**Core Concept**
The autistic spectrum of disorders (ASD) encompasses a range of neurodevelopmental disorders characterized by difficulties in social interaction, verbal and nonverbal communication, and repetitive behaviors. The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) recognizes that certain personality disorders may share overlapping features with ASD.

**Why the Correct Answer is Right**
Research suggests that individuals with autism spectrum disorder often exhibit comorbid personality traits, including schizoid, schizotypal, and borderline personality features. This is due to the shared underlying neurobiological and cognitive mechanisms, such as impaired social cognition and attachment. Schizoid personality disorder is characterized by a lack of interest in social relationships and a tendency towards being aloof, which can be seen in some individuals with ASD. Schizotypal personality disorder is marked by eccentric behavior and anomalies of thinking and speech, which may be observed in individuals with ASD who exhibit repetitive behaviors and restricted interests. Borderline personality disorder is characterized by unstable relationships, emotional dysregulation, and impulsivity, which can be seen in individuals with ASD who experience significant social anxiety and difficulties with emotional regulation.

**Why Each Wrong Option is Incorrect**
**Option A:** Schizoid personality disorder is often comorbid with ASD, but it is not the only personality disorder that can be a part of the autistic spectrum of disorders.

**Option B:** Schizotypal personality disorder shares some features with ASD, but it is not the only personality disorder that can be comorbid with ASD.

**Clinical Pearl / High-Yield Fact**
The co-occurrence of personality disorders with ASD highlights the importance of comprehensive diagnostic assessments and individualized treatment plans that address the unique needs and challenges of each patient.

**Correct Answer Line**
✓ Correct Answer: D. All the above