How do psychopaths act?

In the story I'm writing,the main character's sister is going to be a psychopath. How do psychopaths act?
And could you list some other interesting disorders (mental)?
Thanks.
xx

This is what wiki suggests about antisocial personality disorder (sociopaths)

Characteristics of people with antisocial personality disorder may include:
Persistent lying or stealing
Superficial charm
Apparent lack of remorse or empathy; inability to care about hurting others
Inability to keep jobs or stay in school
Impulsivity and/or recklessness
Lack of realistic, long-term goals — an inability or persistent failure to develop and execute long-term plans and goals
Inability to make or keep friends, or maintain relationships such as marriage
Poor behavioral controls — expressions of irritability, annoyance, impatience, threats, aggression, and verbal abuse; inadequate control of anger and temper
Narcissism, elevated self-appraisal or a sense of extreme entitlement
A persistent agitated or depressed feeling (dysphoria)
A history of childhood conduct disorders
Recurring difficulties with the law
Tendency to violate the boundaries and rights of others
Substance abuse
Aggressive, often violent behavior; prone to getting involved in fights
Inability to tolerate boredom
Disregard for the safety of self or others
Persistent attitude of irresponsibility and disregard for social rules, obligations, and norms
Difficulties with authority figures

Potential markers

Macdonald triad: bedwetting, a tendency to abuse animals, and pyromania (fire setting)

The APD etiology is currently associated with abusive, chaotic, or emotionally deprived home environments and with low socioeconomic status and urban settings. APD is also highly co-morbid with ADHD and Substance-Abuse Disorders

Interesting (?) disorders:
Anxiety Disorders: Generalized, Panic, Agoraphobia, PTSD, OCD
Dissociative disorders: amnesia, fugue, dissociative identity disorder (commonly known as multiple personality)
Mood disorders: bipolar I, II, Cyclothymia
Psychotic disorders: schizophrenia, delusional disorder
Personality disorders: Schizoid, Borderline, Histrionic, Schizotypal, Paranoid

Psychopaths love to kill and think about death and harmul things toward others. Some disorders are Delousional, Bipolar, OCD, ADHD. Try googling disorder and see what you get.

Ohhh!!! I'm good at thiss one. XD

Errrmm..

Make her obsess over stupid things... like keys! Lol
Give her a really bad temper... And make
her get angry at random.
And when shes all calm make her start talking to herself while staring at nothing. .
And if you really want to make her look crazy.. describe her as always covering her face with her hands.

Did you want this list so you could act insane.

No,I did not.
I'm creating a story.