The effectiveness of current treatment options for sociocognitive deficits and negative symptoms (NS) in schizophrenia spectrum disorders (SSD) remains limited. The cause of NS is thought to be an interference between the mesocorticolimbic dopamine system for social reward expectancy and the network for socioemotional processes. Oxytocin (OXT) may enhance functional connectivity between these neuronal networks. Lower plasma OXT levels correlate negatively with NS severity and deficits in social cognition in SSD. It has been shown that intranasal OXT administration improves social cognition in healthy subjects but in SSD results are inconsistent. According to the social salience hypothesis, the effect of OXT varies depending on the social context and individual factors. Also, OXT-mediated effects on psychopathology and NS may depend on genetic variants of OXT receptors (OXTR). In a pilot study, the investigators demonstrated a lower NS by OXT administration in the positive social context of MBGT in SSD. The investigators also demonstrated that NS and other symptoms improved after mindfulness-based group psychotherapy (MBGT). The aim of this study in individuals with SSD is to examine the effect of combining OXT administration with MBGT on NS, affect, and stress with psychological and biological markers. The main hypothesis to be tested is that the use of OXT compared to placebo prior to MBGT in patients with SSD will result in a greater reduction in NS. The research design is based on an experimental, triple-blind, randomized, placebo-controlled trial.
Schizophrenia spectrum disorders (SCZ) are severe mental illnesses with a lifetime prevalence of 1-2%. Three core syndromes characterize SCZ: positive and negative syndromes (NS), as well as a cognitive syndrome. The effectiveness of current treatment options for negative symptoms (NS) and sociocognitive deficits in schizophrenia spectrum disorders (SSD) remains limited. The cause of NS is thought to be an interference between the mesocorticolimbic dopamine system for social reward expectancy and the network for socioemotional processes. Oxytocin (OXT) may enhance functional connectivity between these neuronal networks. Lower plasma OXT levels correlate negatively with NS severity and deficits in social cognition in SSD. It has been shown that intranasal OXT administration improves social cognition in healthy subjects but in SSD results are inconsistent. According to the social salience hypothesis, the effect of OXT varies depending on the social context and individual factors. Also, OXT-mediated effects on psychopathology and NS may depend on genetic variants of OXT receptors (OXTR). In a pilot study, the investigators demonstrated lower NS by OXT administration in a positive social context of MBGT in SSD. The investigators also demonstrated that NS and other symptoms improved after mindfulness-based group psychotherapy (MBGT). The aim of this study in individuals with SSD is to examine the effect of combining OXT administration with MBGT on NS, affect, and stress. The main hypothesis to be tested is that the use of OXT compared to placebo prior to MBGT in patients with SSD will result in a greater reduction in NS, i.e. the difference in T7 - T0 of the negative syndrome subscale of the PANSS (Positive and Negative Syndrome Scale) after 4 weeks. The PANSS as a validated and structured clinical interview will be collected by a blinded psychiatrist. MBGT - sessions by experienced psychotherapists take place over four weeks. These sessions as a positive social context take place once a week in a group of about six patients. Participants received either synthetic oxytocin or a placebo 30 minutes before MBGT. The role of genetic variations (OXTR genes) for the treatment effect on NS will be explored too as well as the effect on various stress markers including cortisol levels and the endocannabinoid system, affect, group cohesion and mindfulness. The research design is based on an experimental, triple-blind, randomized, placebo-controlled trial.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
42
Charité Universitätsmedizin Berlin, Campus Benjamin Franklin
Berlin, State of Berlin, Germany
Change in PANSS Negative Symptoms
The Positive and Negative Syndrome Scale (PANSS) is one of the most widely used rater instruments for the assessment of the presence and severity of psychotic symptoms. Each scale comprises seven statements which are rated by the interviewer using a seven-point Likert format (from 1= absent to 7= extreme). The PANSS is reported to have satisfactory internal consistency, good interrater reliability and construct validity.
Time frame: Baseline (T0), post-intervention at week 4 (T4) and follow-up (week 8, T5)
Change and group differences in BNSS Brief Negative Symptom Scale
The Brief Negative Symptom Scale (BNSS) is a 13-item rater-based instrument designed for clinical trials and other studies that measures 5 domains: blunted affect, alogia, asociality, anhedonia, and avolition. The interrater, test-retest, and internal consistency of the instrument were strong, with respective intraclass correlation coefficients of 0.93 for the BNSS total score and values of 0.89-0.95 for individual subscales.
Time frame: Baseline (T0), post-intervention at week 4 (T7) and follow-up (week 8, T8)
Change and group differences in SNS Negative Symptoms
This is a 20-item self-reported questionnaire with five subscales, namely alogia, avolition, anhedonia, social withdrawal and diminished emotional range. These subscales cluster on two factors, the apathy and emotional components. Participants can estimate the answer to each question on a scale from 0 (strongly disagree) to 3 (strongly agree). The scale was shown to have good internal consistency with Cronbach's alpha = .87.
Time frame: Baseline (T0), post-intervention at week 2 (T3), post-intervention at week 4 (T9) and follow-up (week 8, T5)
Change and group differences in CDSS Calgary Depression Scale of Schizophrenia
The Calgary Depression Scale for Schizophrenia (CDSS) is a nine item clinician rated outcome measure that assesses the level of depression in people with schizophrenia. It is the only depression scale designed to assess depression in people with a schizophrenia spectrum disorder. It distinguishes depressive symptoms from negative symptoms and is sensitive to change.
Time frame: Baseline (T0), post-intervention at week 4 (T7) and follow-up (week 8, T8)
Change and group differences in cortisol saliva levels
Saliva samples will be taken before and after each MBGT session to determine Cortisol saliva levels
Time frame: Baseline (T0), pre- and post-intervention in week 1 - 4 (T1-T7) and follow-up (week 8, T5)
Change and group differences in DASS-21 Depression, Anxiety, and Stress Scale
The 21-item Depression, Anxiety, and Stress Scale (DASS-21) is assessed on a four-point Likert-scale ranging from (0) "did not apply to me at all over the last week" to (3) "applied to me very much last week." It shows internal consistencies of α \> 0.80 across the three subscales and has shown to be a useful measurement tool for patients with SSD.
Time frame: aseline (T0), post-intervention at week 2 (T3), post-intervention at week 4 (T7) and follow-up (week 8, T9)
Change and group differences in stress via visual analogue scale (Bubbles)
Stress via visual analogue scale. Self-rating instrument to measure stress through four items on a seven-point Likert-scale ranging from "not at all" (0) to "extreme" (6) visualized through bubbles increasing in size.
Time frame: Baseline (T0), pre- and post-intervention in week 1 - 4 (T1-T7) and follow-up (week 8, T8)
Change and group differences in PANAS (Positive and Negative Affect Scale)
The PANAS contains 20 items, each consisting of an adjective describing an emotion. The participants have to select how applicable this adjective is to their current state from 1 (not at all) to 5 (extremely). Ten items are assigned to the positive (e.g. "Excited") as well as the negative scale (e.g. "Fearful"). The reliability of the PANAS ranges from .86 to .93.
Time frame: Baseline (T0), pre- and post-intervention in week 1 - 4 (T1-T7) and follow-up (week 8, T8)
Change and group differences in PSP Social Functioning
The Personal and Social Performance Scale (PSP) is a rater-based questionnaire used to assess social functioning in patients with SSD. The PSP showed good test-retest reliability (ICC = 0.79) in patients with schizophrenia.
Time frame: Baseline (T0), post-intervention at week 4 (T7) and follow-up (week 8, T8)
Change and group differences in SMQ Mindfulness
The SMQ comprises 16 items that are rated on a seven-point Likert-scale ranging from (6) "agree totally" to (0) "disagree totally". Consequently, the total score ranges from 0 to 96, with a higher score indicating higher mindfulness. The internal consistency of the German version of the SMQ was Cronbach's α = 0.89.
Time frame: Baseline (T0), post-intervention at week 4 (T7) and follow-up (week 8, T8)
Change and group differences in GCQ-S Group Climate Questionnaire (Short Version)
The GCQ-S is a 12 item questionnaire designed to assess individual group members' perceptions of the group's therapeutic environment. It consists of three domains: Engaged, conflict and avoiding and will be used as a self-report, such as a rater-based instrument.
Time frame: Post-intervention at week 1-4 (T1-T7)
Change and group differences in endocannibinoid levels
Venous blood samples will be taken to determine the endocannibinoid levesls to obtain an individual baseline and comparison level.
Time frame: Baseline (T0), post-intervention week 1 (T1), post-intervention week 4 (T7) and follow-up (week 8, T8)
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