Missed diagnosis

It is important to screen for, assess and diagnose OCD. All too often, people suffering from OCD delay seeking treatment, are not being offered effective evidence-based therapies and are ending up chronically disabled, with the disorder significantly impacting on their life trajectory with severe impairment in occupational function, social skills and opportunities, and a negative impact on their sense of identity. The delays in seeking treatment are significant, with the duration of untreated illness estimated to be >7 years and the average age of presentation being 29 years. ^{Reference Pellegrini, Giobelli, Burato, di Salvo, Maina and Albert2} With most people suffering from OCD reporting a childhood onset, such a delay is unacceptable and better identification in childhood is a priority. For those who are successfully diagnosed, many are not receiving evidence-based therapies, with studies indicating that only around 30% receive exposure and response prevention therapy and that only 50% receive selective serotonin reuptake inhibitors. ^{Reference Brakoulias, Starcevic, Albert, Arumugham, Bailey and Belloch3} Systemic factors contributing to this treatment gap include stigma and a lack of trained therapists.

Shame and embarrassment are thought to play a significant role in the delays in treatment-seeking for people with OCD. Some sufferers avoid getting help and hide their symptoms. Considering that OCD can be familial, many parents either do not recognise or get help for their children, or ‘think’ that they are helping them by accommodating to their OCD. Presentations may be precipitated by job loss, relationship strain, financial hardship, the birth of a child or physical complications related to compulsive hand-washing or harmful methods used to prevent urination or defaecation. Presentations may also occur in the context of other mental disorders such as major depression or comorbid anxiety disorders, with over 50% having had a major depressive episode and approximately 70% having a co-occurring anxiety disorder. ^{Reference Brakoulias, Starcevic, Belloch, Brown, Ferrao and Fontenelle4} Because OCD can present with many different symptoms, it can be a difficult disorder to screen for. Screening instruments have tended to ask about the four main symptom groups for OCD. The National Institute for Health and Care Excellence guidelines recommends the Zohar–Fineberg Obsessive–Compulsive Screen ^{Reference Fineberg, Krishnaiah and Moberg5} for screening, which consists of five short questions assessing excessive washing/cleaning, checking, recurrent bothersome thoughts, delays in completing activities and concerns about orderliness or symmetry. The introduction of the concept of obsessive–compulsive and related disorders in both DSM5 and ICD-11 has improved clinicians’ ability to recognise and diagnose these disorders. ^{Reference Kogan, Stein, Rebello, Keeley, Chan and Fineberg6}

There is support in the literature for early identification of, and early intervention for, OCD, with earlier intervention being associated with better treatment outcomes. ^{Reference Fineberg, Dell’Osso, Albert, Maina, Geller and Carmi7} Earlier intervention can improve the life trajectory of an individual and can reduce the self-blame that may sometimes occur (remembering that suicidal attempts are not uncommon ^{Reference Brakoulias, Starcevic, Belloch, Brown, Ferrao and Fontenelle4} ). Education regarding the disorder can also assist families struggling with the disorder, by reducing any tendency to blame the sufferer or to accommodate to the obsessions and/or compulsions. Hence, OCD should not be missed.

Misdiagnosis

OCD is commonly misdiagnosed as psychosis, post-traumatic stress disorder (PTSD) or generalised anxiety disorder. The misdiagnosis of OCD as psychosis is concerning – particularly when people may be detained in hospital to prevent a high-risk act that the individual suffering from OCD fears that they might complete (but would never want to do). A common example is the detention of a mother of a newborn child who is involuntarily treated with sedating antipsychotic agents and taken away from her baby because of her obsessions that she may harm her baby. Screening tools (e.g. the Perinatal Obsessive Compulsive Scale) in the postnatal period may assist less experienced clinicians in detecting OCD. Trainee and junior psychiatrists in public mental health units may not see many people with primary OCD, but they need to be able to distinguish ego-dystonic obsessions from delusions, particularly when between 5 and 30% of people suffering from schizophrenia are thought to suffer also from obsessions and/or compulsions. ^{Reference Sharma and Reddy8} Obsessions can reach delusional intensity, and thus a lifespan approach to the assessment of the individual’s level of insight is useful. Another common source of confusion among less experienced clinicians is the reporting of a recurrent graphic or violent image (remembering that an obsession is a ‘recurrent thought, image or impulse’). Images can be misattributed to being a visual hallucination or a flashback. In contrast to obsessions, flashbacks are an intrusive image of a life-threating event that has occurred. Obsessions and compulsions in people with schizophrenia cause significant distress and disability, and do respond to evidence-based interventions for OCD. It should be noted that some people with schizophrenia, and their carers, may overemphasise the treatment of obsessions and compulsions and have difficulty accepting a diagnosis of schizophrenia, due to its more stigmatising nature. It is debatable whether people with schizophrenia have comorbid OCD, a schizo-obsessive disorder or simply obsessions and compulsions as part of their schizophrenia.

PTSD and OCD can co-occur. ^{Reference Brakoulias, Starcevic, Belloch, Brown, Ferrao and Fontenelle4} The co-occurrence of these two disorders can lead to diagnostic confusion. Some individuals have OCD prior to the onset of PTSD whereas others develop OCD following a traumatic event and may or may not have PTSD. Although someone may develop avoidance and/or repeated intrusive images (flashbacks) following a traumatic event that might resemble OCD, it is usually the excessively repetitive behaviour that reveals a diagnosis of OCD. A visual obsession is not a traumatic visual memory as in a flashback, and is more commonly centred around classic OCD themes of aggression/harm obsessions, sexual obsessions and contamination obsessions. One must approach such symptoms in a trauma-informed manner, because the reduction of an individual’s repeated hand-washing or -checking is likely to increase distress and may be seen as insensitive when linked to a traumatic event, e.g. excessive washing following sexual assault (often also associated with the phenomenon of mental contamination). Treatments for both PTSD and OCD involve exposure-based therapy, with treatment of the former tending to be prioritised over that of the latter. ^{Reference Gorbis, Gorbis and Jajoo9}

Excessive worry or rumination that may occur with generalised anxiety disorder and major depression can also be difficult to disentangle from obsessions. Individuals with generalised anxiety tend to worry about a wide variety of things, including ‘everyday’ worries such as getting to appointments on time, paying bills or being prepared for travel or an important event, whereas those with depressive ruminations tend to have more mood-congruent concerns with a tendency to self-blame. It is important to note that generalised anxiety disorder may occur in a third of people with OCD, ^{Reference Brakoulias, Starcevic, Belloch, Brown, Ferrao and Fontenelle4} and so it is possible that excessive worry and obsessions can co-exist. Pharmacological and psychological interventions are similar for both disorders, except that benzodiazepines tend to be effective for generalised anxiety disorder but are generally ineffective for OCD.

Obsessive–compulsive personality disorder (OCPD) also commonly co-occurs with OCD, at a rate of around 50%. ^{Reference Brakoulias, Starcevic, Belloch, Brown, Ferrao and Fontenelle4} OCPD requires a longer-term psychological approach and is less easily treated than OCD. A key difference between the two disorders is the ego-syntonicity associated with OCPD. There is also an absence of obsessions and compulsions in the true sense of recurrent and distressing thoughts, images and impulses and repetitive behaviours, with distress being experienced by those working or living with the person with OCPD rather than by the individual themselves. The features of this personality disorder are enduring and do not relapse and remit as is often the case with symptoms of OCD. Common characteristics of OCPD are perfectionism, over-conscientiousness, stubbornness and rigidity, needing to complete tasks themselves rather than delegating or working in a team, and themes of conservation, e.g. hoarding, thriftiness.

Clinicians commonly treating people with OCD are increasingly seeing some with autism spectrum disorder (ASD). ASD also co-occurs with OCD, but repetitive behaviours associated with ASD can often be misdiagnosed as OCD. Such behaviours may include repetitive behaviours including rocking, moving one’s hands, tapping, rigid routines and being ‘obsessed’ with narrow foci of interest. In ASD, repetitive movements can occur at times of both distress and joy; usually there is no clear association between the movement and an underlying cognition, thought or obsession. People with ASD can develop obsessions with poor levels of insight and less classic OCD themes, e.g. intense dislike of certain words, sounds or textures (perhaps linked to sensory processing), or needing certainty regarding specific facts. Like those with schizophrenia, some individuals with ASD may prefer a diagnostic label of OCD rather than ASD. Others are accepting of ASD in the context of schemes that offer more support when a diagnosis of ASD is present and increasing reports of celebrities being diagnosed as having ASD or ‘neurodivergence’.

Attention-deficit hyperactivity disorder (ADHD) has received much attention in the media, leading to increased awareness in the general population. Although genetic links are hypothesised among OCD, ADHD and tic disorders, and people with ADHD can engage in repetitive behaviours such as checking and ordering to cope with their attentional and executive dysfunction, and may daydream or ruminate, these behaviours can usually be distinguished from the unwanted, distressing, irrational urge-driven compulsions associated with OCD. Moreover, people with OCD can also misattribute their inattention to ADHD. Obsessions can be extremely distracting and may impair attention, and the repetitive nature of compulsions may be misinterpreted as fidgetiness or hyperactivity. In OCD, actions are usually taken with caution and there is a tendency to ‘internalise’, whereas in ADHD actions are more often impulsive and there is a tendency to ‘externalise’.

The shame and embarrassment associated with OCD, and the heterogeneity of its symptoms, can make the disorder elusive. However, screening for OCD can lead to earlier detection and treatment for an otherwise distressing and disabling disorder. With improved levels of experience in assessing and treating OCD, the risk of misdiagnosing co-occurring and phenomenologically similar diagnoses is likely to reduce. Clinician experience also assists in reducing misdiagnosis related to conscious and subconscious bias concerning the acceptability of certain diagnoses. With less chance of missing OCD or misdiagnosing OCD, we are likely to achieve better outcomes.