Obsessive Compulsive Disorder

Obsessive compulsive disorder is a psychiatric condition characterised by obsessions and/or compulsions that consume significant time and cause clinically significant distress or functional impairment. It was historically classified within the anxiety disorder spectrum, given the substantial associated anxiety component. It is now recognised as a distinct diagnostic category, with characteristic phenomenology and distinct, though related, underlying neurobiology.

• Obsessions are recurrent, persistent, intrusive thoughts, urges or images, experienced as unwanted and causing significant anxiety or distress.
• Compulsions are repetitive behaviours or mental acts that the individual feels driven to perform. They are typically a response to an obsession or follow rigidly applied rules, and aim to reduce distress or prevent a feared outcome.

Diagnosis is frequently substantially delayed, given the significant shame and secrecy commonly associated with the content of obsessions and compulsions. Where the condition is suspected, make sensitive, direct clinical enquiry.

Pathophysiology and classification

• The underlying pathophysiology involves dysfunction within specific cortico-striato-thalamo-cortical neural circuitry. Functional neuroimaging shows characteristic patterns of altered activity within this circuit.
• There is strong evidence for serotonergic neurotransmitter system involvement. This provides the pharmacological basis for the effective role of serotonergic antidepressant treatment at the characteristically higher doses required for this condition.
• Common obsessional themes, with the compulsions that often accompany them:
  • Contamination fears (compulsive washing or cleaning).
  • Fear of causing harm to oneself or others (compulsive checking).
  • A need for symmetry or exactness (compulsive ordering or arranging).
  • Intrusive, unwanted thoughts of a taboo or distressing nature, including aggressive, sexual, or blasphemous content.
• The obsessional content carries no particular diagnostic or prognostic significance beyond characterising the individual presentation.
• Intrusive thoughts, however distressing or taboo in content, do not indicate any genuine desire or intent to act on them. This matters for accurate clinical understanding and patient reassurance.
• Insight into the excessive or unreasonable nature of the obsessions and compulsions varies considerably between individuals and can fluctuate over the course of the illness.
• A "poor insight" or "absent insight/delusional beliefs" specifier applies where the individual holds a firm, unwavering conviction that their obsessional beliefs are entirely accurate and reasonable. This is an important distinction from typical presentations with preserved insight, and requires careful differentiation from a primary psychotic disorder.

• Obsessions present as recurrent, intrusive, unwanted thoughts, urges or images. In the more typical presentation with preserved insight, the individual recognises them as excessive or unreasonable. They attempt to ignore, suppress, or neutralise them through a compulsion or other mental act, generally with limited or only temporary success. This causes significant anxiety and distress.
• Compulsions present as repetitive behaviours (including washing, checking, ordering, or counting) or mental acts (including praying, counting, or silently repeating specific words) that the individual feels driven to perform. They typically follow rigidly applied rules or respond to an obsession, and aim to reduce anxiety or prevent a feared outcome.
• Compulsions are characteristically not realistically connected to the feared outcome they are intended to prevent, or are clearly excessive relative to that outcome.
• The obsessions and compulsions are typically time consuming (occupying more than one hour per day, a commonly used, though not absolute, severity threshold). They cause clinically significant distress or functional impairment across occupational, social, or personal domains.
• Pattern and severity vary considerably between individuals. In many cases they fluctuate over the course of the illness, often with periods of relative worsening during significant stress.
• Significant shame and secrecy about the content of obsessions and compulsions frequently contributes to substantial diagnostic delay. This is particularly so where taboo themes (aggressive, sexual, or blasphemous content) are present.
• Affected individuals are often reluctant to disclose the nature of their symptoms even to close family members, let alone treating clinicians. Disclosure needs specific, sensitive, direct enquiry that creates a safe and non-judgmental space.

• Diagnosis is established through full clinical psychiatric assessment against the established diagnostic criteria. Specific, direct, sensitive enquiry about obsessions and compulsions is essential, given the frequent reluctance to disclose these symptoms spontaneously.
• Validated screening and severity rating instruments (including the Yale-Brown Obsessive Compulsive Scale) support structured assessment and ongoing monitoring of treatment response.
• Assess the level of insight, and screen for coexisting psychiatric conditions. These include depressive disorders and other anxiety disorders. In children and adolescents, also screen for tic disorders, given a recognised association with obsessive compulsive disorder in this population.
• Distinguish obsessive compulsive disorder from obsessive compulsive personality disorder. The latter is a distinct condition characterised by a pervasive pattern of preoccupation with orderliness, perfectionism, and control. It is generally experienced as ego-syntonic, that is, consistent with the individual's own sense of self and values. This contrasts with the ego-dystonic, distressing, unwanted nature of genuine obsessive compulsive disorder symptoms.
• The two conditions have differing underlying psychopathology and treatment approach, despite similar names.
• Assess carefully for the "poor insight" specifier, and distinguish the disorder from a primary psychotic disorder where insight is significantly impaired. This is sometimes clinically challenging.

• Cognitive behavioural therapy incorporating exposure and response prevention is the first line, most strongly evidence supported psychological treatment. It is a highly effective, specifically tailored approach.
• Exposure and response prevention involves structured, graded exposure to the feared situations or triggers associated with the obsessions, while actively preventing the compulsive behaviour. Through direct, repeated experience, the individual learns that the feared outcome does not occur. They also learn that the anxiety diminishes naturally over time without the compulsion.
• Selective serotonin reuptake inhibitor antidepressants are first line pharmacological treatment. They require substantially higher doses than are typically used for depression or the standard anxiety disorders. A longer treatment trial is also needed before concluding inadequate response (generally at least twelve weeks at an adequate dose). This reflects the different treatment response pattern of this condition.
• Clomipramine, a tricyclic antidepressant with potent serotonergic activity, is an effective alternative. It is particularly relevant for patients not responding to an adequate trial of a selective serotonin reuptake inhibitor. It is generally reserved as a subsequent option, given its less favourable tolerability and safety profile.
• Combined treatment, with both cognitive behavioural therapy with exposure and response prevention and pharmacotherapy, is generally recommended for more severe presentations, given evidence of superior outcomes.
• Treatment resistant disease follows inadequate response to adequate trials of both first line psychological and pharmacological treatment. It warrants specialist psychiatric reassessment.
• Options include augmentation strategies (addition of a low dose antipsychotic medication to the existing serotonergic antidepressant). For the most severe, refractory presentations, consider specialist interventional treatment including deep brain stimulation, delivered within highly specialised tertiary services.
• Full psychoeducation addresses the nature of the condition. It includes the reassuring distinction between the content of intrusive obsessional thoughts and any genuine desire or intent to act on them. This is particularly important given the significant shame frequently experienced regarding taboo obsessional content.
• Where relevant and with consent, involve and educate the family. Family accommodation of compulsive behaviours is a well recognised pattern. While well intentioned, it can inadvertently perpetuate and reinforce the condition. Family focused psychoeducation addressing this pattern is a valuable component of treatment.
• Together, these measures underpin effective longitudinal management of this frequently significantly impairing, though generally substantially treatable, condition.