Biological treatments for mental disorders are in the ascendance because of research findings on the genetic and biological causes of some disorders and because of economic and social factors. The medications most commonly prescribed for mental disorders include antipsychotic drugs, antidepressants, tranquilizers, and lithium carbonate. Drawbacks of drug treatment include the placebo effect; high dropout and relapse rates among people who take medications without also learning how to cope with their problems; the difficulty of finding the correct dose for each individual; and the long-term risks of medication and of possible drug interactions when several are being taken. Medication should not be prescribed uncritically and routinely, especially when psychological therapies can work as well for many mood and behavioral problems.

When drugs and psychotherapy have failed to help seriously disturbed people, some psychiatrists have intervened directly in the brain (psychosurgery). Prefrontal lobotomy never had any scientific validation, yet was performed on many thousands of people. Electroconvulsive therapy(ECT), has been used successfully to treat acute episodes of suicidal depression, although its benefits rarely last. A newer method, transcranial magnetic stimulation(TMS), is being studied as a way of treating severe depression. Deep brain stimulation(DBS) requires the surgical implantation of electrodes and a stimulation device.

Psychodynamic (“depth”) therapies include Freudian psychoanalysis and its modern variations, such as approaches based on object-relations theory. These therapies explore unconscious dynamics by focusing on the process of transference to break through the patient’s defenses and by examining childhood issues and past experiences.

Behavior therapists draw on classical and operant principles of learning. They use such methods as graduated exposure and flooding; systematic desensitization; behavioral self-monitoring; and skills training. Cognitive therapists aim to change the irrational thoughts involved in negative emotions and self-defeating actions. Aaron Beck’s cognitive therapy and Albert Ellis’s rational emotive behavior therapy(REBT) are two leading approaches. Cognitive-behavioral therapy(CBT) is now the most common approach.

Humanist therapy holds that human nature is essentially good and attempts to help people feel better about themselves by focusing on here-and-now issues and on their capacity for change. Carl Rogers’s client-centered (nondirective) therapy emphasizes the importance of the therapist’s empathy and ability to provide unconditional positive regard. Existential therapy helps people cope with the dilemmas of existence, such as the meaning of life and the fear of death.

Family therapies are based on the view that individual problems develop in the context of the whole family. They share a family-systems perspective, the understanding that any one person’s behavior in the family affects everyone else. In couples therapy, the therapist usually sees both partners in a relationship.

Successful therapy often requires a therapeutic alliance between the therapist and the client, so that they understand each other and can work together. A scientist–practitioner gap has developed because researchers and many clinicians hold different assumptions about the value of empirical research for doing psychotherapy and for assessing its effectiveness. In assessing the effectiveness of psychotherapy, researchers need to control for the placebo effect and the justification of effort effect. They rely on randomized controlled trials to determine which therapies are empirically supported.

Some psychotherapies are better than others for specific problems. Behavior therapy and cognitive-behavioral therapy are often the most effective for depression, anxiety disorders, anger problems, certain health problems (such as pain, insomnia, and eating disorders), and childhood and adolescent behavior problems. Family-systems therapies, especially when combined with behavioral techniques as in multisystemic therapy, are especially helpful for children, young adults with schizophrenia, and aggressive adolescents. The length of time needed for successful therapy depends on the problem and the individual. Some methods, such as motivational interviewing, produce benefits in only a session or two; long-term psychodynamic therapy can be helpful for people with severe disorders and personality problems.

In some cases, therapy is harmful. The therapist may use empirically unsupported and potentially harmful techniques, such as “rebirthing”; inadvertently create new disorders in the client through undue influence or suggestion; hold a prejudice about the client’s gender, ethnicity, religion, or sexual orientation; or behave unethically, for example by permitting a sexual relationship with the client.