Introduction: Amyotrophic lateral sclerosis is a progressive neurodegenerative disease with undetermined etiology. Due to diverse symptomatology, it requires a thorough differential diagnosis, with consideration of conversion disorders. The presented thesis describes a case of a young man hospitalized in the Department of Psychiatry in order to verify the possible psychogenic basis of his symptoms, which previously were considered to be a manifestation of neurological disease with an unfavorable prognosis. Aim: The aim of the thesis is to raise the issue of a multidisciplinary approach to diagnostic process in medicine, as well as taking into account the legitimacy of including psychiatrists, psychologists, and psychotherapists in diagnostic teams. Case study: We present a case report of a man who has been experiencing progressive feeling and walking problems for the past several years, which originally suggested a neurological or rheumatological disease. Earlier observations and medical tests had led to a diagnosis of amyotrophic lateral sclerosis. After several years, the diagnosis was excluded, and the patient was referred to the Department of Psychiatry to determine the possible psychogenic basis of his symptoms. Diagnostic methods used during the patient’s hospitalization confirmed the conversational nature of his symptoms, and both pharmacological and psychotherapeutic treatment caused reduction of severity of his symptoms and allowed him for a gradual return to independent functioning. Conclusion: Analysis of the collected data, including patient’s life history and a course of his treatment, indicates the validity of a holistic approach to medical problems, which implies the inclusion of specialists in the field of psychiatry, psychology, as well as psychotherapists in diagnostic teams. Such a multidimensional view of the patient and the source of his symptoms may allow for faster diagnosis and may also contribute to reducing the risk of making mistakes such as an incorrect assessment of factors triggering the disease process.