Dependent personality disorder is characterized by feelings of being overdependent on other people in an attempt to meet emotional needs, as well as going to great lengths to try and please others. Dependent personality disorder is one of the most commonly diagnosed personality disorders. This mental illness occurs equally in both men and women.
The appearance of dependent personality disorder typically becomes apparent in young adulthood or later in life as important adult relationships begin to manifest.  Personality disorders can be thought of as involving long-term patterns of thoughts and behaviors that are often quite unhealthy and very inflexible. 
People with this disorder find it very difficult to be alone. They will often go to painstaking efforts to be in the presence of others. They deeply rely on other people for support, reassurance, and comfort. When they don’t get this, they are then often engulfed with feelings of intense anxiety, feelings of abandonment, and loneliness.
With such intense desires to be near others, it can greatly hinder the relationships they have with other people. This creates a vicious cycle where their intense desire to depend on other people drives those very people away, thus intensifying their feelings of abandonment and emptiness.
According to Harvard Medical School, The seed of personality is one’s temperament, which is essentially one’s biological dispositions with a hereditary basis. Individual’s who suffer from dependent personality disorder usually have shown some sort of a tendency to be very cautious and fearful since their childhood. In their families, there is usually a high rate of mental illnesses like generalized anxiety disorder, certain phobias, and even avoidant personality disorder.  There has been extensive research done on dependent personality disorder. [4,5]
According to one study, it has been shown that individuals who have this disorder may also have separation anxiety disorder. Researchers concluded that dependent personality disorder was significantly associated with separation anxiety disorder in healthy subjects, drug abusers, alcoholics, and anorectic and bulimic patients. 
Another comprehensive study was done which observed whether people who suffered from this disorder also experienced physical abuse as compared to other personality disorders. The results from the study suggests first that this disorder subjects are at high risk of physical abuse by their spouses and second that this relationship was also found in other cluster C personality disorders, as well as in borderline personality disorder. 
People who have this disorder are often very critical of themselves. They find their worth from other people and when they can’t get what they want from someone, then they may feel rejected or hopeless. They may also be devastated by separation and loss, and they may go to extreme lengths, even when suffering from abuse, to stay in a relationship with someone.  Below, are some common symptoms of this disorder.
Easily hurt by criticism
Inability to cope with the demands of life
Avoiding being alone
Inability to accept disagreements
Difficulty making decisions without other’s approval
Acceptance of being mistreated
Completely devastated when relationships end
There are three different types of personality disorder criterion: Group A: marked by odd or eccentric behavior, Group B: marked by emotional or erratic behavior, and Group C: marked by feelings of anxiousness, nervous behavior. Dependent personality disorder is considered to be in group C. 
To get diagnosed with this mental illness, you will need to have a psychiatric evaluation by a psychiatrist or an accredited therapist/psychologist. They will ask you questions about your family history, what type of symptoms you’re experiencing, how these symptoms are interfering with your day to day life, and how long you’ve been experiencing these symptoms, among many other questions.
There is no cure for this disorder. However, it can be treated with psychotherapy and medication. For most mental illnesses, it is imperative that the patient commits to the treatment for the long-term. However, with this illness in particular, it may be counterproductive for the patient to be in therapy for several years since it would reinforce a dependent relationship with the patient and the therapist. Of course, there will most likely always be some type of dependency that will exist between the two.
Nevertheless, with dependent personality disorder, it appears that the shorter the therapy, the better.  The type of medication prescribed will depend on what specific symptoms the patient is experiencing and how severe they are.
1) “Dependent Personality Disorder.” Web MD. https://www.webmd.com/anxiety-panic/guide/dependent-personality-disorder#1
2) “Personality Disorders.” Medline Plus. https://medlineplus.gov/personalitydisorders.html
3) “Dependent personality disorder.” Harvard Medical School. https://www.health.harvard.edu/newsletter_article/Dependent_personality_disorder
4) “Rethinking dependent personality disorder: comparing different human relatedness in cultural contexts.” NCBI. https://www.ncbi.nlm.nih.gov/pubmed/19996716
5) “The dependent personality and interpersonal problems.” NCBI. https://www.ncbi.nlm.nih.gov/pubmed/8551295
6) “Comorbidity of dependent personality disorder and separation anxiety disorder in addictive disorders and in healthy subjects.” NCBI. https://www.ncbi.nlm.nih.gov/pubmed/12239442
7) “Dependent personality disorder and physical abuse.” NCBI. https://www.ncbi.nlm.nih.gov/pubmed/20537714
8) “Dependent Personality Disorder.” Psychology Today. https://www.psychologytoday.com/us/conditions/dependent-personality-disorder
9) “Dependent Personality Disorder (DPD).” Health Line. https://www.healthline.com/health/dependent-personality-disorder
10) “Dependent Personality Disorder Treatment.” Pych Central. https://psychcentral.com/disorders/dependent-personality-disorder/treatment/