Mental disorders or illnesses tend to run in families. Last year a study published in the Journal of Family Psychology revealed another familial connection. People with a sibling suffering from a mental illness or disorder are more have a higher risk of developing depression at some point in their lives.

"So little is known about the impact that a person with low IQ or mental illness has on the psychological and social development of his or her siblings, especially beyond childhood," said Julie Lounds Taylor, Ph.D., the study's lead author. "Our findings highlight the need for families of the mentally ill, specifically siblings, to be more aware of their own mental health needs throughout their lifetimes."

According to the National Institute of Mental Health, about 26.2 Americans over age 18 suffer from a diagnosable mental disorder; based on current census data that amounts to over 80 million people. Mental disorders include depression, bipolar disorder, schizophrenia, eating disorders, and anxiety disorders such as obsessive-compulsive disorder and post-traumatic stress disorder.

Lounds and her team of researchers analyzed data on 351 people from a 46-year study who had at least one sibling with a mental disorder, and compared it to data on 791 people whose siblings did not have a mental illness.

They found that people whose siblings had a mental illness were 63 percent more likely to experience a bout of depression in their lifetime. These depressive episodes were characterized by periods of two weeks or longer with symptoms such as feeling lonely, crying or loss of appetite.

Furthermore, having a brother with a mental disorder increased the likelihood of having a lower level of psychological wellbeing. The researchers suggested that genetics wasn't the only factor at play, but also the social relationship.

Researchers also discovered that people who had a sibling with a low IQ - 85 or below - were 18 percent more likely to live near their sibling than people in the comparison group. However, they were rather emotionally detached from their disabled sibling.

On the positive side, having a mentally disabled sibling did not interfere with a person's chances of getting married or having children.

Early Symptoms of a Mental Disorder

How do you know if you or your sibling has a mental disorder? The World Health Organization (WHO) explains that these health conditions produce patterns of thinking, mood, or behavior that do not hold with cultural beliefs and norms.

Mental disorders are associated with a wide variety of symptoms, such as:

  • Emotional symptoms, for instance feeling anxious, sad or scared.
  • Cognitive symptoms, such as memory or concentration problems.
  • Behavioral symptoms, for instance aggressive behavior or substance abuse.
  • Physical symptoms, such as headaches, insomnia, or appetite changes.
  • Perceptual symptoms, such as hearing voices or seeing things other people cannot see.

If you or your sibling experiences one or more of these symptoms for a period of time, you should seek medical attention, advises the WHO. There are many treatments available that can effectively treat mental disorders, including depression.


American Psychological Association press release, "Siblings of Mentally Disabled Face Own Lifelong Challenges, According to Researchers."