Addressing the Overgeneralization of Treatment in Obsessive-Compulsive and Related Disorders

The creation of the Obsessive-Compulsive and Related Disorders (OCRDs) category in the DSM-5 brought conditions such as hoarding disorder, trichotillomania (hair-pulling disorder; HPD), excoriation (skin-picking) disorder (SPD), and body dysmorphic disorder (BDD) under one diagnostic umbrella alongside OCD. While this classification has spurred valuable research and increased clinical recognition, it has also led to a significant clinical pitfall: the overgeneralization of treatment. Many clinicians incorrectly assume that because these conditions are grouped together, they share the same underlying mechanisms and will respond uniformly to identical interventions. In reality, assuming a "one-size-fits-all" approach leads to these conditions being misunderstood, misdiagnosed, and mistreated.

The illusion of shared mechanisms: form vs. function

The primary argument for grouping OCRDs was the shared presence of repetitive thoughts and behaviors, as well as a failure in behavioral inhibition. However, classifying these disorders based solely on the topography of their symptoms ignores their fundamental functional differences.

In OCD, compulsive rituals function as safety-seeking behaviors; they are performed to escape or neutralize the distress provoked by obsessional fears. BDD is the only other OCRD that consistently operates on this same functional template, where repetitive behaviors (like mirror checking or camouflaging) are performed to reduce anxiety related to appearance preoccupations.

Conversely, the repetitive behaviors seen in HPD and SPD are not driven by obsessional fears. Instead, hair pulling and skin picking are often utilized to regulate aversive affective states like tension, boredom, or stress, and are frequently accompanied by an immediate sense of pleasure, relief, or gratification during the act. Similarly, the excessive acquisition and saving behaviors in hoarding disorder are not motivated by intrusive obsessive fears, but rather by beliefs about the potential usefulness of possessions or intense sentimental attachment. Because hoarding does not result in an escape from obsessional anxiety in the way that OCD rituals do, it cannot be accurately conceptualized as "compulsive" in the OCD sense.

Pharmacological discrepancies

The DSM-5 justified the OCRD grouping in part by claiming a shared preferential response to serotonin reuptake inhibitors (SRIs). However, clinical research reveals highly inconsistent SRI efficacy across the OCRDs. While SRIs are efficacious for OCD and BDD, they are generally no more effective than a placebo in the treatment of HPD. Furthermore, patients with hoarding disorder are about 50% less likely to respond to SRIs than those with OCD. Consequently, assuming a uniform pharmacological approach across all OCRDs is not supported by empirical data.

Psychological treatment nuances

The assumption of shared mechanisms frequently leads clinicians to misapply standard Exposure and Response Prevention (ERP) across all OCRD presentations. While cognitive-behavioral therapies (CBT) are the treatments of choice across the spectrum, the type of CBT required varies drastically based on the disorder's function:

• OCD and BDD: Standard ERP is the empirically supported treatment of choice, as it directly targets the conditioned fear and safety-seeking avoidance behaviors that maintain these disorders. However, standard ERP must be modified and tailored to address the unique clinical features of BDD. Because individuals with BDD are often convinced they are physically deformed, they can be reluctant to engage in psychiatric treatment; as a result, the intervention requires more intensive engagement and ongoing motivational enhancement compared to standard OCD protocols. Exposure exercises and behavioural experiments must also be specifically adapted to address the profound social avoidance characteristic of BDD, distinguishing these approaches from typical OCD treatments. Furthermore, the treatment must integrate BDD-specific techniques, such as attentional or perceptual retraining (like mirror exposure). This helps patients shift from a narrow, critical focus on their perceived flaws to a broader, more holistic, and non-judgemental appraisal of their appearance. Finally, if the patient presents with specific accompanying symptoms such as skin picking or excessive cosmetic treatment-seeking, additional components like modified habit reversal training must be incorporated into the treatment plan.

• HPD and SPD: Because hair pulling and skin picking are not fear-driven, standard ERP is inappropriate. These body-focused repetitive behaviors require Habit Reversal Training (HRT) and stimulus control to disrupt motor patterns and increase awareness. Furthermore, because traditional HRT does not always address the intense emotions or sensory experiences driving focused pulling/picking, treatment often needs to be augmented with Acceptance and Commitment Therapy (ACT) or Dialectical Behavior Therapy (DBT) to improve distress tolerance and emotion regulation.

• Hoarding Disorder: Applying standard ERP to hoarding yields much lower and more gradual response rates than it does for other OCD presentations. Treatment for hoarding disorder requires specialized, multi-component CBT that integrates motivational enhancement, skills training in organization and decision-making, and in-vivo practice with sorting and discarding.

Conclusion

While the OCRD classification in the DSM-5 successfully highlights the presence of repetitive behaviors across several distinct conditions, mental health practitioners must look beyond this surface-level similarity. Accurately treating patients within the OCRD spectrum requires careful functional behavioral assessment to determine whether a behavior is driven by fear and avoidance, or by gratification and emotion regulation. Only by recognizing these distinct mechanisms can clinicians avoid the trap of overgeneralization and apply the specific, tailored interventions required for each unique disorder.

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