Dual diagnosis is a term used to describe someone suffering from both a mental illness and a drug addiction. Those suffering from drug addiction often also suffer from a mental illness, and vice versa. According to the National Bureau of Economic Research, there is a “definite connection between mental illness and the use of addictive substances.”

They further state that those with a mental illness consume:

  • 40% of all cigarettes
  • 38% of all alcohol
  • 44% of cocaine

The statistics indicate that the presence of any mental illness is often a precursor to drug addiction. Many psychologists and specialists also believe that the usage of drugs be a major cause in the development of a mental illness. The causation is a two way street, making dual diagnosis cases difficult to understand and treat.

Doctor and patientUnfortunately, the Substance Abuse and Mental Health Services Administration (SAMHSA) has found that 55.8% of people suffering from a dual diagnosis, also known as co-occurring, fail to receive treatment for either disorder.

They’ve also found that only 7.4% of dual diagnosis patients actually receive treatment for both conditions.

A Difficult Situation to Understand

Due to the correlation between mental illness and drug abuse, it’s difficult for those close to the patient to understand what exactly is going on. It’s even difficult for the professionals to catch and diagnosis a co-occurring condition.

Often times, a drug addiction is treated without addressing the mental illness, or the other way around. Studies into this complicated situation are ongoing, but many mental health professionals have agreed on a handful of theories that can help those concerned understand dual diagnosis.

  • Using heavy drugs during teen years can often lead to issues with cognitive and social development, which becomes a mental illness later in life. This often results in a variety of anxiety disorders or depression.
  • Patients with mental illnesses are usually prescribed medications that have various unpleasant side effects. Some of these patients will turn to drugs to help relieve these side effects. As an example, some bipolar medication will cause nausea. The patient may then turn to marijuana to help deal with the nausea.
  • unhappy man thinkingYears of chronically abusing certain drugs can lease to the development of a mental illness. Ecstasy is most commonly known to permanently alter the way the brain controls moods and emotions. This can result in depression, bipolar or anxiety.
  • Anyone who is genetically at risk for a mental illness will increase that risk with substance abuse. Consistent usage of heavy drugs can be enough to develop a mental illness if there is a predisposition to it.

How to Spot a Dual Diagnosis in Loved Ones

It’s difficult for mental health professionals to accurately assess a dual diagnosis situation. This makes it even more difficult for those who are simply concerned about someone they love. The only real way to confidently diagnose a co-occurring condition is by an in-patient stay at a professional treatment facility.

However, those concerned can keep an eye on the behavior of their loved ones. If they have a confirmed mental illness or drug addiction, keep an eye out for signs of the other occurring. If neither have been diagnosed or treated, but you suspect that they might have a dual diagnosis, advise that they seek a consultation with a qualified mental health professional.

Seeking treatment can help end a long string of self-destructive behaviors set in motion by the co-occurring condition.


  1. About Co-Occuring, Substance Abuse and Mental Health Services Administration, http://media.samhsa.gov/co-occurring/
  2. Marie Bussing-Birks, Mental Illness and Substance Abuse, http://www.nber.org/digest/apr02/w8699.html