Cluster A Personality Disorders (PD's) (Last Updated - 5/27/2003)
-odd, eccentric or weird group of personality disorders
-unable to develop social relationships
-more common among relatives w/ schizophrenia (esp. schizotypal PD)
-3 subtypes:
   A) Paranoid Personality Disorder:
      -assoc. w/ distrust and suspiciousness leading to patients being secretive & socially isolated
      -emotionally cold and odd
      -can see brief episodes of psychosis w/ persecutory delusions
      -may see pre-existing sensory impairments (Ex.) Deaf patients believe you are talking about them b/c they cannot hear you
      -common defense mechanism -> projection (attributing your thoughts to others)
      -symptoms tend to worsen w/ age
      -must differentiate from schizophrenia:
         1) Duration of symptoms: Schizophrenia (more recently) vs. Paranoid PD (always)
         2) Level of Functioning: Schizophrenia (non-functional) vs. Paranoid PD (relatively functional)
         3) Psychotic symptoms: Schizophrenia (yes) vs. Paranoid PD (no not usually)
   B) Schizoid Personality Disorder:
      -char. by detachment & restricted emotionality
      -patients are emotionally distant -> fear intimacy
      -disinterested in others -> enjoy being alone (not afraid to be) -> work @ night
      -voluntary social w/drawal
      -indifferent to praise or criticism
      -symptoms tend to worsen w/ age
      -no psychosis
   C) Schizotypal Personality Disorder:
      -char. by discomfort w/ social relationships (interpersonal awkwardness), thought discomfort & illusions
      -odd preoccupations, speech & affect
      -peculiar patterns of thinking (ideas of reference, persecutory illusions & magical thinking (lucky shoes or rituals)) -> differentiates
         schizotypal PD and schizoid PD
      -more common among relatives w/ schizophrenia
      -PD most resembling schizophrenia -> differentiate by the duration of symptoms:
         -Schizotypal (always) vs. Schizophrenia (more recently)
      -decreased platelet monoamine oxidase (MAO) levels -> less social (platelet MAO levels correlate w/ social functioning)

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References:

1) First Aid for the USMLE Step 1. Bhushan et al. 2002. pg. 135.
2) Kaplan USMLE Step 2 Lecture Notes: Psychiatry and Epidemiology & Ethics. Gonzalez-Mayo A. and Shaner, R. 2002. pg. 73-74.
3) Kaplan & Sadock's Synopsis of Psychiatry. 8th Edition. Kaplan, H. and Sadock, B. 1998. pg. 775-784.