Diagnostic assessment is the process of appraising a patient's condition. It involves effectively engaging the patient in order to obtain accurate information relevant to understanding health problems (mental and general medical disorders), their context (psychosocial and environmental problems) and their impact on adaptive functioning and participation in society (disablements). A comprehensive diagnostic formulation represents a summary of the clinician's judgement about the overall condition of the patient, obtained as much as possible with the latter's collaboration. The main purpose of diagnosis is to serve as the basis for clinical care. Further objectives include to communicate concisely and reliably information on health problems, to understand their biopsychosocial pathogenesis and the interaction of internal and contextual factors, to enhance training and research, and – last but not least – to inform a collaborative process of care aimed at the restoration and promotion of health, functioning and quality of life (Fig. 1.1).

An appropriate setting for the psychiatric interview should be selected or arranged within the circumstances available. It should be as comfortable as possible for both patient and interviewer, protect privacy, and minimise external distractions.

The use of extended sources of information is an important part of the diagnostic process, since they corroborate, complement or correct information provided by the patients themselves.

All patients presenting for psychiatric care should receive a comprehensive descriptive psychopathological evaluation. This should include a broad symptomatological assessment specifying the time frames of the findings, as well as a mental state examination at the time of the patient interview (Table 4.1).

Supplementary assessment procedures may be used to complement the psychiatric diagnostic interview. These include procedures for the comprehensive evaluation of the mental and physical state of the patient (psychosocial procedures are considered in part 6 (IGDA Workgroup, WPA 2003, this suppl.)). Psychopathological assessment instruments, biological tests and procedures and neuropsychological tests are among those used to enrich or refine data collected in a clinical interview in order to arrive at the standardised multi-axial diagnostic formulation.

Supplementary procedures (Fig. 6.1) can be used to obtain a comprehensive assessment of social, cultural and other contextual factors influencing the occurrence, presentation, course or treatment of clinical disorders. They may also be useful for measuring social and occupational functioning and participation, social support, family adjustment, life events and quality of life. In these, as in all clinical assessments, the cultural framework should be systematically considered.

A thorough and systematic assessment of a patient should lead to a comprehensive diagnostic statement. The first component of this is the multi-axial diagnostic formulation.

The diagnostic process involves more than simply identifying a disorder or distinguishing one disorder from another. It should lead to a thorough, contextualised and interactive understanding of a clinical condition and of the wholeness of the person who presents for evaluation and care.

Clinical care starts with the first diagnostic interview. Therapeutic planning and prognosis should be based on competently conducted and documented comprehensive diagnosis, i.e. a standardised multi-axial formulation covering clinical disorders, disabilities, contextual problems and quality of life, as well as an idiographic or personalised formulation articulating the perspectives of the clinician with those of the patient and family on contextualised clinical problems, the patient's positive factors, and expectations about restoration and promotion of health.

A systematic record of information collected during the process of diagnosis and care is essential to document understanding of the patient's mental, physical and social condition and the clinical service provided (Fig. 10.1).

Ms Y is a 28-year-old monolingual Spanish-speaking woman of Mexican origin living for 2 years in the USA and married to a Mexican man self-employed in the construction business. She presents for care to the emergency room accompanied by a female friend, complaining of ‘nervios’, feeling guilty for not being able to perform her duties as a wife, and concerned that there may be some type of imbalance in her body. The interviewer is a female psychiatrist, born in South America and trained in the USA.