Nearly 1 in 5 U.S. adults live with a mental illness, according to the National Institute of Mental Health. Over the past decade, mental illness has become more discussed and less stigmatized, but many individuals struggling with mental health are still hesitant to talk about it. Others are undiagnosed and may not even realize their mental health is in decline—attributing their symptoms to other causes or ignoring them completely.

According to the NIH, mental illness is more likely to affect women and young adults between the ages of 18 and 25. A high number of adolescents in the United States also struggle with mental illness. More than 40 percent of 13- to 16-year-olds have a mental disorder and about 22 percent have severe impairment, according to the NIH.

Some symptoms of mental illness are easy to identify and diagnose, while others can be a bit tricky to notice—even for the individual experiencing them. This is especially true for more mild cases of mental illness. Because the mind and body are so intertwined, there are many physical indications of unstable mental health that may not be immediately attributable or identifiable.

Here are 15 common, yet surprising signs of mental health issues:

  1. Insomnia and sleep changes. Sleep is one of the biggest indicators of mental state. Insomnia, light sleeping, vivid dreams, night terrors and other sleep issues can point to a high level of stress or to mental health issues such as anxiety or depression. If an individual’s heart rate is high because of stress or anxiety, or if they are experiencing a hormone imbalance related to mental illness, this can affect the body’s circadian rhythm and interfere with the natural sleep process.
  2. Appetite changes. Both increased appetite and reduced appetite can be symptoms of an underlying mental health issue, as can weight gain and weight loss. Depending on the individual, these changes in appetite and food consumption may lead to fatigue, changing energy levels, and fluctuating mood, which can in turn exacerbate mental illness.
  3. Loss of interest or pleasure. One way mental illness can manifest is in a loss of desire or interest in activities once found pleasurable, including sex. This can be a sign that the body’s hormones and chemicals are not functioning properly or may be suppressed in some way that makes it difficult to feel pleasure or desire.
  4. Headaches or jaw aches. Anxiety and other mental illnesses can cause an individual to hold tension in their jaw and face. If sustained, this will lead to tension headaches and jaw aches which can be extremely painful.
  5. Getting sick often. When the stress hormone cortisol is elevated, it can compromise the immune system. This means that individuals who are experiencing anxiety or other mental health conditions that put strain on the brain and body are more at risk of getting sick.
  6. Heightened sensitivity. A high sensitivity to certain sensory inputs—including light, sound, touch, or smell—can be a sign of an underlying mental health condition, including ADHD, OCD and others.
  7. Substance abuse issues. Turning to substances is a common way that individuals attempt to subdue the symptoms of a mental health disorder. While substances provide some temporary relief, relying on them can lead to addiction and often make the underlying condition even worse.
  8. Memory problems. If an individual suddenly has trouble concentrating or remembering certain things, it can be a sign of a serious mental health disorder. Everyone goes through periods of stress when it may be difficult to think clearly, but a sustained period of memory loss is cause for concern.
  9. Irregular menstruation. The menstrual cycle is one indicator of mental state for women. It can respond to changes in hormones and mental or physical stress and cause a period to arrive early or late. On its own, this symptom usually isn’t worrisome, but if it is experienced in conjunction with other signs of mental illness, it may indicate an underlying issue.
  10. Overwhelming feelings of guilt or paranoia. Certain mental health disorders, such as OCD, can result in an individual being feeling overwhelmed by obsessive thoughts or paranoia. These thoughts and feelings may feel difficult or impossible to control or resolve.
  11. Muscle soreness. There are a number of reasons an individual may feel muscle soreness or pain, and most of them are normal and will resolve on their own. However, chronic pain and muscle soreness that won’t go away may be a sign that the body is holding onto stress or trauma.
  12. Excessive sweating. For most individuals, sweating is connected to the fight-or-flight response which happens when a threat is introduced. Overactive sweat glands could be a sign that an individual’s body is in a chronic state of stress related to an underlying mental health condition.
  13. Hair loss. Hair loss can be attributed to many causes, including aging and diet. However it can also be a sign of anxiety or another mental health disorder. Individuals suffering from mental illness may also be more inclined to pick at their hair or fingernails.
  14. Distraction. The sudden inability to concentrate or accomplish tasks is often a sign of a mental health condition. It is not uncommon for individuals struggling with mental health to have difficulty accomplishing goals or paying attention to the present moment.
  15. Lethargy or fatigue. Fatigue is different than simply feeling tired. The heavy, full-body sensation of chronic fatigue makes it feel impossible to accomplish daily tasks or feel motivation. This can often be a sign of an underlying mental health condition.

If you or someone you love is experiencing the symptoms above, please consult with a mental health professional.

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