Schizotypal Personality Disorder (STPD) is a mental health disorder that is characterized by a pattern of behavior and thinking that is eccentric, odd, and unusual. Individuals with STPD may experience social and interpersonal difficulties and may have unusual beliefs or experiences. 
The diagnostic criteria for STPD, as defined by the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition), include:
- Odd or eccentric behavior, appearance, or speech
- Paranoid or suspicious thinking
- Unusual beliefs or experiences, such as belief in psychic abilities, superstitions, or magical thinking
- Unusual perceptual experiences, such as hearing voices or experiencing illusions
- Odd or inappropriate affect (emotions)
- Lack of close friends or confidants
- Social anxiety that does not diminish with familiarity and tends to be associated with paranoid fears rather than negative judgments about oneself
Individuals with STPD may also experience cognitive and perceptual distortions, have difficulty with emotional regulation, and may experience transient psychotic-like symptoms, such as brief episodes of perceptual disturbances or delusional thinking. Treatment for STPD often involves a combination of medication and therapy, such as cognitive-behavioral therapy, social skills training, or psychodynamic therapy, aimed at reducing symptoms, improving social and interpersonal functioning, and enhancing overall quality of life.