Associate Professor Rocco Crino MAPS, School of Psychology, Charles Sturt University

The essential features of obsessive-compulsive disorder (OCD) are intrusive, unwanted, persistent thoughts, images or urges (obsesssions), and repetitive behaviours or mental acts (compulsions) that the individual conducts so as to prevent the outcome of the thoughts or lessen the anxiety, distress, discomfort or disgust generated by the thought. The most common themes of the intrusions are harm to self, harm to others, inappropriate sexual thoughts, blasphemy/religious scrupulosity, or violent/aggressive intrusions. The most frequent compulsions include decontamination (washing), checking, ordering, repeating, counting and praying. While at times compulsions appear to have logical connection with the intrusion (e.g., washing as a result of contamination concerns), there can also be no apparently logical connection evident (e.g., touching a certain number of times to prevent harm). In either case, compulsions need to be completed repeatedly or according to certain rules in order to diminish the threat or discomfort. Avoidance in OCD is commonplace, with individuals directly avoiding situations or cues that will trigger the intrusion, or engaging in more subtle avoidance or safety behaviours.

Individuals are often caught up in time consuming rituals or mental acts that interfere with day-to-day life, they avoid many situations, and the impact of the disorder often extends to family members. The personal impact of OCD is often heightened due to high comorbidity with depressive, anxiety and other conditions.

The 12-month prevalence of OCD in adults in Australia is approximately two per cent, with similar rates for other related obsessional disorders (hoarding disorder, body dysmorphic disorder, trichotillomania and excoriation). Although the peak age of onset of OCD is in adolescence and early adulthood, the disorder is not uncommon in children.

General principles of psychological assessment

Thorough clinical assessment and formulation is important. Although the diagnosis of OCD is relatively straightforward, the assessment of commonly occurring comorbid conditions such as depression, other anxiety disorders and tics may have treatment implications. A thorough assessment will also differentiate between OCD and DSM-5 related conditions (e.g., trichotollomania, body dysmorphic disorder) or unrelated disorders such as hypochondriasis and eating disorders. A detailed examination of maintaining factors (cognitive, behavioural, emotional and physiological) as part of the assessment process and ongoing formulation will assist in the direction of treatment.

Recommended OCD assessment tools include the clinician rated Yale-Brown Obsessive Compulsive Scale (YBOCS) (2nd Ed), the self-rated Padua Inventory (Washington State University Version) (PI-WSUR), and the Obsessive Compulsive Inventory-Revised, Dimensional OCD Scale (DOCS).

Evidence-based psychological treatment guidance

Cognitive behavioural interventions have the strongest empirical support in the treatment of OCD. The common elements of treatment are psychoeducation, cognitive interventions, behavioural interventions and relapse prevention.

  • Psychoeducation aims to normalise the experience of intrusive thoughts and highlight maintaining factors identified in the assessment process, which are then presented in a comprehensive model.
  • Cognitive interventions target the dysfunctional beliefs associated with the intrusions, in particular the personal appraisal and implications of the occurrence of the intrusive thought, as well as the content and the associated threat it poses.
  • Behavioural interventions take the form of exposure and response prevention, or behavioural experiments aimed at disconfirming the core fears and breaking the negatively reinforcing cycle of intrusion and ritual or compulsion. Exposure and response prevention is conducted in a graded, systematic manner with repeated confrontation of anxiety provoking cues and voluntary resistance to engaging in rituals. Behavioural experiments are designed to test the beliefs associated with the intrusion by having the individual engage in avoided activities or situations and generating alternative beliefs as a result.
  • Relapse prevention encourages individuals to continue to apply treatment principles, learn from lapses, and become their own therapist.

Emerging treatment directions for the future

Although not independently evaluated, acceptance and commitment therapy (ACT) has shown some promise in the treatment of OCD, and may be a more palatable intervention for some individuals. ACT does not involve direct exposure as in behavioural therapy, nor cognitive challenging in the same manner as traditional cognitive interventions. Instead, through a variety of procedures such as acceptance, cognitive defusion and mindfulness, the individual is encouraged not to avoid the intrusion nor try to control internal events, but rather to engage in behavioural commitment exercises instead of the rituals or compulsions.

Key reading and information sources

  • Obsessive-compulsive disorder: Core interventions in the treatment of obsessive-compulsive disorder and body dysmorphic disorder, National Institute of Clinical Excellence (NICE) guidelines (
  • Cognitive therapy for Obsessive Compulsive Disorder: A guide for professionals (Steketee & Willhelm, 2006)
  • Exposure and response (ritual) prevention for Obsessive Compulsive Disorder [Therapist guide] (Foa et al., 2012)
  • Exposure therapy for anxiety: Principles and practice (Abramowitz et al., 2013)


  • Abramowitz, J., Deacon, B. & Whiteside, S. (2013). Exposure therapy for anxiety: Principles and practice. New York: Guilford Publications.
  • Foa, E., Yadin, E. & Lichner, T. (2012). Exposure and response (ritual)prevention for Obsessive Compulsive Disorder (Therapist guide). New York: Oxford University Press.
  • Steketee, G. & Willhelm, S. (2006). Cognitive therapy for Obsessive Compulsive Disorder: A guide for professionals. Oakland California: New Harbinger Publications.

InPsych October 2014