The Ghent Psychotherapy Study (GPS)

Current primary outcome measures as of 01/10/2015:
Baseline and post-treatment severity of depression symptoms is derived by the Dutch version of the Hamilton Rating Scale for Depression (HDRS). Two external raters are trained to reach adequate interrater-reliability. The raters are blind to the research hypotheses, the research design, and the conditions to which the patients were assigned. The HDRS is rated on semi-structured pre- and post interviews (adjusted SCID-I for baseline severity and HDRS interview for post-treatment severity; see above and below) that are rated in random order, in order to avoid expectancy biases.

Previous primary outcome measures:
The Beck Depression Inventory-II, Dutch version (BDI-II-NL) is a symptom-specific questionnaire with 21 self-rated items, which indicates the severity of symptom of Major Depressive Disorder. It will be administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.

Current secondary outcome measures as of 01/10/2015:
1. The Beck Depression Inventory-II, Dutch version (BDI-II-NL) is a symptom-specific questionnaire with 21 self-rated items, which indicates the severity of symptoms of Major Depressive Disorder. It will be administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
2. The Inventory of Interpersonal Problems-32 (IIP-32) is a self-rated questionnaire with 32 items that indicates the most salient interpersonal problems. It is administered pre-treatment and posttreatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
3. The Symptom Checklist-90-Revised (SCL-90-R) is a self-rated questionnaire with 90 items that indicates a range of psychopathology symptoms. It is administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
4. Outcome Questionnaire-45 (OQ-45) is a self-rated questionnaire with 45 items that indicates general wellbeing. It is administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
5. The shortened Depression Anxiety and Stress Scale (DASS) is a 21-item self-report questionnaire on the presence and severity of symptoms of depression, anxiety and stress. It is administered pretreatment and post-treatment, at every session of the treatment process, and at 3-month, 6-month, 12-month and 24-month follow-up.
6. Cortisol stress levels are analyzed as indicators of stress, by means of mass spectrometry of saliva and hair samples. The saliva samples are gathered for four consecutive days (one sample early morning and one late evening every day) at pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up. The hair-samples are gathered at pre-treatment, peri-treatment and post-treatment and at 6-month and 24-month follow-up.
7. Cost-efficiency by means of health-care cost information is retrieved via the Inter-mutualistic Agency (http://www.nic-ima.be), covering a period starting 3 years pretreatment until 2 years post-treatment. This is one of the only ways to gather objective information on a longer period before the patient enters therapy; and it can be used to get a clear picture of antidepressant medication use.

Process Measures / Clinical Predictors
1. The Client Change Interview (CCI) is a semi-structured interview focused at patient experience of the process of change during and following the treatment process. It is administered around the 12th treatment session, at post treatment and at 6-month and 24-month follow-up.
2. An idiosyncratic complaint is formulated at the onset of treatment, and rated by the patient on a continuous scoring line (the far left end indicates absence of the complaint, the far right end indicates full presence and severe suffering from the complaint). It is rated retrospectively for the week before each treatment session.
3. Medication use changes are indicated at every treatment session.
4. The Emotion Checklist is a visual analogous scale (VAS) with ten scales on which the current emotional state is rated before every treatment session.
5. The Working Alliance Inventory (WAI) is a 12-item questionnaire focused on the working alliance between the therapist and the patient as experienced during the treatment session. The questionnaire is completed every 4th session by both the patient and the therapist.
6. The Core Conflictual Relationship Theme (CCRT) is a rating scale instrument that indicates interactional patterns in treatment processes, which is used to study recurrent relationship patterns coming forth from the transcripts. Two independent raters, blind with respect to the research design, are trained to do the CCRT ratings. All treatment sessions are audiotaped and (partly) transcribed for the purpose of such qualitative analyses.
7. Biomarkers and epigenetics are analyzed by means of mass spectrometry of blood samples that are gathered at pre-treatment and post-treatment.
8. The Shortened Character-Temperament questionnaire (SCTI) is a personality questionnaire with 104 self-rated items, which assesses character and temperament profiles. It will be administered pre- and post-treament.
9. The Experiences in Close Relationships, Dutch version (ECR) is a self-report questionnaire with 36 items to assess adult attachment style. It will be administered pre-treatment and post-treatment.
10. The Zelfinventarisatievragenlijst Posttraumatische Stoornis (ZIL) is a symptom-specific questionnaire with 22 self-rated items, which assesses the presence of posttraumatic stress disorder symptoms. It will be administered pre-treatment, peri-treatment (at session 8) and post-treatment, and at 12-month follow-up.
11. The VAS for Countertransference is a visual analogue scale that inquires countertransference by the therapist. It consists of 7 subscales for countertransference and is completed by the therapist after treatment sessions 1-3, 5-7, 9-11, 13-15 and 17 -19.
12. The Therapist Response Questionnaire, Dutch version (TRQ) is a 79-item self-report questionnaire which measures countertransference in the therapist. It is completed by the therapist after sessions 4, 8, 12, 16 and 20.

Screening materials

1. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental (DSM) Disorders (SCID-I) is used to screen potential participants before the treatment process. If patients meet the criteria for major depressive disorder, additional screening is done, starting with the administration of the SCID-II to exclude patients with manifest substance abuse, acute psychotic symptoms and/or suicidal ideations, and to detect comorbidity. After treatment, the SCID-I and SCID-II are administered again to indicate changes in psychopathology.
2. The Clinical Diagnostic Interview (CDI), a semi-structured interview that assesses DSM-IV-TR Axis I and II symptoms narratively, is administered to indicate comorbidity and severity of symptoms from the patient’s experience.
3. Personality styles or potential participants are identified by the rating of transcribed CDIs, using clinical vignettes provided by Werbart and Forsström (2014). These vignettes includes a list of typical needs, concerns, relational attitudes, and coping mechanisms of both dependency and self-criticism, all rated on a 5 point rating scale ranging from ‘little or no match’ to ‘very good match (prototypical case)’. Inter-rater reliabilities observed with this procedure are adequately high (ranging between .85 and .95). A team of postgraduate research assistants is trained until adequate inter-rater reliability with an expert rater is reached. Inter-rater reliabilities observed with this procedure are adequately high (ranging between 0.85 and 0.95).
Prototype matching for each patient is conducted in supervised cartel discussions.
4. The personality styles identified by ratings, are validated by administration of the self-rating questionnaires the Personality Style Inventory (PSI) and the Depressive Experiences Questionnaire (DEQ). The PSI distinguishes between the dependent and the self-critical personality style. The DEQ distinguishes between the sociotropic and autonomous personality styles, which resemble the dependent and the self-critical personality style, respectively.
A number of materials such as the SCID, the CDI and the BDI-II-NL are based on the diagnostic typology described in DSM-IV-TR. As the DSM-IV-TR was recently replaced by DSM-V, but no (Dutch translations of) updated versions of the measures are available yet, in this study the current measures are still used. Nonetheless, we compared the DSM-IV and DSM-V thoroughly, to be able to anticipate changes in the SCID’s items over the course of our study.

Previous secondary outcome measures:
1. The Inventory of Interpersonal Problems-32 (IIP-32) is a self-rated questionnaire with 32 items that indicates the most salient interpersonal problems. It is administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
2. The Symptom Checklist-90-Revised (SCL-90-R) is a self-rated questionnaire with 90 items that indicates a range of psychopathology symptoms. It is administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
3. Outcome Questionnaire-45 (OQ-45) is a self-rated questionnaire with 45 items that indicates general wellbeing. It is administered pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up.
4. The shortened Depression Anxiety and Stress Scale (DASS) is a 21-item self-report questionnaire on the presence and severity of symptoms of depression, anxiety and stress. It is administered pre-treatment and post-treatment, at every session of the treatment process, and at 3-month, 6-month, 12-month and 24-month follow-up.
5. The Client Change Interview (CCI) is a semi-structured interview focused at patient experience of the process of change during and following the treatment process. It is administered around the 12th treatment session, at post treatment and at 6-month and 24-month follow-up.
6. An idiosyncratic complaint is formulated at the onset of treatment, and rated by the patient on a continuous scoring line (the far left end indicates absence of the complaint, the far right end indicates full presence and severe suffering from the complaint). It is rated retrospectively for the week before each treatment session.
7. The Working Alliance Inventory (WAI) is a 12-item questionnaire focused on the working alliance between the therapist and the patient as experienced during the treatment session. The questionnaire is completed every session by both the patient and the therapist.
8. Medication use changes are indicated at every treatment session.
9. Cortisol stress levels are analysed as indicators of stress, by means of mass spectrometry of saliva and hair samples. The saliva samples are gathered for four consecutive days (one sample early morning and one late evening every day) at pre-treatment and post-treatment, at sessions 4, 8, 12, and 16 during treatment, and at 3-month, 6-month, 12-month and 24-month follow-up. The hair-samples are gathered at pre-treatment, peri-treatment and post-treatment and at 6-month and 24-month follow-up.
10. Every treatment session is audiotaped. Sessions 4, 8, 12, and 16 of treatment are transcribed by independent transcribers who are blind to the research hypotheses. The Core Conflictual Relationship Theme (CCRT)—a rating scale instrument that indicates interactional patterns in treatment processes—is used to study recurrent relationship patterns coming forth from the transcripts. Two independent raters, blind with respect to the research design, are trained to do the CCRT ratings.
11. Cost-efficiency by means of health-care cost information is retrieved via the Inter-mutualistic Agency (http://www.nic-ima.be), covering a period starting 3 years pre-treatment until 2 years post-treatment. This is one of the only ways to gather objective information on a longer period before the patient enters therapy; and it can be used to get a clear picture of antidepressant medication use.

Measures of mediator variables
1. In case HA2 and/or HA3 are rejected, the PQS will be used to further investigate the therapeutic processes. The PQS is a researcher-rated 100-item Q-sort that offers a quantification of a broad range of process variables. A researcher will be trained until he or she reaches high inter-rater reliability with a qualified PQS-rater. After that, every fourth session will be rated to assess a variety of process variables and to study associations with outcome.
2. Therapists’ adherence to respective types of treatment will be assessed by means of a Treatment Fidelity Checklist, as proposed by Beck.

Screening materials
1. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental (DSM) Disorders (SCID-I) is used to screen potential participants before the treatment process. If patients meet the criteria for major depressive disorder, additional screening is done, starting with the administration of the SCID-II to exclude patients with manifest substance abuse, acute psychotic symptoms and/or suicidal ideations, and to detect comorbidity. After treatment, the SCID-I and SCID-II are administered again to indicate changes in psychopathology presence.
2. The Clinical Diagnostic Interview (CDI), a semi-structured interview that assesses DSM-IV-TR Axis I and II symptoms narratively, is administered to indicate comorbidity and severity of symptoms from the patient’s experience.
3. Personality styles or potential participants are identified by the rating of transcribed CDIs, using the list of criteria provided by Blatt and Ford. This list includes typical needs, concerns, relational attitudes, and coping mechanisms of both dependency and self-criticism, all rated on a 5-point Likert scale. Total scores for dependency and self-criticism range between 0 and 100. A team of postgraduate research assistants is trained until adequate inter-rater reliability with an expert rater is reached, will rate the patients on Inter-rater reliabilities observed with this procedure are adequately high (ranging between 0.85 and 0.95).
4. The personality styles identified by ratings, are validated by administration of the self-rating questionnaires the Personality Style Inventory (PSI) and the Depressive Experiences Questionnaire (DEQ). The PSI distinguishes between the dependent and the self-critical personality style. The DEQ distinguishes between the sociotropic and autonomous personality styles, which resemble the dependent and the self-critical personality style, respectively.

A number of materials such as the SCID, the CDI and the BDI-II-NL are based on the diagnostic typology described in DSM-IV-TR. As the DSM-IV-TR was recently replaced by DSM-V, but no (Dutch translations of) updated versions of the measures are available yet, in this study the current measures are still used. Nonetheless, we compared the DSM-IV and DSM-V thoroughly, to be able to anticipate changes in the SCID’s items over the course of our study.