Only some gender-nonconforming people experience gender dysphoria at some point in their lives".
Gender nonconformity is not the same as gender dysphoria; nonconformity, according to the standards of care, is not a pathology and does not require medical treatment. In cases of comorbid psychopathology, the standards are to first manage the psychopathology and then evaluate the patient's gender dysphoria.
The requirements for chest reconstruction surgery are different for transmen and transwomen.
In appropriately evaluated cases of severe gender dysphoria, sex reassignment therapy is often the best when standards of care are followed. While the diagnosis is a requirement for determining medical necessity of sex reassignment therapy, some people who are validly diagnosed have no desire for all or some parts of sex reassignment therapy, particularly genital reassignment surgery, and/or are not appropriate candidates for such treatment.
There is academic concern over the low quality of the evidence supporting the efficacy of sex reassignment therapy as treatment for gender dysphoria, but more robust studies are impractical to carry out; as well, there exists a broad clinical consensus, supplementing the academic research, that supports the effectiveness in terms of subjective improvement of sex reassignment therapy in appropriately selected patients. The general standard for diagnosing, as well as treating, gender dysphoria is outlined in the WPATH Standards of Care for the Health of Transsexual, Transgender, and Gender Nonconforming People.
Often, at least a certain period of psychological counseling is required before initiating hormone replacement therapy, as is a period of living in the desired gender role, if possible, to ensure that they can psychologically function in that life-role.
On the other hand, some clinics provide hormone therapy based on informed consent alone.
Treatment may still be appropriate and necessary in cases of significant comorbid psychopathology, as "cases have been reported in which the individual was both suffering from severe co-occurring psychopathology, and was a 'late-onset, gynephilic' trans woman, and yet experienced a long-term, positive outcome with hormonal and surgical gender transition." However, some transsexual people may suffer from co-morbid psychiatric conditions unrelated to their gender dysphoria.