1. Notice Whether the Person is Acting Strangely
One of the most common signs of mental illness is a person suddenly changing her lifestyle. For instance, if the person used to exercise daily but suddenly sits in front of the television all day, she may have developed a mental disorder. Also, if a very shy person suddenly becomes friendly to the point of being loud, a change in mental health may be at fault. Likewise, giving up favorite hobbies may indicate a problem. These are usually the signs of a mental illness, such as depression or bipolar disorder. People with bipolar disorder may change how they act more frequently than other people with mental disorders.
2. Is the Person Behaving or Speaking Inappropriately?
Many people with mental disorders are stuck in a different reality than people with healthy minds, and their behavior shows it. People who dress inappropriately, such as wearing snowsuits to the beach, may be exhibiting signs of a mental illness. People with mental disorders may also say inappropriate things or speak too loudly or too softly. Schizophrenics tend to be too loud, and their train of thought, while easy to hear, will not make any sense to those listening.
Be careful when judging behavior, however. An act that is inappropriate is not necessarily a symptom of a mental disorder. Someone acting or talking inappropriately may simply have a weird sense of humor, be a social rebel or have a tendency towards rudeness. Consider all the factors that may be involved before deciding whether the behavior is the sign of a mental disorder.
3. Does the Person Have Trouble Thinking?
Someone suffering from a mental disorder will not be thinking clearly. If someone seems constantly confused or has trouble concentrating, she may be displaying symptoms of a mental illness. Notice also is she is having difficulty remembering things above and beyond the usual absentmindedness.
4. How Is the Person Coping With Day-to-Day Activities?
Another factor is how well a person copes with taking care of himself and his home. Neglecting basic activities, such as washing up or doing laundry, can be a symptom of a mental disorder. A person may also neglect his bills, ignore home repairs that must be made or even starve himself due to his illness.


