A personality disorder is a problem deriving from a characteristic in the way a person is that limits them in their daily life. Personality disorders are, therefore, styles of maladaptive functioning that affect a person’s ability to relate to their environment. People who have a personality disorder are inflexible when facing responsibilities and their daily relationships. They have an altered perception of their personal image and the environment, as well as possessing behaviour patterns that can cause them physical and psychological harm.

When an individual’s personality trait hinders their daily functioning without being limiting, this could be considered a maladaptive personality trait. Each case has to be assessed on its own merits. Assessing personality characteristics allows the therapeutic programme to be adapted to the needs of each person, be they an adolescent or an adult.

Personality disorders in adult life are classified into three groups:

• Group A personality disorder: paranoid, schizoid and schizotypal personality disorder.
• Group B personality disorder: antisocial personality disorder, borderline personality disorder, histrionic and narcissistic disorder.
• Group C personality disorder: avoidant, dependent and obsessive-compulsive personality disorder.

Adolescents and personality disorders

Personality traits start to appear in adolescence even though all the diagnostic criteria for a personality disorder are not yet met. An adolescent might present significant difficulties in regulating their emotions and controlling their impulses, which may pose a risk for them and people around them. Some examples are self-harming, risky sexual behaviour, substance abuse, theft or violence.

Regarding academic performance, there is often a significant decrease and demotivation, in the most serious cases in the form of school absenteeism and classroom conflicts. In cases during adolescence, behaviour disorders cause relationships with others to be highly unstable, with behaviour that ranges between self-reliance and high dependence on others, impulsiveness when faced with intense fear, or intolerance to limits or when faced with intransigence and control from others.