The Efficacy of Treatments to Improve Self-esteem

The goal of this study is to examine the effectivity of two self-esteem interventions (COMET (Korrelboom) and CBT (De Neef)) in a general psychiatric population.

The main questions it aims to answer are:

* is there a difference between the two interventions in effectiveness on increasing self-esteem?
* is there a difference between the two interventions in effect on levels of anxiety, depression and general mental health?
* are found effects on levels of anxiety, depression and general mental health associated with changes in self-esteem?
* is the ability to use imagination a moderator for outcomes in both conditions?

Participants are randomised over both conditions. At baseline (T0), end of treatment (T1) and follow-up at 6 months (T2) several outcome measures are conducted, such as RSES, DASS and MHC-SF.

In this study, the investigators will examine the effectivity of self-esteem interventions.

To achieve this goal, the primary aim of this study is to examine if there is a difference in effectiveness between two interventions that have shown to be effective in ameliorating levels of low self-esteem in previous studies (ie. COMET (Korrelboom) and CBT (De Neef)).

Secondly, the investigators would like to find out if self-esteem interventions have an effect on levels of depression, anxiety and general mental health. This would give us a better understanding of the role of self-esteem as a trans-diagnostic factor.

The final aim of this study is to find out if some patients might profit more from one intervention over the other. One of the main differences between both interventions is that COMET heavily relies on imagination techniques and CBT does not. It could be possible that the extend to which patients are able to profit from an intervention which relies on imagination, depends on the ability or vividness in which they are able to use imagery. In this study the investigators will investigate if the ability to use mental imagery has an effect on treatment effects.

Design - In this study, research questions will be answered using a randomized clinical trial. After inclusion, patients are randomly assigned to one of the two conditions: 9 weeks of COMET + (ongoing) TAU versus 9 weeks of CBT + (ongoing) TAU. After baseline assessment participants will be randomized.

Population - All participants are adult (aged 18-65) outpatients of the regional community mental health teams of GGZ Noord-Holland Noord, a large secondary mental health care centre in the Netherlands with several locations. These teams treat patients with serious and complex psychiatric problems with any DSM-5 diagnosis (except those with a primary diagnosis of drug or alcohol related disorders and those with severe learning disabilities).

Including criterium is a self-perceived low self-esteem established by both patient and caregiver by means of (consent to) referral for self-esteem treatment.

Eligibility Criteria:
Inclusion Criteria:

- A self-perceived low self-esteem established by both patient and caregiver by means of (consent to) referral for self-esteem treatment.

Exclusion Criteria:

* severe suicidality for which hospitalization or other forms of crisis care is necessary,
* acute psychosis,
* current manic episode,
* current alcohol or drug abuse,
* insufficient knowledge of the Dutch language,
* illiteracy
* being unable to identify at least one positive aspect of oneself, which does not need to be felt as convincing for the participant. The latter is an excluding criterium formulated by the COMET protocol.