Arnold Chiari Malformation (ACM) is a disorder of embryologic development that is characterized of herniation of the cerebellar structures through the foramen magnum by four types. ACM type 1 (ACM 1) consists in cerebellar tonsil herniation, which is sometimes associated with other abnormalities, including syringohydromyelia, hydrocephalus and skull base alterations. To date, five cases of psychiatric disorders comorbid with ACM-I have been reported. We here present an apathetic patient have delayed diagnosis ACM-I and severe hydrocephalus and comorbid major depressive disorder.

A 36-year-old, male patient who is married and two children, was admitted to hospital with don’t want to make anything, despondency, thoughts of have an incompetency, uselessness and want to death, tiredness, weakness complaints which are increased day by day last 2 months. He was diagnosed with major depression after the psychiatric evaluation and hospitalised. He has unwillingness, tiredness and headache complaints which are started when he was 20 years old and he used antidepressant, anxiolytic, and low dose anthipsycotic drugs under psychiatrist control at this years. In radiologic evaluation, Arnold Chiari type 1 and severe hydrocephalus was detected in brain magnetic resonance imaging.

ACM 1 is related to hydrocephalus as a result of posterior fossa hypoplasia and causes spinal injury by obstruction to cerebrospinal fluid (CSF) flow at the foramen magnum. Apathy is a common yet often overlooked symptom in hydrocephalus. This symptom may be a significant obstacle for cognition and quality of life and is associated with increased level of depression.

The authors have not supplied their declaration of competing interest.