Dear Dr. Mike,
My family suffers from a history of mental health issues, some minor to some more severe — my husband’s family does not share this same history. That said, we have a toddler and a preschooler and it has occurred to me that they might be at risk for inheriting mental health issues as they get older. Are mental health issues genetic, and, is a specific gender more prone to inheriting one? If so, at what age do symptoms typically present themselves?
Dear Concerned Parent,
Yes, mental illness does sometimes run in families and genetics do play a role. Twin studies and adoption studies have consistently demonstrated the significant role heritability and genetics play for being at risk to develop mental illness and neurodevelopmental conditions within the family. For example, research has shown that the concordance rate for monozygotic twins (identical twins) for Schizophrenia is between 40% and 60%; meaning that if one twin has schizophrenia there is about a 50% likelihood that the other twin will also share the diagnosis. Autism, Bipolar disorder, ADHD, Major Depressive Disorder, and Panic Disorder are some of the other mental health disorders that have a strong genetic reality.
But having a genetic predisposition for a certain mental condition does not mean that the condition will develop; it just means that certain individuals will be more susceptible to the condition due to their genetics. If genes explained everything, then the concordance rate for a condition (e.g., Schizophrenia) for identical twins would be 100%. Several factors in addition to genetics contribute to the development of a mental health condition or disorder — prenatal damage, substance abuse, infections, stress, abuse (emotional, physical, or sexual), poor nutrition, brain damage/defects, exposure to toxins, and other traumas (e.g., early parental loss, divorce, and neglect). Thus, if an individual has a genetic predisposition for a mental illness along with other concerning external or environmental stressors or factors, that individual would then be considered to be at an increased risk for developing a condition.
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Regarding gender, the research has shown that some conditions occur more in females than males and vice versa. When it comes to ADHD and Autism, males are diagnosed with those conditions at much higher rates than females — boys are about 3 times more likely than girls to be diagnosed with ADHD, and boys are 5 more times likely than girls to have an Autism Spectrum Disorder. Men also have higher rates of Alcohol Dependence and Substance Abuse and Antisocial Personality Disorder, while Major Depressive Disorder is twice as common in women. Women are also shown to have higher rates of certain types of Anxiety Disorders than men. The research has not shown significant gender differences for several other disorders, such as Bipolar Disorder or Schizophrenia.
Regarding the age of onset, some conditions develop early in life and others not until much later. For example, children with Autism Spectrum Disorders have been diagnosed as young as 2 years old, and most are diagnosed between 4- and 5 years old. The average age for ADHD is 7 years old. This is because problems associated with Autism and ADHD become more apparent with the increasing demands and challenges of life (e.g., attending school). Schizophrenia is typically diagnosed in the early 20s with signs sometimes being apparent in adolescence. Adolescents tend to have higher rates for Depression, but Depression and Anxiety can occur at any stage of life.
You write that you have a toddler and preschooler who have a history of unspecified mental illness on your side of the family. While you are a good mother to wonder about your children with your history, again, remember that genes alone do not determine whether or not one will develop a mental health condition. Rather than worrying about what could happen, I would instead recommend that you focus your energy on what you can do to help your children develop a strong psychological core and foundation. By providing a loving and secure home environment for your little ones with exposure to various social, physical and learning/enrichment concentrated activities; you will be doing what you can to ensure their future well-being.
And also remember that the occurrence of social, emotional, learning, or behavioral problems does not necessarily mean that a condition or disorder is present, so please do not panic if your child experiences some struggles. Early intervention is advised should any problems arise. In my opinion, your pediatrician or family physician is the best professional to turn to for initial assessment and direction. Those professionals are well-trained to identify problems in development and then direct intervention and treatment to a child psychologist or child psychiatrist if needed.