Information the psychiatrist should gather before interviewing the subject includes past hospital discharge summaries, certain psychological test reports, earlier presentence reports by a probation officer, records of confession, letters written by the defendant, and supporting materials from friends, relatives, and other attorneys. During the interview itself, the psychiatrist can collect data based on the subject's language use, ideation, and affective states. Things to note in language use are tendencies for words to 'pour out,' evasiveness, semantic vagueness, 'blocking' in the middle of certain thoughts, loudness or softness associated with certain topics, neologisms, and incoherence. In ideation, the psychiatrist should note the recurrence and predominance of certain topics and be sensitive to statements that suggest hallucinations. Affective states may be determined from the subject's verbalizing his/her emotional state, or the state may be observed from the patient's mannerisms and behavior. In terms of the standards used to evaluate the data collected, there is substantial consensus on the nomenclature used for classification and diagnosis expressed in the standard nomenclature of the American Psychiatric Association. Certainty, however, is not to be expected from the psychiatrist. Useful generalizations are all that can be realistically expected. Twenty footnotes are provided. (Editor summary modified)