Personality disorders (PDs) are characterized by an enduring, pervasive and pathological pattern of thoughts, feeling and behavior expressed in a dysfunctional and inappropriate manner, which is deviant from societal norms. In the DSM-IV, personality disorders are grouped into 3 clusters: the 'odd, eccentric' cluster A (paranoid, schizotypal and schizoid PD), the 'dramatic' cluster B (borderline, antisocial, histrionic and narcissistic PD), and the 'anxious' cluster C (avoidant, dependent and obsessive-compulsive PD) [1
]. Despite the frequent application of prolonged psychotherapy for people with personality disorders, controlled research into the clinical and cost-effectiveness of psychotherapy is scarce [2
]. This is remarkable, given the substantial burden on patients and society. Moreover, PDs are highly prevalent, as seen in numbers ranging from 3 to 15% in community population up to as high as 80-90% in secondary health care settings [3
]. PD-patients show chronic dysfunctions on social and interpersonal level [7
] and experience substantial impairment in work and basic self-care [11
], leading to an enormous negative impact on the patient's life and the life of his/her close relatives. Furthermore, PDs and personality-related factors play a key role in the development and progress of other mental disorders, as demonstrated in numerous cross-sectional and prospective studies [12
Apart from patients, also society bears the costs of chronic personality pathology. Factors attributing to these notable costs are increased health care utilization, productivity losses, and unstable employment throughout the lifespan [17
]. A recent study showed that the costs of untreated PDs in the Netherlands are substantially higher than those of other psychopathology like depression or generalized anxiety disorder [19
The evidence on treatment effectiveness for PDs that exists so far is mostly restricted to borderline PD (BPD) [20
]. Several reviews report large effect sizes of specialized psychological treatments for all PDs in general [21
] and specifically for cluster-C [22
]. However, it should be noted that most studies into treatment of non-BPD PDs are of questionable methodological quality and show conflicting results. A few RCTs focused on cluster-C PDs. Emmelkamp et al. [23
] showed greater improvement in cognitive over psychodynamic psychotherapy for Avoidant PD, while Svartberg, Stiles & Seltzer [24
] found these treatment forms to be equally effective for Cluster C PDs. Another study [25
] comparing manualized versus non-manualized dynamic psychotherapy showed equal decreases in the severity of PD symptoms, but both treatment conditions failed to reduce psychiatric symptoms to a 'healthy' level at post-test. Inconsistent findings also appear when focusing on different treatment modalities instead of different theoretical frameworks for cluster C. Recent evidence suggests that outpatient psychotherapy is equally effective as day treatment [26
], while a naturalistic study [27
] showed only modest improvement for outpatient therapy following day treatment in which considerable progress was made. Bartak et al. [28
] compared different treatment modalities for cluster C in a multicenter non-experimental study in the Netherlands, and results favored short-term inpatient treatment over other treatment modalities. On top of these contradictory findings, studies on treatment effectiveness involving cluster C are often difficult to interpret because this group of PDs is mostly not the main research focus but partly allowed as comorbid psychopathology (e.g. [29
]). Methodologically sound scientific investigation of treatment effectiveness for paranoid, histrionic and narcissistic PD hardly exists [31
In a budget-constrained society, other important aspects in the evaluation of a new treatment form are costs and benefits of treatment. Unfortunately, for this patient group the same paucity of controlled cost-effectiveness studies is seen as with clinical effectiveness. The few studies that suggest cost-effectiveness often are not based on formal and well-prepared cost analyses [34
]. An exception herein is an economic evaluation study alongside the Dutch non-experimental study mentioned before, in which cost-effectiveness of different treatment modalities for both cluster B and C PDs is assessed [35
]. Results show that optimal treatment choice depends on what threshold is considered acceptable. Although this research group executed pioneering research in economic evaluations for non-BPD patient groups, findings are difficult to interpret because of different focus (modalities instead of theoretical framework) and non-randomization of patients.
Schema therapy (ST) gained a lot of attention the past decade as a promising treatment for PDs. Clinical effectiveness is shown for borderline PD both in an extensive RCT (comparing ST head-to-head with Transference Focused Psychotherapy (TFP) [37
]) and in a Dutch implementation study [38
]. Also in group format ST showed positive results for borderline PD [39
]. The first RCT mentioned demonstrated ST to be less costly and more effective than TFP, so preferable in terms of cost-effectiveness [40
Because the aforementioned shortcomings, the need for properly designed studies of psychological interventions for non-Borderline PDs is pressing [33
]. This is especially important as psychological treatment is considered to be the treatment of choice for these disorders [34
]. Despite some evidence for the effectiveness of ST techniques for PDs other than borderline [42
], properly designed effectiveness and economic evaluation studies comparing ST with other psychological treatments for non-borderline PDs are lacking. The main objective of this study is to evaluate the clinical and cost effectiveness of ST for a group of 6 PDs: avoidant, dependent, obsessive-compulsive, paranoid, histrionic and narcissistic PDs. Other PDs (borderline, antisocial, schizotypal and schizoid) are excluded as they are deemed to require highly specialized treatment protocols and higher dosage of treatment. In this study a treatment protocol of 50 ST-sessions is compared to treatment as usual (TAU). To assess to what degree a possible positive effect of ST is the result of the effects of a new specialized and promising treatment, we add the comparison of TAU with another specialized treatment, clarification oriented psychotherapy (COP), a form of client centered therapy developed for PDs [43
], to the design. Apart from the clinical effect study and economic analysis, in a qualitative research part patients and therapists are asked to provide insight in helpful and not helpful aspects of the ST protocol. By collecting input from direct users, valuable information is obtained to improve the ST protocol and tailor it to the needs of primary stakeholders.
The following research questions are defined:
How do ST and COP compare to TAU, in terms of recovery from PD-diagnosis, reduction of psychopathological symptoms and improvement of quality of life?
Are these new treatments better in retaining patients in therapy than TAU?
From a societal perspective, are ST and COP preferable to TAU in terms of costs, effects and utilities?
Patient and therapist perspectives
What do patients and therapists believe to be helpful and not helpful factors in the ST protocol?
Based on the superiority of ST found in previous research, we hypothesize that (a) ST shows greater clinical improvement than TAU, and (b) seen from a societal perspective, ST is more cost effective in terms of costs and utilities. Similarly, we test whether another specialized treatment of PD, COP, is superior to TAU in these respects.