2.1. Participants
Thirteen patients with BPD referring to clinics and psychiatric wards of Iran University of medical sciences were recruited. The diagnosis was based on a Structured Clinical Interview for Diagnostic-II (SCID-II) by trained examiners. Patients younger than 18-years-old, or older than 90-years-old were excluded as were patients with a major neurological disorder such as epilepsy, traumatic brain injury, comorbidity with antisocial personality disorder, substance use disorder during the year of study, alcohol or cannabis intoxication, major mood disorder, psychotic disorder, education lower than high school. To be enrolled in the study, patients were required to be stable on their medications for at least one month before recruiting. Participants entered the study after they were fully informed about the one-year duration and the research purpose and completed an informed consent. Four participants dropped out during one year of psychotherapy and they were excluded from the analyses. Nine healthy participants younger than 18-years-old, or older than 90-years-old were excluded as were patients with a major neurological disorder such as epilepsy, traumatic brain injury, comorbidity with antisocial personality disorder, substance use disorder during the year of study, alcohol or cannabis intoxication, major mood disorder, psychotic disorder, education lower than high school. All the research was approved by the ethical committee of the Iran University of Medical Sciences (Ethical code: IR.IUMS.REC.1398.872) and informed consent was taken from all the participants. All methods were performed in accordance with the relevant guidelines and regulations of Helsinki.
2.2. Instruments
2.2.1. Structured Clinical Interview for Diagnostic-I (SCID I)
This is a semi-structured interview for examination of major axis I psychiatric disorders based on DSM IV criteria. Its reliability and validity in the Persian translation has been established and it’s test-retest reliability is fair to good 2021222324.
2.2.2. Structured Clinical Interview for Diagnostic II (SCID II)
The Structured Clinical Interview for Diagnostic-II (SCID-II), carried out as a semi-clinical structured interview, is conducted to diagnose personality disorders based on the DSM IV. The SCID-II shows adequate interrater reliability (from .48 to .98) and good reliability for dimensional diagnosis (from .90 to .98) and internal consistency (.71-.98). The SCID-II questionnaire was translated into Persian but its psychometric investigation is somewhat limited. In one study, the Persion SCID II test-retest reliability was reported at 0.87 25.
2.2.3. The Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST)
This scale was first developed to evaluate a wide range of substance use and consequent problems in primary care patients. The ASSIST items were considered easy to answer and were found to be reliable and feasible to administer in an international study. The test-retest reliability coefficients ranged from 0.58 to 0.9. The reliability range for different categories of substances averaged 0.61 for sedatives to 0.78 for opioids2627.
2.2.4. Borderline evaluation of severity over time questionnaire (BEST)
This is a self-report measure that assesses the change and severity of BPD, such as thoughts, feelings, and negative actions over time. It includes 15 items and three subscales on the Likert-like Range 28. Its reliability and validity have been studied in Persian 29.
2.2.5. Interpersonal Reactive Index (IRI)
The IRI is a self-report questionnaire. It assesses four dimensions of empathy, and each subscale (empathic concern, perspective-taking, personal distress, and fantasy) is made up of 7 items.
Participants rate how much an item will describe them on a 5-point Likert scale. (does not describe me well = 0 to represent me very well = 4). The maximum and minimum total scores on this questionnaire are 28 and 0, respectively. This questionnaire has shown relatively good psychometrics with high internal consistency (Alfa Cronbach of 0.68 to 0.79 (Davis, 1983), good reliability for both cognitive (alpha = 0.654) and emotional empathy (alpha = 0.767). Cronbach's Alpha of each subscale ranges between 0.7 to 0.77 (Davis, 1994). Test-retest reliability was reported within 0.62 to 0.8 303132. This questionnaire has been translated into Persian and it’s psychometric properties have been studied extensively 33.
2.2.6. Toronto Alexithymia Scale-20 (TAS-20)
This questionnaire evaluates four dimensions of emotional awareness, including difficulty identifying the feeling, difficulty describing feelings, and externally oriented thinking. Its validity and reliability have been studied by Bagby and et al 34 and has shown fairly good reliability and validity in Persian 353637.
2.3. Psychotherapy
Once weekly, patients had a session of therapeutic session emphasizing the Transference Focused Psychotherapy approach. The content of the session was written by the therapist every week. The patient's progression through the year was noted and analyzed. Core concepts of transference and countertransference, defense mechanisms, and signs of emotional communication were highlighted. Each therapist had an individual supervisor. In addition, monthly group supervisory sessions were held to work through the dynamics of the sessions and feelings of being part of a study.
2.4. Procedure
Participants were recruited by convenience sampling among patients referred to clinics and psychiatric wards of the Iran University of Medical Sciences. Those who meet inclusion criteria based on the SCID II interview entered the study. After completing the informed consent, participants filled out the demographic questionnaire, IRI, TAS 20, ASSIST, BEST questionnaire. Then their default mode network connectivity was measured using resting-state fMRI before initiating psychodynamic psychotherapy. After starting psychodynamic psychotherapy, DMN connections were assessed 3 more times with each assessment separated by approximately 4 months (so that including their baseline assessment, the total number of fMRI assessments for each individual was 4). Finally, at the conclusion of their therapy patients again completed the IRI, TAS 20, ASSIST, the BEST questionnaire to monitor any possible changes.
2.5. fMRI acquisition
Multimodal MRI data were collected in a Siemens magnetom Prisma 3T MRI scanner. The resting-state functional MRI images covering the whole brain were obtained with an echo-planar imaging sequence with the following parameters: 240 volumes (8 min and 6 s), axial slices = 32 slices with 3.5 mm thickness, repetition time (TR) = 2000 ms, echo time (TE) = 30 ms, flip angle (FA) = = 90°, voxel size: 3.1×3.1×3.5 mm, the field of view = 200×200 mm, and matrix size = of 64 × 64. T1-weighted structural images were acquired for co-registration of functional images using a sagittal 3D-magnetization prepared rapid acquisition gradient echo (MPRAGE) sequence: TR 1800 ms, TE = 3.53 ms, inversion time(TI) = 1100 ms, FA = 7°, FOV = 256 × 256 mm2, matrix size = 256 × 256, slice thickness = 1 mm, and scan time = 4min and 12 s.
2.6. fMRI Analysis
The analyses consist of five sequential steps that included pre-processing, extracting DMN FC matrix (FCM) based on the automated anatomical labeling (AAL) atlas, thresholding, and binary FCM, constructing binary graph network from binary FCM and extracting graph-theoretical features, and finally comparison and statistical analyses.
2.6.1. Preprocessing
For each subject, Preprocessing of the rs-fMRI data was carried out using statistical parametric mapping (SPM12) and the data processing assistant for resting-state fMRI (DPARSF) toolbox version 4.5 38. Briefly, the following steps were carried out: 1) removing the first 10 volumes of the 240 volumes to allow for magnetization equilibrium; 2) Skull stripping was performed on both functional and structural images to remove non-brain tissue before co-registration of T1 images and functional images for better registration of T1 image to functional space; 3) slice-timing correction; 4) correcting for head movements, which required the images to be realigned with a six-parameter (rigid body) linear transformation. Individual structural images were co-registered to mean functional images; 5) segmentation of T1-weighted images into grey matter (GM), white matter (WM), and cerebrospinal fluid (CSF); 6) regressing out of 27 nuisance covariates, including signals from WM and, CSF, global signals, and Friston 24 motion parameters; 7) Spatial normalization was done to the standard template Montreal Neurological Institute (MNI) space; 8) Spatial smoothening with a Gaussian kernel of 6 mm full-width at half-maximum (FWHM_); and 9) Subsequently, a temporal band pass filter (0.01–0.01Hz) was performed to reduce the influence of low-frequency drift and high frequency respiratory and cardiac noise.
2.6.2. Brain functional connectivity matrix (FCM) and Graph construction
For analysis of FC, the seed regions of the default mode network(DMN) were chosen based on a priori knowledge 3940 from the AAL atlas 41 with the DMN regions shown in Table 1. The time series for each region were extracted and then on each pair, the Pearson correlation was used to obtain a correlation matrix for each participant. Based on the correlation matrices, we constructed a weighted brain graph or weighted functional connectivity matrix by using a set of sparsity thresholds ranging from 5–40% with a step of 1% (5 ≤ T ≤ 40). The sparsity threshold represented the proportion of the present connections to the maximum possible connections within the network. This approach included assigning labels 1 to D% (density) of the strongest connections in each network and 0 to other connections. 42. For group comparison, unlike the absolute threshold, the use of proportional thresholds ensures that the network of each group have the same number of nodes and edges42. This makes more meaningful comparisons between the two groups. We described FC with a network density of 5–40%. The Range of 5–40% was chosen for interpretation, because, according to previous reports, this range is in overall consistency with the biological background of the brain functional networks 4344.
Table 1
Regions of interest default mode network (DMN).
DMN Regions (or nodes)
|
Abbreviation
|
Left and right Superior frontal gyrus, orbital part
|
ORBsub.L, ORBsub.R
|
Left and right Middle frontal gyrus
|
MFG.L, MFG.R
|
Left and right Inferior frontal gyrus, orbital part
|
ORBinf.L, ORBinf.R
|
Left and right Superior frontal gyrus, medial
|
SFGmed.L, SFGmed.R
|
Left and right Superior orbital frontal gyrus, medial
|
ORBsupmed.L,ORBsupmed.R
|
Left and right Anterior cingulate and Paracingulate gyri
|
ACG.L, ACG.R
|
Left and right Median cingulate and Paracingulate gyri
|
DCG.L, DCG.R
|
Left and right Posterior cingulate gyrus
|
PCG.L, PCG.R
|
Left and right Hippocampus
|
HIP.L, HIP.R
|
Left and right Parahippocampal gyrus
|
PHG.L, PHG.R
|
Left and right Inferior parietal lobule
|
IPL.L, IPL.R
|
Left and right Angular gyrus
|
ANG.L, ANG.R
|
Left and right Precuneus
|
PCUN.L, PCUN.R
|
Left and right Middle temporal gyrus
|
MTG.L, MTG.R
|
Left and right Temporal gyrus pole: middle temporal
|
TPOmid.L, TPOmid.R
|
Left and right Inferior temporal gyrus
|
ITG.L, ITG.R
|
2.6.3. Graph-theoretical measures
Centrality metrics can determine the importance of each node in a brain network, which makes them appropriate measures to capture the complexity of functional connectivity. Among these metrics, the nodal degree is the most popular measure of centrality since it is directly related to functional connectivity 454647. Furthermore, the nodal degree is shown to have a high correlation with other centrality metrics (betweenness centrality, clustering coefficient, node neighbor's degree, and closeness centrality) 45484950. We calculated the ‘nodal degree’ in DMN regions and compared patients with BPD with the healthy control group.
The ‘nodal degree’ of each node equals the total number of edges that are connected to a node 51 46.

where N is the number of all nodes in the network, aij is the connection value between a pair of nodes (i and j), with aij = 1 when a connection between (i, j) exists, and aij = 0 unless otherwise.
2.6.4. Statistical analyses
A nonparametric permutation test with 10000 resamples was used to evaluate the significance of differences in degree between the HC and BPD groups. The nonparametric permutation test is used to determine whether a measured effect is genuine or is a statistical anomaly due to the randomness associated with the selection of the sample 52. Permutation testing for controlling the nominal type I error is considered acceptable 52. We also used a non-parametric permutation test to assess the significance of the differences between groups (reported as p-values) and to determine the 95% confidence intervals 53.
2.7. Association of nodal degree results with clinical measurements
To determine the relationship between nodal degree results and clinical variables, Pearson correlation coefficients were calculated using SPSS 25 (SPSS Inc; Chicago, Illinois). The clinical variables included the empathy, assist, TAS, and best measures. Also, we used paired t-tests to evaluate differences between pre-and post- psychotherapy clinical evaluations.