The participant collective will include 3 groups of 200 persons, consisting of patients
with schizophrenia, their healthy relatives and healthy controls that are not related to
the patients. The patients must be diagnosed of schizophrenia according to DSM-5 to be
included in the study and will be excluded when there is a further psychiatric
comorbidity that dominates in the clinical appearance. All participants have to be aged
from 18 to 80 years, be mentally and contractually capable to give their consent to study
participation and may not be pregnant or have a structural neurological disease. The
healthy participants must not suffer from a psychiatric disorder themselves and,
additionally, the control subjects must not have psychiatric disorders in the family
history of their first-degree relatives.
Every participant will undergo the same examinations, tests and measurements. All
subjects will be taken a blood sample of 30 milliliters of blood that will be tested for
antibodies against the NMDA receptor, neuronal growth factors, components of the
glutamatergic and GABAergic metabolism and markers for the integrity of the blood brain
barrier. In addition to that, a genetic analysis to identify risk alleles for
schizophrenia and important glutamatergic and GABAergic genes will be performed. A
medical history of every subject will be taken, including medication, somatic and
psychiatric disorders. Furthermore, a row of psychiatric ratings scales as well as
neuropsychological and neurological tests will be performed.
These will include
Structured Clinical Interview for DSM Disorders (SCID)
Mini-RDoC
Short Form Health 36 (SF-36)
Personal and Social Performance Scale (PSP)
Positive and Negative Syndrome Scale
Berner Psychopathologie-Skala
Calgary Depression Rating Scale for Schizophrenia
Conners' Adult ADHD Rating Scales (CAARS)
Wender Utah Rating Scale (WURS-k)
Clinical Global Impression (CGI)
Global Assessment of Functioning (GAF)
Extrapyramidal Symptom Rating Scale (EPS)
Heidelberg Neurological Soft Signs Scale
Brief Assessment of Cognition in Schizophrenia
d2 test
Every study participant must undergo an EEG measurement while different, neutral visual
(fixation cross or movies without sound) and auditive stimuli (tones or clic trains) will
be presented to them. They will be instructed to ignore the auditive stimuli. Resting
state, auditory steady state response (ASSR) and two different auditory mismatch
paradigms will be used. Without contradiction for the conduction of an MRI measurement, a
combined EEG/ MRI measurement and a pure MRI measurement (without EEG) using the same
paradigms are intended. It will also include structural (T1, T2 and diffusion tensor
imaging) MRI and MR spectroscopy of glutamate and GABA. All the previously mentioned
examinations are planned to take place on the same day with an approximate expenditure of
time of five hours. If necessary, the examinations may also take place on different days,
providing that there will be a maximum of three weeks between the first and the last
measurement. Except from the blood withdrawal, we intend repeating all the measurements
for a second time. This repetition must take place at least one day and not later than
three years after the first measurement. It will not be necessary to repeat the clinical
and neuropsychological tests if the first testing does not date back more than 6 weeks.
In a second part of the study, we want to generate induced pluripotent stem cells (iPS
cells) from 15 participants of every study group. For this purpose, a further blood
sample of 20 milliliters of blood must be taken. The participants of the second part of
the study will be selected based on special genetic, EEG or fMRI characteristics revealed
in the first part of the study if they agree to be contacted again.