Differential Diagnosis for ASD Diagnostic Criteria Questions for Criteria B3

The provided question pertains to the diagnostic criteria for Autism Spectrum Disorder (ASD), specifically criteria B3, which involves restricted, repetitive patterns of behavior, interests, or activities. Given this context, the differential diagnosis can be organized as follows:

• Single Most Likely Diagnosis
  • Autism Spectrum Disorder (ASD): This is the most direct diagnosis related to the criteria B3, as it specifically involves patterns of behavior, interests, or activities that are restricted and repetitive, a core symptom of ASD.
• Other Likely Diagnoses
  • Obsessive-Compulsive Disorder (OCD): While not primarily characterized by social communication difficulties, OCD can present with repetitive behaviors or mental acts that an individual feels driven to perform, which might be confused with the repetitive behaviors seen in ASD.
  • Schizophrenia Spectrum Disorders: In some cases, especially in adults, repetitive behaviors or preoccupations can be a feature, though these are typically accompanied by more prominent psychotic symptoms.
  • Anxiety Disorders: Certain anxiety disorders, like generalized anxiety disorder or specific phobias, can lead to repetitive behaviors as a manifestation of anxiety, though these are generally more context-dependent than in ASD.
• Do Not Miss Diagnoses
  • Tardive Dyskinesia: A side effect of long-term use of neuroleptic drugs, characterized by repetitive, involuntary, purposeless movements. It's crucial to distinguish this from ASD or other psychiatric conditions to address the underlying cause.
  • Frontotemporal Dementia: In its early stages, frontotemporal dementia can present with changes in behavior, including repetitive behaviors, which might be mistaken for ASD, especially in adults without a prior diagnosis.
• Rare Diagnoses
  • Rett Syndrome: A genetic disorder that almost exclusively affects girls, characterized by severe impairment of intellectual and motor abilities, with repetitive hand movements. It's much rarer than ASD and has distinct genetic and clinical features.
  • Lesch-Nyhan Syndrome: A rare inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT), leading to self-mutilation and repetitive behaviors, among other symptoms.

Each of these diagnoses has distinct features, but they can sometimes present with overlapping symptoms, particularly the repetitive behaviors or restricted interests highlighted in ASD criteria B3. A comprehensive diagnostic evaluation is essential to accurately differentiate among these conditions.