Participants
The sample consists of 131 individuals, 58 of whom belong to the general population sample, and 73 to a mixed clinical sample. Within the mixed clinical sample, 38 patients have an ICD-10 diagnosis of a mood and/or anxiety disorder, and 28 patients have an ICD-10 diagnosis of a personality disorder. Within the mood/anxiety disorder group the majority of participants have the ICD-10 diagnosis of either major depressive disorder, single episode, moderate (F32.1; 10 participants, 26%); mixed anxiety and depressive disorder (F41.2; 10 participants, 26%); or recurrent depressive disorder, moderate, without psychotic symptoms (F33.2; 9 participants, 24%). Within the personality disorder group 13 patients (46%) have a diagnosis of personality disorder not specified (F60.9), 12 (43%) have a diagnosis of borderline personality disorder (F60.31), and 3 (11%) have the diagnosis of mixed type personality disorder (F61). Diagnoses were assigned by their treating psychiatrist based on clinical assessment.
Participants' ages range from 15 to 75, 19% of participants are 19 years or younger, 20% are between 20–25 years old, 19% between 26–30 years old, 21% between 31–39 years old, 9% between 40–49 years old, and 12% over the age of 50. In the total sample, 17% of the participants have obtained primary education, 16% secondary education, 8% vocational education, and 28% have a university degree.
There are slight demographic differences between the general population and the mixed clinical population. The ratio of male participants in the general population sample is 57% as compared to 26% male in the clinical sample.
There are differences in education, with 36% of the general population sample having obtained a university degree, compared to 22% in the clinical sample. Furthermore, 29% of the clinical sample has primary education as their highest attained education, compared to 3% in the general population. This is at least partially due to the fact that the clinical sample is significantly younger than the general population sample. 73% of the clinical sample is younger than 30 years old, as compared to 41% under 30 in the general population.
The sample demographic differences reflect real life differences, at least to a certain degree. Research indicates that females tend to seek more medical care than males [20], and symptoms of personality dysfunction are often most prevalent and disturbing in young adulthood, often subsiding in their natural course with age [14].
Participants in both the general population and patient sample were recruited using snowball methodology by the participants who took part in the STiP-5.1 interview training. Patient status was not recorded—the sample includes both inpatient and outpatient participants.
Instruments
Semi-structured interview for Personality functioning DSM-5 (STiP-5.1)
The STiP-5.1 [18] is a clinician-rated semi-structured interview for the assessment of overall personality functioning. The interview results in a general personality functioning score and two main domains of self and interpersonal functioning that each have two elements: self functioning consists of identity and self-direction, and interpersonal functioning of empathy and intimacy. Clinicians rate all of these aspects of functioning on a scale of 0 (no impairment) to 4 (extreme impairment). The administration takes on average 50 min in the original version, ranging from 28 to 70 min.
Previous versions of the STiP-5.1 have shown good internal consistency with Cronbach ɑ of 0.97 for the original scale, and interrater reliability of ICC = 0.93 for the German version.
The interviewers in this study were either trained by the author of the original version (J. Hutsebaut) during a 1 day workshop or trained by participants of this workshop who had used the STiP-5.1 in clinical practice for more than 2 years. The latter training included 4 times 4 h workshops where theoretical background of the instrument was given, and the interview process and scoring was practiced. The study interviews were conducted after the participants had practiced carrying out the interview under supervision and had scored an interview example. The interview length in this study was generally 60 min or more, since the participants were encouraged to ask for examples and use the additional questions to improve their scoring accuracy.
The Level of Personality Functioning Scale–Brief Form (LPFS-BF 2.0)
The LPFS-BF 2.0 [7] is a brief self-report version of the original Level of Personality Functioning scale [9]. The LPFS–BF was initially constructed and empirically evaluated in Dutch, and subsequently translated to English [19]. The scale consists of 12 items related to dysfunction in identity, self-direction, empathy and intimacy, each rated on a 4-point Likert scale (from 0 = very false or often false to 3 = very true or often true). The scale results in one global dimension score that can be interpreted as overall personality dysfunction.
With the author’s permission the scale was translated into the Estonian language, and tested out in both general population and patient samples with participants being able to give feedback on scale items. It was then overviewed by two clinical psychologists, and translated back into the English language to ensure sufficient similarity to the original scale.
The preliminary Estonian version of the LPFS demonstrates adequate psychometric properties. Exploratory factor analysis suggests a one factor solution, with confirmatory factor analysis fit indices for this model being χ2(54) = 137, p < .001; CFI = .83, TLI = .70, RMSEA = .13, SRMR = .09. Fit indices are in the same range, if slightly higher for the two factor model (χ2(53) = 107, p < .001; CFI = .89, TLI = .86, RMSEA = .11, SRMR = .07), resulting in two interpretable subscales of self and interpersonal functioning, similar to the original version [19]. Total scale reliability is high with McDonald’s ω = .91, and the subscales are also internally consistent: Self functioning ω = .88, and Interpersonal functioning ω = .82.