A variety of complex explanations for depression came into being during the latter part of the Age of Enlightenment. Some doctors and authors suggested that aggression was the real root of depression. They advocated exercise, music, drugs and diet, and stressed the importance of discussing problems with a close friend, or a doctor. Others thought that depression was caused by an internal conflict between unacceptable impulses and a person's conscience. In contrast, advances in general medical knowledge caused other scientists to believe in and search for organic (physical) causes of depression.
Towards the beginning of the 19th century, new therapies for depression included water immersion (keeping people under water for as long as possible without drowning them) and a special spinning stool to induce dizziness (to rearrange the contents of the brain into the correct positions). In addition, Benjamin Franklin introduced an early form of electroshock therapy. Horseback riding, special diets, enemas and vomiting were also recommended therapy.
Depression was first distinguished from schizophrenia in 1895 by the German psychiatrist Emil Kraepelin. During this same period, psychodynamic theory was invented and psychoanalysis (the psychotherapy based upon the psychodynamic theory) became increasingly popular as a treatment for depression. In a 1917 essay, Sigmund Freud explained melancholia as a response to loss: either real loss (such as the death of a spouse), or symbolic loss (such as the failure to achieve an important goal). Freud believed that a person's unconscious anger over loss weakened the ego, resulting in self-hate and self-destructive behavior. Freud advocated psychoanalysis (the "talking cure") to resolve unconscious conflicts and reduce the need for self-abusive thoughts and behavior. Other doctors during this time viewed depression as a physical disease and a brain disorder.
Treatments during the late 19th and early 20th centuries were usually inadequate for people with severe depression. As a result, many desperate people were treated with lobotomy (the surgical destruction of the frontal portion of a person's brain which had become popular as a "calming" treatment at this time). Lobotomies were often unsuccessful, causing personality changes, inability to make decisions, and poor judgment; or worse, coma and sometimes death. Electroconvulsive therapy (discussed in a later section of our paper), was a popular treatment for schizophrenics, but this treatment was also used for depressed people.
Influenced by hundreds of years of back and forth debate as to whether depression was best thought of as a mental or physical problem, and by increasing knowledge of the brain and brain chemistry, the medical community of the 1950s and 60's accepted a classification that divided depression into subtypes based on supposed causes of the disorder. "Endogenous" depression came from within the body and was caused by genetics or some other physical problem. People with endogenous depression were supposed to view themselves as the source of their own suffering and to think that everything was their fault. Their emotional pain was thought to be unaffected by the attitudes or responses of the people around them.
In contrast, "neurotic" or "reactive" depression was caused by some significant change in the environment, such as the death of a spouse, or other significant loss, such as the loss of a job. Individuals with reactive depression were thought to feel isolated, victimized and abandoned, and to view the cause of their problems as something external to themselves. People with reactive depression were thought to develop somatic (physical) symptoms and to make suicide attempts as a means of mobilizing support from the people around them.
The 1950s were also important in the search for organic causes and treatments for mental illness. In 1952, doctors noticed that a tuberculosis medication (isoniazid) was also useful in treating people with depression. Shortly after this significant finding, the practice of using medications to treat mental illness gained full steam. In response, psychiatry, which had previously looked to psychotherapy as their therapy of choice, started to emphasize the use of medications as primary treatments for mental illnesses. During the same period, evolving theories in psychology added to the approaches of psychotherapy. Behaviorism, and the Cognitive-Behavioral school of thought, as well as Client-centered (Humanistic) therapy, and Family Systems therapies joined Psychodynamic psychotherapy as popular treatment options. We will discuss these psychological theories, including what they have to say about the causes of and treatments for depression in more detail in a later section of this document.
Currently, rather than adopting either the mind or the body explanation of depression, scientists and mental health practitioners recognize that depressive symptoms have multiple causes. In other words, in the current view, depression can be caused by both mental and physical causes at the same time. It is no longer necessary to choose a single cause, as no single cause is going to be sufficient to explain and account for all varieties of depression. Because it has become the accepted view that depression frequently has multiple causes, including biological, psychological and social causes, it has also become the norm that multiple professions and approaches to treatment have important roles to play in helping people overcome depression.