The Minnesota Multiphasic Personality Inventory, developed in its first version in the late 1930s by Hathaway and Mc Kinley, and published in 1940, and its successor MMPI-2 of 1989, by Butcher, Dahlstrom, Graham, Tellegen, is certainly the most widely used structured personality questionnaire in the world, adopted in at least 45 countries, with a bibliography of thousands of titles and a solid empirical basis.
The 1989 version includes 567 items expressed as statements about oneself, covering attitudes, interests, psychological characteristics, habits, beliefs, somatic complaints, aspirations, general considerations to be initialed by the subject as True or False, or ‘I don’t know,’ selected from more than a thousand items from which redundant or insignificant ones were eliminated, standardized, for the U.S. edition, on a sample of 2300 subjects very representative of the entire U.S. population,
The different groupings of items allow for the construction of thirteen basic scales: three validity scales, L (lying), F (infrequency), and K (correction) and 10 clinical scales, Hypochondria -Hs or scale (1), Depression-D or scale (2), Hysteria -Hy or (3), Psychopathic deviance -Pd o (4), Masculinity-Femininity -Mf o (5), Paranoia -Pa (6), Psicasthenia -Pt o (7), Schizophrenia -Sc o (8), Hypomania -Ma o(9) and Social Introversion -Si o (0)).
In addition, fifteen additional scales are distinguished, including three new control scales, Back F or FB (infrequency in the last part of the protocol, beyond item 370), VRIN and TRIN (respectively, inconsistency in responses in general, and inconsistency in ‘True’ responses), twelve scales related to specific problems (e.g., A- Anxiety, R- Repression, O-H- Hypercontrolled Hostility, MAC R- Revised Mac Andrew’s Alcoholism Scale, PK and PS, indices of Post Traumatic Stress Disorder) and fifteen content scales, grouping similar areas (e.g., ANX-Anxiety, FRS-Phobias, HEA-Health Problems, LSE-Low Self-Esteem, FAM-Family Problems).
The procedure for constructing each basic scale was strictly empirical: for each clinical scale, a group of items was chosen to which the group used as criteria for that specific pathological feature (selected with patients diagnosed with a single disorder so as to avoid diagnostic overlap) responded very differently from the control group of normal subjects.
The raw scores obtained for each scale are converted to linear T-scores through the application of a formula that takes into account the mean and standard deviation of the raw scores for each normative group. The scores of some clinical scales are transformed into K-corrected linear T-scores, taking into account the subject’s defensive attitude as expressed by the K-scale.
To better define and specify the elevation of each clinical scale, subscales have been developed (Harris and Lingoes, 1968) to better discriminate which specific psychological variables cause the scale to be elevated: for example, the D (Depression) scale may be elevated due to several factors: D1-Subjective depression, D2-Psychomotor slowing, D3-Physical dysfunction, D4-Mental inefficiency, D5-Rimugitation, while the Pa (Paranoia) scale may have elevation due to factors described by the subscales Pa1-Persecutory ideation, Pa2-Susceptibility, Pa3-Ingenuity.
Two lists of Critical Items were also developed, Koss and Butcher’s Critical Items and Lachar and Wrobel’s Critical Items, which identify specific problems: for example, suicidal depressive ideation or acute anxiety state or persecutory ideas among the former, and poorly controlled anger Deviant thoughts and experiences, Sleep disorders among the others.
Once the protocol has been recognized as valid and reliable, through the dedicated scales, the analysis continues with interpretation using coding interpretation (where a significant elevation of one or two scales relative to the rest of the profile emerges), then articulated by comparison of the actual scores reported by the subject and the average scores reported by subjects with the same codetype: significant discrepancies and peculiarities of responses are analyzed; the elevation of clinical scales is better specified through interpretation of the relevant subscales, and of the supplementary and content scales. If, on the other hand, no definite code can be identified, interpretation directly analyzes the various scales: clinical, supplementary, content.
A very useful and interesting tool, developed by Green and Nichols , is the Structural Summary, which groups the different indices derived from the protocol into meaningful clusters (modeled after the Structural Summary of the Comprehensive System for the Rorschach test), so as to avoid overlap and redundancy, and to organize the data, so as to facilitate an interpretation by areas: Attendance, Mood, Cognitive Activity, Interpersonal Relations, Other Areas.
A real revolution in test interpretation is that introduced by the brilliant U.S. scholar Alex Cadwell and in his wake by other authors (Levak, Friedman, Finn) who have foregrounded the centrality of the patient and the interpretation of the different codetypes and typical profiles as expressions of specific modes of adaptation-more or less successful or maladaptive-of the person to certain types of trauma or nonspecific difficulties in the developmental age.
This very innovative reading thus uses the analysis of scales and their traditional groupings to go beyond the very impersonal classic ‘descriptors’ employed by the more classical, sometimes veiledly ‘judgmental’ authors, arriving at an empathetic and sympathetic type of description of the subject in his or her mechanisms of adaptation to traumatic events and defense mechanisms.