Pharmacology of Cognition in Schizotypal Personality Disorder

Inclusion Criteria: * Subjects must be male or female * Medically and neurologically healthy (Medically healthy means that the patient does not have a major or partially treated medical condition that based on the judgment of the research clinician would either put the patient at increased risk and/or affect our findings. Common conditions include: high blood pressure, diabetes, uncontrolled asthma or COPD, abnormal heart rhythm, chronic viral infections. Neurologically healthy means that the patient has not experienced brain injury or head trauma associated with prolonged (e.g., \> 10 minutes) loss of consciousness, seizures or other conditions based on the research clinician's judgment would either put the patient at increased risk and/or affect our findings.) * Between 18 and 60 years of age * Patients must also be medication free (at least 2 weeks) while participating in guanfacine, except for the following medications: NSAIDS (eg, Advil), Tylenol, Levothyroxine (if on stable dose for 1 month, no symptoms of hypothyroidism and normal thyroid labs), Non-centrally acting antihistamines, H2 blockers (eg, Zantac), PPIs (eg, Prilosec, Prevacid). Research physician will make judgment on case-by-case basis based on risk to subject, and potential confounding effect on data validity. * Subjects in the SPD group must meet DSM-IV criteria for Schizotypal Personality Disorder. * Subjects in the AvPD group must meet DSM-IV criteria for Avoidant Personality Disorder and not meet criteria for schizotypal, paranoid, and schizoid personality disorder. In addition, the AvPD group must have fewer than 2 schizotypal traits. Exclusion Criteria: * Subjects may not have a significant medical illness (ie, insulin dependent diabetes, gastric/duodenal ulcer), or significant neurological illness (ie epilepsy, CMS, CVA, focal neurological lesion). * Any cardiovascular condition that, based on the research clinician's judgment (which includes cardiological consultation), would put the participant at increased risk will be considered an exclusion criteria. This would certainly include evidence by history or exam of heart block, tachyarrhythmia, angina, ventricular hypertrophy, those taking antihypertensives. Blood pressure parameters will be a \>25% decrease in mean arterial systolic blood pressure from baseline, an orthostatic decrease in systolic blood pressure of 20 mm Hg and/or in diastolic blood pressure of 10 mm Hg, and heart rate parameter will be below 55 bpm. * Participants are also excluded if they are more than 40% above ideal body weight. The weight limit helps insure that standard doses of guanfacine will not be given to patients who are extremely overweight who might then receive a lower concentration of these drugs in their central nervous system. * Subjects must also have a corrected or uncorrected visual acuity of 20/40 or better. * All participants meeting DSM IV criteria for any current or past history of sustained IV-substance dependence are excluded from the study. * Participants must be free of substance abuse for at least six months. Healthy Controls: Inclusion Criteria: * Healthy control subjects will be selected according to criteria noted in methods, and in age distribution comparable to our patients. * Healthy controls will be matched to patients on gender and parental socioeconomic status. * Healthy controls must be male or female between the ages of 18 and 60. Exclusion criteria: * for medical illness are identical to those of patients * must not meet criteria for a current or lifetime DSM-IV diagnosis of bipolar disorder, schizophrenia, schizoaffective disorder, or any Axis II disorder. * a current Axis I or II diagnosis or a family history of psychotic disorder will also be excluded. However, to avoid a group of HC's too highly groomed and unrepresentative of the general population we will not exclude HC subjects meeting criteria for a past Axis I diagnosis, such as adjustment disorder, dysthymic disorder, depressive disorder not otherwise specified, specific phobia, and sleep disorders. In addition subjects meeting criteria for a non-IV substance abuse disorder more than 6 months prior to enrollment will not be excluded.