Honest, Open, Proud for Soldiers with Mental Illness

Inclusion Criteria: * At least one self-reported current axis I or axis II disorder according to DSM-5, which is not restricted to only substance-related disorder(s) * Age 18 or above * Ability to provide written informed consent * Fluent in German (needed for self-report measures) * At least a moderate level of self-reported disclosure-related distress/difficulty (score 4 or higher on the screening item 'In general, how distressed or worried are you in terms of secrecy or disclosure of your mental illness to others?', rated from 1, not at all, to 7, very much) * Current inpatient, day-clinic or outpatient treatment at the Center for Military Mental Health, Berlin, Germany * from April 2018 onwards we decided to also include non-military first responders (fire fighters or police officers) who are treated in the Center for Military Mental Health, Berlin, Germany Exclusion Criteria: * Self-reported diagnosis of only a substance- or alcohol-related disorder, without non-substance related current psychiatric comorbidity. We will exclude people who only have a substance-/alcohol-related disorder because the disclosure of these disorders is not the topic of the HOP intervention * Intellectual disability * Organic disorders