Rationale: Synthetic glucocorticoids can result in neuropsychiatric adverse effects in a minority of patients. Although, not all patients experience severe adverse effects, more subtle emotional disturbances are often experienced. With a variation on ecological momentary assessment (EMA), with a daily assessment, the investigators will collect the patient's emotional symptoms in real time and in the patients natural environment during corticosteroid treatment. With dynamic time warping (DTW) analysis the investigators aim to analyse the temporal dynamics of different emotional states and visualize these emotional dynamics over time. The patient dermatologist and neurologist will receive the idiographic results as a feedback form, which may give insights into temporal (and possibly causal) central emotions, which may help to overcome mood disturbances.

Objective: Mapping emotional dynamics with DTW analysis in 6 mycosis fungoides or Sezary syndrome patients and 6 chronic cluster headache patients treated with systemic corticosteroids.

Study design: Case series report study. Study population: Six patients with cutaneous T-cell lymphoma (type mycosis fungoides and/or Sezary syndrome), and six patients with cluster headache.

Main study parameters/endpoints: An idiographic DTW analysis of emotional dynamics during and after corticosteroid treatment in six mycosis fungoides and/or Sezary syndrome patients, and six chronic cluster headache patients.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: There are no additional risks associated with study participation. The patients who will participate in this case series study need to complete a 5-minute survey daily using a m-Path smartphone app during corticosteroid treatment. The data analysis may increase the insight into centrality measures of emotions and the emotional clusters for the individual patient.

This is a case series study in which we want to map emotional dynamics with DTW analysis in 6 mycosis fungoides and/or Sezary syndrome patients and 6 chronic cluster headache patients, who will be treated with a corticosteroid regime. Duration of the study will approximately be 40-60 days, depending on the duration of the treatment:

• The mycosis fungoides and/or Sezary syndrome patients are treated for approximately 40 days.
• The chronic cluster headache patients are treated for approximately 60 days.

The patient will be treated according to standard regular care. This will not change. For study purposes, a 15 minute explanation of the survey will be given. We will ask the patient to install the m-Path app on their smartphone, and to complete the daily survey (with 23 statements with a slider) on his/her phone during the treatment period, which will take approximately 5 minutes per day. At the end of the study the patient will get the results visualized, with a 30 minute explanation of the results, which may increase insights of the patient's emotions dynamics over time during corticosteroid treatment.

Inclusion Criteria:

• Mycosis fungoides and/or Sezary syndrome patients
• Chronic cluster headache patients
• Corticosteroid treatment

Exclusion Criteria:

• N/A

Mycosis fungoides and/or Sezary syndrome patients and cluster headache patients who will be treated according to standard regular care, which is a corticosteroid treatment regime.