Cortisol in personalized treatment for posttraumatic stress disorder (PTSD)

Who can take part

• Patient group: Participants with PTSD (n = 160) will be recruited (1) at collaborating treatment centres, before the start of their trauma-focused therapy treatment, when they have at least a suspected PTSD diagnosis with an indication for trauma-focused therapy, or (2) independently from treatment centres, when they declare to have received a PTSD diagnosis by a doctor or specialist and currently experience considerable PTSD symptoms; these participants will be screened with a PTSD diagnostic interview (CAPS-5) to confirm current PTSD diagnosis (otherwise exclusion).Patients must be aged 18-64. If applicable, the expected waiting time until treatment is sufficient for participation, at least for part A of the study, with minimal overlap with treatment beng allowed (as specified in research protocol). Progression of patients into substudy B follows based on additional screening criteria, interest and feasibility. Control group: Healthy, non-trauma exposed control participants (n = 30) will be recruited from the general population in and around Nijmegen. Control participants only complete assessments from substudy A. Control participants must be aged 18-64 years. Inclusion criteria are no history of psychiatric disorders, and no history of childhood maltreatment. Hence, this group will reflect a healthy, non-trauma exposed control group, Control participants will be selected based on age, gender and education, with the aim to match the distributions of these relevant basic demographic variables to the (expected) distributions of the included patient group

Who cannot take part

• Patient group: • Current episode of psychotic or manic symptoms. • Daily intake of benzodiazepines, or otherwise irregular intake of benzodiazepines ("when needed") but unable to withhold intake from the day prior to each test session until the end of the each test session. An exception is made for low doses of short-acting benzodiazepines that are prescribed for insomnia (i.e. as sleep medication). • A relevant neurological disorder (e.g., stroke, epilepsy, Multiple Sclerosis) or severe physical disorder which is likely to impact assessment procedures or results. • Reports to be unable or unwilling to withhold recreational drug use and limit alcohol use from the day prior to each test session until the end of the each test session. • General learning disability, or known to have intelligence Quotient (IQ) < 80 • Body Mass Index (BMI) of >35. • If relevant, endocrine disorder and/or current or recent endocrine treatment (<1 month ago; for e.g., phechromocytoma, hyperthyroidism, Cushing's syndrome). • Current or recent regular use of corticosteroids (<1 month ago). • For women: Pregnancy. • Reports hypersensitivity to hydrocortisone or any of the tablet's auxiliary agents. • (Only for part B) Contraindications for MRI scanning (e.g., pacemaker, implanted metal parts, metal in or around the body, deep brain stimulation, severe claustrophobia). Note: based on the exclusion criteria above, it may be decided by the research team that a participant should onlyparticipate in part A of the study, but will be excluded from part B of the study Control group: • History of childhood maltreatment • Current or past psychiatric disorder • Use of psychotropic medication • Relevant neurological disorder (e.g., stroke, epilepsy, Multiple Sclerosis) or severe physical disorder which is likely to impact assessment procedures or results. • Reports to be unable or unwilling to withhold recreational drug use and limit alcohol use from the day prior to each test session until the end of the each test session. • General learning disability, or known to have intelligence Quotient (IQ) < 80 • Body Mass Index (BMI) of >35. • If relevant, endocrine disorder and/or current or recent endocrine treatment (<1 month ago; for e.g., phechromocytoma, hyperthyroidism, Cushing's syndrome). • Current or recent regular use of corticosteroids (<1 month ago). • For women: Pregnancy