Week 4 Short Clinical Psychology: Obsessive-Compulsive and Related Disorders

Definition: Characterized by obsessions (intrusive, unwanted, distressing thoughts/urges) and compulsions (repetitive behaviors performed to reduce anxiety or prevent dread).
Diagnostic Criteria:
- Presence of obsessions, compulsions, or both.
- Symptoms must be time-consuming (> 1\,\text{hr/day}) or cause significant distress/impairment.
- Categorized separately from anxiety disorders in DSM-5.
Epidemiology:
- Prevalence: $\approx 2\%$ in Australia.
- Onset: Typically early adolescence to early adulthood (most by age $20$ ).
- Gender: No significant differences.
- Clinical presentation is extremely heterogeneous and highly comorbid with depression and anxiety.
Common Types:
- Cleaning/Contamination: Excessive washing and avoidance of contaminants (e.g., lead, germs).
- Forbidden thoughts: Aggressive, religious, or sexual intrusive thoughts often managed with mental rituals.
- Symmetry: Desire for objects to be perfectly ordered or actions to be even.

Neurobiological Model: Dysfunction in the cortico-striatal-thalamic-cortical loop and neurotransmitter dysfunction (Serotonin, Dopamine, Glutamate, GABA).
Cognitive Model (OCCWG): Identifies 6 biases: Inflated responsibility, over-importance of thoughts, controlling thoughts, over-estimation of threat, intolerance of uncertainty, and perfectionism.
Psychotherapy: CBT using Exposure and Response Prevention (ERP) involves gradual exposure to feared stimuli while preventing compulsions until habituation occurs.
Pharmacotherapy: SSRIs are shown to be efficacious.
Psychosurgery: Recommended for extreme, medication-resistant cases.
- Deep Brain Stimulation (DBS): Probes in the anterior limb of the internal capsule.
- Ablation: Surgical destruction of areas like the anterior cingulate or internal capsule.
- Capsulotomy: Specific lesions resulting in $\approx 50\%$ recovery in severe cases, though side effects include weight gain and executive dysfunction.

Definition: Preoccupation with perceived physical defects that are slight or unobservable to others, leading to repetitions (e.g., mirror checking, camouflaging).
Clinical Features:
- Preoccupation is present for > 1\,\text{hr/day}.
- Focus on an average of $5\text{--}7$ body parts over a lifetime (Phillips et al., 2005).
- Prevalence: $\approx 2\%$ ; more common in women.
- Insight is typically poor; high rates of dissatisfaction with plastic surgery.
Differential Diagnosis:
- BDD focus is specific to appearance defects, distinguishing it from Social Anxiety Disorder (general social evaluation) and Eating Disorders (weight/fat focus).
Treatment: CBT (focusing on reducing rumination and ERP) and SSRIs.

Definition: Persistent difficulty discarding possessions regardless of value, leading to clutter that makes living areas unusable.
Clinical Features:
- Onset usually in childhood/adolescence; severity increases with age.
- More common in men, though women seek treatment more frequently.
- High comorbidity (> 90\%), especially MDD, GAD, and ADHD (Inattention).
Differential Diagnosis:
- Depression: Clutter due to amotivation (individuals actually want to discard items).
- ADHD: Clutter due to disorganization (individuals do not experience distress discarding).
Treatment: Cognitive challenging, skills training, and exposure therapy.

Trichotillomania: Repetitive, uncontrollable hair pulling resulting in loss.
- Focused ( $25\%$ awareness) vs. Unfocused ( $75\%$ awareness).
Excoriation: Compulsive skin picking leading to tissue damage.
Epidemiology: Prevalence $\approx 1\text{--}5\%$ ; more frequently reported in females; onset after puberty.
Treatment:
- Stimulus control: Avoiding triggers (e.g., covering mirrors) and physical barriers (e.g., bandaids).
- Competing Response: Replacing the urge with a less harmful habit (e.g., applying moisturizer).
- Medications: Ineffective for excoriation; mixed evidence for HD and TTM.