The goal of this observational study is to investigate the brain physiological responses in depression and autism. The main questions aim to answer are:

1. Comparing the ratios of cortical excitation and inhibition among four groups: autism group, autism with depression group, depression group, and normal control group using Transcranial magnetic stimulation and electroencephalography (TMS-EEG). This study explores the relationship between the ratios of cortical excitation and inhibition and the severity of clinical symptoms.
2. Comparing the brain inflammation among four groups: autism group, autism with depression group, depression group, and normal control group using Positron emission tomography (PET). This study investigates the relationship between brain inflammation and the severity of clinical symptoms.
3. The mutual influence between the severity of brain inflammation and Excitatory/inhibitory imbalance (E/I imbalance).

Participants will receive clinical assessment, neurocognitive function tests, TMS-EEG, gamma oscillation, and PET examinations.

Inclusion Criteria:

• Autism group : Adults aged 20-50 diagnosed with autism spectrum disorder。Intelligence Quotient(IQ) > 70, with autonomous abilities.
• Autism group with comorbid depression : Adults aged 20-50 diagnosed with autism spectrum disorder. Diagnosed with depression. IQ > 70. Not on antidepressants for at least one week, with autonomous abilities.
• Major depression disorder group : Adults aged 20-50. Diagnosed with major depressive disorder according to Diagnostic and Statistical Manual of Mental Disorders-IV-TR(DSM-IV-TR). IQ > 70. Not on antidepressants for at least one week, with autonomous abilities.
• Typically developing control group : Adults aged 20-50. Never diagnosed with autism spectrum disorder. Never diagnosed with depression. IQ > 70, with autonomous abilities.

Exclusion Criteria:

• Previously diagnosed with bipolar disorder, schizophrenia, attention deficit hyperactivity disorder (ADHD), or substance use disorder according to DSM-IV.
• Previously suffered from major medical or neurological diseases.
• Brain structural abnormalities (e.g., brain tumor or arteriovenous malformations) or neurological diseases (e.g., meningitis, encephalitis, stroke, or epilepsy).
• Previously undergone or soon to undergo brain surgery, or have metal implants in the head or neck area, such as neuro-stimulators or cochlear implants.
• Have a cardiac pacemaker.
• Pregnant participants.
• Participants with strong suicidal intentions.
• Other conditions that render the patient unable to cooperate, such as unsuitability after screening, unstable physical illness, or refusal to sign the informed consent.
• Claustrophobia, unable to undergo positron emission tomography(PET) and functional magnetic resonance imaging (fMRI) scans.
• Taking medications that may affect Excitatory/inhibitory balance (E/I balance).

National Taiwan University Hospital