Beyond the ability of the individual to carry out daily activities, there is the issue of quality of life. So a person who can get up and go to work but finds no pleasure in normal activities is someone whose symptoms still merit concern from the mental health professional (Hood & Johnson, 2006, pp. 27-9.) Psychiatrists: The Medical Model of Treatment

For many people the most obvious professional to seek treatment from when faced with the symptoms of mental disorders is a psychiatrist. (Maybe because we've grown up reading the psychiatry cartoons in The New Yorker!) Psychiatrists are medical doctors and so their basic response to the symptoms of mental disorders will tend to be a medical one. This encompasses an overall examination of the person's health. (For example, a psychiatrist might run a series of thyroid function tests to determine if a patient's depressive symptoms were related to thyroid problems rather than another underlying issue.) A psychiatrist would also consider underlying biochemical reasons for a person's symptoms. For example, if a patient reported symptoms of depression, a psychiatrist would certainly at least consider prescribing an anti-depressant such as Cymbalta or Effexor. If a patient reported high levels of anxiety, a psychiatrist might prescribe an anti-anxiety drug such as Xanax. And if a patient reported obsessive or compulsive tendencies then a psychiatrist might prescribe a medication that helps remedy such impulses such as Paxil.

Psychiatrists should -- although they do not always succeed at this -- consider the entire set of circumstances of a patient's life, as this description makes clear:

Psychiatry is a branch of medicine: it deals with those disorders in which mental (emotional or cognitive) or behavioural features are most prominent. The cause, presentation, and course of such disorders are influenced by diverse factors; their symptoms can be bewildering to patients and their relatives; and their management may require social and psychological as well as medical interventions. It is not surprising that this complex situation can lead to misunderstandings of the role of psychiatrists (who are neither social workers nor jailers) and myths about the practice of psychiatry. (Davies 1997, p. 314).

Psychiatrists are (or at least generally are) given training in the central therapeutic techniques such as empathy. However, many psychiatrists do not find a traditional therapeutic approach to be comfortable and so may essentially outsource this aspect of treatment to another type of clinician in the field, such as a therapist (Suzuki & Ponterotto, 2007, p. 41).

Marriage and Family Therapy

Marriage and family therapists (the term varies to some extent from state to state and has changed over time) have master's degrees in counseling or psychology or a related field. Their focus on a client is the person's relationship to others as well as to herself or himself. Because the focus of therapy is to improve the individual's relationships, assessments on the part of the therapist will focus on symptoms and feelings that interfere with healthy relationships (Suzuki & Ponterotto, 2007, p. 119). So, for example, if a client reports that he is unable...

After the client had a better sense of insight into the origins of his behavior, the client and the therapist would work together to change the client's behavior towards others (which might take the form of cognitive behavioral therapy).
Both therapists and psychiatrists depend on the same basic parameters for diagnosis -- The Diagnostic and Statistical Manual in its current form (the revised fourth edition at the moment, with the fifth edition on the horizon). Both professions agree in general on what constitutes a mental disorder but vary in their understanding of the origins and best treatments for these disorders (Groth-Marnat, 2009, p. 81).

Social Workers

Social workers are also responsible for assessing and designing treatment plans for clients with mental disorders. However, as their title suggests, their approach is somewhat different. While psychiatrists tend to look first to medical reasons and possible treatments for mental disorders and therapists tend to look to relationship issues as being fundamental, social workers are trained to look first to the pragmatic elements of the individual's life. Social workers (who hold master's degrees in social work or a related field) tend to look first to issues like providing adequate housing, schooling, and nutrition to an individual and her or his family than to the biochemical nature of disease or long-term attachment issues (for example).

HIPPA

Ideally, most individuals with a mental disorder could benefit from a range of services, including therapy to look at problems in relationships, a general doctor to assess overall health, a psychiatrist to prescribe psychoactive drugs when needed, and a social worker to help with problems with everyday life. To this end, HIPPA -- the federal act that requires significant protections for a patient's or client's rights -- may actually interfere with the provision of the kind of intersection of a variety of services that most individual needs. As health professionals become increasingly wary of potential violations of HIPPA (not that confidentiality is not important, but sharing of information among a team of professionals working with an individual is also important) there well may be less sharing of the kind of information that would help those facing the immense challenges of mental illness (Suzuki & Ponterotto, 2007, p. 245).

References

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR Fourth Edition.

Davies, T. (1997, 24 May.). ABC of mental health: Mental health assessment. BMJ: 314.

Groth-Marnat, G. (2009). Handbook of psychological assessment. New York: Wiley.

Hood, A. & Johnson, R. (2006). Assessment in counseling: A guide to the use of psychological procedures. Washington DC: American Counseling Association.

Suzuki, L. & Ponterotto, J.G. (eds.) (2007). Handbook of Multicultural Assessment: Clinical, Psychological, and Educational Applications, London: Jossey-Bass.