorder characterised by the urge to perform repetitive movements or vocal sounds or sayings. These repetitive movements or sounds are called ‘tics’ and examples include twitches, eye-blinking, coughing, throat-clearing, sniffing, and facial movements.

Antipsychotics in combination with SSRIs should only be prescribed by a specialist and the person must be closely monitored for side-effects. Antipsychotics risk side-effects (more common with first-generation antipsychotics) including sedation, fatigue, headaches, blurred vision, weight gain, low blood sugar, sleep disturbances, stomach discomfort, constipation, vomiting, and interference with sexual life. Extrapyramidal symptoms (movement disorders like continual movements of the mouth, tongue, and jaw) are more common with first-generation antipsychotics and rare with second generation antipsychotics.

Other drugs are sometimes combined with ongoing SSRIs if the treatments described above have failed. Drugs that have commonly been used include the following: Buspirone (Buspar), lithium carbonate, clonazepam (Rivotril), methylphenidate (Ritalin) and other antidepressants, ie, trazodone (Molipaxin), duloxetine (Cymbalta), and venlafaxine (Efexor). None of these are licenced for OCD and studies have suggested their effectiveness is questionable. They should only be prescribed in resistant cases by a specialist experienced in OCD.

SSRIS in children and young people (Eight-to-18 years)

Caution is advised when prescribing SSRIs for younger people, as the risk of selfharm or suicide is greater in younger people. CBT therapy is the recommended first treatment choice for under-18s, and SSRIs should only be prescribed if CBT is ineffective. SSRIs should only be prescribed for young people in conjunction with psychological therapy following assessment by a child and adolescent psychiatrist who should also be involved in dosage changes and discontinuation.

Sertraline and fluoxetine are the only SSRIs licensed for OCD in under-18s, unless significant coexisting depression is evident, in which case only fluoxetine should be used.

If an SSRI does not work, another SSRI may be tried. Intensive CBT can be effective for under-18s, even in cases resistant to other psychological therapies. If the young person is still resistant to treatment, clomipramine (Anafranil) is an option, but can only be prescribed by a specialist. Clomipramine has a greater tendency to produce adverse effects than SSRIs.

Because of the risk of cardiac sideeffects, ECG and BP must be closely monitored. A low dose of clomipramine should be started and increased slowly according to response and the young person must be monitored regularly. Antipsychotics are sometimes used in addition to an antidepressant for young people if an SSRI is not affective alone, even though they are not licenced for OCD. Hospital treatment should always be a ‘last resort’ and only if community-based treatment fails.

Treatment Failure

Up to 40 per cent of people who present to psychiatrists fail to respond adequately to cognitive behavioural therapy, drugs, or a combination of the two. Neurosurgery may be considered for severely ill people who do not respond to CBT and medication. Risks, benefits, and long-term postoperative management should all be carefully considered before embarking on this treatment option.

Patient selection can be improved using neuroimaging. Stereotactic ablation and deep-brain stimulation are currently being explored and have shown promise.

How has Covid-19 impacted on patients with OCD?

The pandemic has increased anxiety and stress in the general population, but it has been well documented that when it comes to mental illnesses such as OCD, increased stress, worry, and isolation caused by health and employment concerns and restrictions have had a massive negative effect on symptoms. Combined with increased waiting times for treatment and less doctor-to-patient physical interaction and the reliance on virtual consultations (which doesn’t always suit patients), it has led to a perfect storm and set many patients backwards.

Due to the emphasis on cleanliness and infection control during the pandemic and the recommended disinfection measures, patients with contamination OCD (a common type of OCD where a person obsesses over contracting an illness or spreading germs) are more likely to obsess and worry about cleanliness and decontamination, both for themselves and their surrounds, thus increasing the fear of mixing with people due to fear of picking up the virus, which has increased isolation.

OCD Ireland

OCD Ireland is a national organisation for people with OCD and the related disorders of BDD and trichotillomania. OCD Ireland provides information and support for people with these disorders and for their family, friends, and carers, as well as interested professionals. They also promote awareness of the condition. They provide support, but not treatment of the condition. Their website is and it provides great information and advice on OCD.

References on request

Disclaimer: Brands mentioned in this article are meant as examples only and not
meant as preference to other brands.


Written and researched by Eamonn Brady (MPSI), owner of Whelehans Pharmacies in Mullingar Tel 04493 34591 (Pearse St) or 04493 10266 (Clonmore). www.whelehans.inet. Eamonn specialises in the supply of medicines and training needs of nursing homes throughout Ireland.







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