V: Mental and behavioural disorders

F99-F99: Unspecified mental disorder

Unspecified mental disorder refers to a mental or behavioral health condition whose specific symptoms or presentation do not neatly fit into a single defined category. This term is often used when an individual presents clear signs of psychological distress, but these do not correspond sufficiently to one particular mental disorder as outlined in diagnostic manuals. The causes of mental disorders are diverse, and can include genetic factors, traumatic experiences, and imbalances in brain chemistry. Symptoms vary greatly and are dependent on the specific characteristics of the individual's distress, but can include mood disturbances, changes in thinking or perception, altered behavior, and problems with social interactions. The progression of these disorders can also vary, with some individuals experiencing long periods of symptom reduction, while others may have more chronic conditions. These disorders, although primarily affecting the brain, can have wide-ranging impacts on various systems in the body, including the cardiovascular and immune systems.