In depression, this could mean trouble focusing and remembering things. You may feel muddled trying to coordinate routine tasks, or you may feel more indecisive than usual.
Similar problems with memory and concentration can occur with schizophrenia, along with difficulty solving problems and slower reaction times.
Other mental illnesses have similar and distinct cognitive problems and, not surprisingly, these issues can affect day-to-day functioning. This could be pronounced, such as problems at school or work, or more subtle, like difficulty navigating bills and appointments.
Cognitive problems can lead to some of the changes that may signal a mental illness: absenteeism from school, dropping grades, missing work. “All of these dramatic changes are warning signs,” Dr. Nemeroff says.
Trouble sleeping
Up to 80% of people with a mental illness have problems with sleep. It’s especially notable in different anxiety disorders, depression, attention deficit hyperactivity disorder (ADHD), and bipolar disorder.
It could mean sleeping too much or too little, tossing and turning, or waking up a lot during the night–and the disturbances can affect treatment.
There’s also a chicken-or-egg aspect: Sleep disorders sometimes up your risk of developing a mental illness.
Everyone can benefit from a good night’s sleep. For most people, that means seven to nine hours a night. Even if you have a mental health condition, the same tricks that work for others might work for you: cutting down on caffeine, exercising (though not right before bed), going to bed and waking up at the same time every day, and not taking your phone or laptop to bed with you. Therapy and medications can also help.
Appetite changes
Not wanting to eat or refusing to eat entirely are the central symptoms of anorexia nervosa, a serious psychiatric disorder. Anorexia often occurs alongside other mental illnesses, including depression and anxiety disorders. Binge-eating disorder and night eating have been linked to schizophrenia.
Eating less or a loss of appetite or interest in food can also be a sign of depression, anxiety, or even everyday stress. Of course, not eating enough can lead to weight loss, and, when dramatic, can be a visible indicator that something is wrong.
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Unusual behavior
One of the main warning signs of a mental illness is change, Dr. Everett says. Maybe a chatty person clams up, or an introverted person becomes oddly outgoing.
“Often these kinds of illnesses don’t happen one day to the next,” she explains. “They happen over time, but the time can be something as short as a couple of weeks or a month. We compare the way things are now to the person’s history.”
While half of all mental illnesses appear by the age of 14, according to the American Psychiatric Association, it may be easier to identify such changes in adults, she adds. Three-quarters of mental illnesses appear by the time a person is 24.
If you notice several of these warning signs in yourself or a loved one, consider bringing up the symptoms with a mental health professional.
