A. Genetic factors: About 1/4 to 1/5 of schizophrenia patients have patients with mental illness in their families. B. Pathological changes in neurobiochemical substances (neurotransmitters) in the brain: Laboratory studies over the past 30 years have confirmed that changes in the neurobiochemistry of the brain have a significant impact on human mental activity. The main ones associated with the development of the disease are hyperfunction of dopamine (DA) or increased sensitivity of dopamine receptors. C. Somatobiological factors: Endocrine factors are important, and most patients develop the disease around the time of puberty, hence the name “youthful” schizophrenia. Some female patients have an acute onset after childbirth, and there are more patients who relapse during menopause. D. Pre-morbid personality traits: About 70% of patients with this disorder have a withdrawn, timid, introverted, sensitive, fanciful, and illogical thinking. E. Psychosocial factors: The common clinical psychosocial factors include family disputes, neighborhood discord, death of relatives, frustration at work or in love, etc., i.e., pre-morbid mental stimulation. In summary, genetic factors have an important role in the development of the disease, most patients have introverted personality traits, while psychosocial factors and certain physical biological factors may influence the occurrence of the disease as risk factors. The symptoms of the disease are complex and varied. Early symptoms are related to the form of onset (acute, subacute, or chronic) and clinical type. Slow onset is the most common clinical condition. Early symptoms are mostly personality changes and neurosis-like symptoms: abnormal personality, laziness, lack of discipline, unprovoked temper tantrums, sensitivity, paranoia, self-talk, self-laughter, or unexplained fear. Some patients show headaches, insomnia, emotional instability, and decreased ability to study and work. Some patients are also afraid of getting dirty, saying the wrong thing, or having symptoms of schizophrenia that can be divided into two main categories: characteristic symptoms and other common symptoms. The former reflects the characteristics of “schizophrenia”, while the latter can also be seen in other functional or organic psychiatric disorders. Other common symptoms include verbal hallucinations, perceptual syndromes (seeing someone’s face grow longer, having large eyes or seeing one’s own face become ugly, or feeling one’s head leave one’s body), and delusions. Schizophrenia causing endocrine dysregulation has been of interest to the medical community, and this paper reviews the correlation between schizophrenia and thyroxine. This includes the correlation between thyroxine and the psychotic symptoms of schizophrenia, and the correlation between thyroxine and medications.