The psychodynamic approach has been used to explain a wide range of phenomena including personality and moral development, gender identity, and the origins of psychological disorders, explaining them as unresolved conflicts from the psychosexual stages. There is large amounts of evidence for this, one example being Massie and Sjanbergs 2002 study who followed 76 people from infancy-30 finding that childhood trauma and poor quality attachment to parents were associated with a higher probability of having suffered a mental disorder.