Individual psychotherapy for cluster-C personality disorders: protocol of a pragmatic RCT comparing short-term psychodynamic supportive psychotherapy, affect phobia therapy and schema therapy (I-FORCE)

BACKGROUND

Cluster-C personality disorders (PDs) are highly prevalent in clinical practice and are associated with unfavourable outcome and chronicity of all common mental health disorders (e.g. depression and anxiety disorders). Although several forms of individual psychotherapy are commonly offered in clinical practice for this population, evidence for differential effectiveness of different forms of psychotherapy is lacking. Also, very little is known about the underlying working mechanisms of these psychotherapies. Finding evidence on the differential (cost)-effectiveness for this group of patients and the working mechanisms of change is important to improve the quality of care for this vulnerable group of patients.

OBJECTIVE

In this study, we will compare the differential (cost)-effectiveness of three individual psychotherapies: short-term psychodynamic supportive psychotherapy (SPSP), affect phobia therapy (APT) and schema therapy (ST). Although these psychotherapies are commonly used in clinical practice, evidence for the Cluster-C PDs is limited. Additionally, we will investigate predictive factors, non-specific and therapy-specific mediators.

METHODS

This is a mono-centre randomized clinical trial with three parallel groups: (1) SPSP, (2) APT, (3) ST. Randomization on patient level will be pre-stratified according to type of PD. The total study population to be included consists of 264 patients with Cluster-C PDs or other specified PD with mainly Cluster-C traits, aged 18-65 years, seeking treatment at NPI, a Dutch mental health care institute specialized in PDs. SPSP, APT and ST (50 sessions per treatment) are offered twice a week in sessions of 50 min for the first 4 to 5 months. After that, session frequency decreases to once a week. All treatments have a maximum duration of 1 year. Change in the severity of the PD (ADP-IV) will be the primary outcome measure. Secondary outcome measures are personality functioning, psychiatric symptoms and quality of life. Several potential mediators, predictors and moderators of outcome are also assessed. The effectiveness study is complemented with a cost-effectiveness/utility study, using both clinical effects and quality-adjusted life-years, and primarily based on a societal approach. Assessments will take place at baseline, start of treatment and at 1, 3, 6, 9, 12, 18, 24 and 36 months.

DISCUSSION

This is the first study comparing psychodynamic treatment to schema therapy for Cluster-C PDs. The naturalistic design enhances the clinical validity of the outcome. A limitation is the lack of a control group for ethical reasons.

TRIAL REGISTRATION

NL72823.029.20 [Registry ID: CCMO]. Registered on 31 August 2020. First participant included on 23 October 2020.

Unconscious classical conditioning of sexual arousal: evidence for the conditioning of female genital arousal to subliminally presented sexual stimuli

INTRODUCTION

Although the assumption that sexual behavior is at least partly learned is common across theories of sexual behavior, classical conditioning of sexual response in women has been seldom studied.

AIM

The study of unconscious classical conditioning of appetitive sexual responses in women.

MAIN OUTCOME MEASURES

Vaginal pulse amplitude assessed by vaginal photoplethysmography, and ratings of sexual affective value.

METHODS

Pavlovian conditioning was examined in 18 sexually functional women by using two erotic pictures as conditional stimuli (CSs) and genital vibrotactile stimulation as unconditional stimulus (US). During the acquisition phase, the CSs were presented briefly (30 ms) and were masked by an immediately following masking stimulus. Only one CS (the CS+) was followed by the US during the acquisition phase. Conditioned responses were assessed during the extinction phase with supraliminal presentations of the CS+ and the CS-.

RESULTS

Vaginal pulse amplitude was higher in response to the CS+ than during the CS- during the first extinction trial. There was no conditioning effect on ratings of affective value.

CONCLUSION

The experiment demonstrates evidence for unconscious conditioning of genital responses in women, but no evidence for evaluative conditioning. The results add to the limited evidence for classical conditioning of sexual arousal in women, and to increasing evidence for associative emotional learning without awareness.