Dependent personality disorder (DPD) is characterized by a pervasive psychological dependence on other people. This personality disorder is a long-term condition in which people depend on others to meet their emotional and physical needs, with only a minority achieving normal levels of independence. Dependent personality disorder is a cluster C personality disorder, which is characterized by excessive fear and anxiety. It begins prior to early adulthood, and it is present in a variety of contexts and is associated with inadequate functioning. Symptoms can include anything from extreme passivity, devastation or helplessness when relationships end, avoidance of responsibilities, and severe submission. People who have dependent personality disorder are overdependent on other people when it comes to making decisions. They cannot make a decision on their own as they need constant approval from other people. Consequently, individuals diagnosed with DPD tend to place needs and opinions of others above their own as they do not have the confidence to trust their decisions. This kind of behaviour can explain why people with DPD tend to show passive and clingy behaviour. These individuals display a fear of separation and cannot stand being alone. When alone, they experience feelings of isolation and loneliness due to their overwhelming dependence on other people. Generally people with DPD are also pessimistic: they expect the worst out of situations or believe that the worst will happen. They tend to be more introverted and are more sensitive to criticism and fear rejection. People with a history of neglect and an abusive upbringing are more susceptible to develop DPD, specifically those involved in long-term abusive relationships. Those with overprotective or authoritarian parents are also more at risk to develop DPD. Having a family history of anxiety disorder can play a role in the development of DPD as a 2004 twin study found a 0.81 heritability for personality disorders collectively. The exact cause of dependent personality disorder is unknown.