Which personality disorder cluster is primarily defined by odd or eccentric behaviors?

The personality disorder cluster that is primarily defined by odd or eccentric behaviors is indeed Cluster A. This cluster includes disorders such as paranoid personality disorder, schizoid personality disorder, and schizotypal personality disorder. These disorders are characterized by peculiar thoughts, behaviors, and ways of relating to others that are often perceived as strange or eccentric.

Individuals with disorders in Cluster A may exhibit patterns of social awkwardness, unusual beliefs, and a tendency to be withdrawn or aloof. For example, someone with schizotypal personality disorder may have odd beliefs or magical thinking, making social interactions challenging. The defining feature of this cluster is the presence of these odd perceptions and behaviors, which distinguish it from Cluster B, which is marked by dramatic and emotional behaviors, and Cluster C, which involves anxious and fearful behaviors. Understanding these distinctions is vital for identifying and diagnosing personality disorders accurately.