Some of the more common disorders are depression, bipolar disorder, dementia, schizophrenia and anxiety disorders. Symptoms may include changes in mood, personality, personal habits and/or social withdrawal. Mental health problems may be related to excessive stress due to a particular situation or series of events..Early identification, accurate diagnosis and effective treatment of mental health and substance use conditions can alleviate enormous suffering for young .Major mental illnesses such as schizophrenia or bipolar disorder rarely appear "out of the blue." Most often family, friends, teachers or individuals themselves .Each illness has its own symptoms, but common signs of mental illness ins and adolescents can include the following: Excessive worrying or fear. Feeling excessively sad or low. Confused thinking or problems concentrating and learning. Extreme mood changes, including uncontrollable "highs" or feelings of euphoria..