Addiction & Mental Health

Addiction and mental health disorders often go hand in hand: millions of people suffer from these so-called “concomitant” disorders, yet only a minority receive adequate support

Mental health

Improving addiction care services in adolescence should be a priority objective to adequately prevent mental health disorders – Photo by  Pier Monzon in Unsplash


Dual diagnosis, co-morbidity, concurrent disorders, all of these three terms are used to qualify two medical conditions that co-exist in the same person, for example a mental disorder and a substance use disorder. Many people who suffer from addiction also have an underlying mental health problem. While one condition may exacerbate the symptoms of the other, there is no evidence that one is necessarily caused by the other.

Several factors may explain the coexistence of substance use disorders (SUDs) and other mental health disorders:

  • Certain risk factors may contribute to both SUDs and other mental disorders. Some families are more affected by both conditions, implying that certain genes may be a risk factor. Environmental factors, such as stress or trauma, can cause genetic changes that are passed on from generation to generation, which could contribute to the onset of a mental disorder or substance use.
  • Mental disorders can contribute to substance use and SUDs. People living with a mental disorder such as depression, anxiety or post-traumatic stress disorder are more likely to use alcohol or other drugs to relieve their symptoms (self-medication). However, while these substances may help temporarily, over time they only make things worse.
  • Substance use and SUDs can contribute to the development of other mental disorders. Substance use can trigger changes in brain structure and function that make people more prone to developing a mental disorder.

Chronic pathologies

Substance use disorders and other mental disorders are chronic brain conditions or pathologies. In other words, when a person has an addiction, the functioning and structure of the brain system are profoundly altered. These complex disturbances lead to a loss of control over one’s behaviour, which is why addiction is described as a neurological disease.

The brain disturbances associated with substance use occur in the same areas of the brain affected by depression, anxiety, schizophrenia and bipolar disorder. This is why concurrent SUD/mental disorders are common.

A period at risk, adolescence

Adolescence is most often characterised by a period of integration into the circle of friends and distancing from parents. It is also a time of curiosity, risk-taking and challenge. It is during this period that many begin to use psychoactive substances, both legal and illegal, such as alcohol, tobacco and cannabis.

During this period, the brain is very sensitive to stress and the impact of psychoactive substances. Research has shown that during adolescence the brain is in a unique state of transition and shaping, making it more vulnerable to the neurotoxic effects of substances and to the onset of mental illness. Regular consumption of alcohol, tobacco and cannabis during adolescence is associated with a wide range of short- and long-term health and social damage.

What’s more, consumption patterns and potentially addictive practices among teenagers are constantly changing. Young people are turning to new drugs and new addictive behaviours, such as synthetic drugs (new psychoactive substances) and addictions to video games or gambling. These developments pose major challenges, not only from a public health perspective, but also in terms of adapting prevention and treatment programmes.

Cannabis use during adolescence


hoja cannabis iconoDespite being less dangerous than other substances, cannabis is far from harmless. Frequent and regular use during adolescence can damage brain development, particularly for those who start using at an early age. Studies report cognitive difficulties linked to memory, concentration and reading, and arithmetic skills. People who use cannabis are also more likely to dropout or have difficulties at school.


Studies have established a link between regular cannabis use and the development of psychiatric symptoms or disorders (e.g. schizophrenia and other psychotic disorders, depressive and anxiety disorders, suicidal ideation). The risk of developing a mental health problem is particularly high among people who began using cannabis in adolescence and among users with a personal or family psychiatric history. Daily use in adulthood is associated with a higher incidence of mental illnesses such as schizophrenia. However, the association between cannabis use and mental health disorders does not imply that cannabis is the direct or sole cause.

Relation with traumas

People who have suffered physical or emotional trauma are much more exposed to substance use disorders. In the United States for example, one in five veterans of the Iraq and Afghanistan conflicts report post-traumatic stress disorder or major depression. In addition, half the veterans diagnosed as suffering from post-traumatic stress disorder also have a concomitant SUD problem.

A complex diagnosis

Concurrent disorders are sometimes difficult to diagnose. Their symptoms are often complex and can vary in severity. It often happens that the people concerned are admitted for treatment for one disorder, while the other disorder is not even discussed. This is because the symptoms are very similar and often overlap.

Mental health problems and substance use disorders (or other addictions) may have similar biological, psychological and social components.

Incomplete diagnoses may also be linked to inadequate training or screening. The need for reliable systems must be emphasised, as the consequences of undiagnosed, untreated or inadequately treated concurrent disorders can increase the risk of suicide, imprisonment and even social exclusion.

Treatment of co-morbidities

Research shows that concurrent disorders need to be treated at the same time. In fact, for the best results, it is recommended that people suffering from both an addiction and a mental health problem receive integrated treatment. With these types of treatment, doctors and other therapists can address and treat both disorders at the same time. This often results in lower treatment costs and better outcomes for patients.

Finally, early detection and treatment of these disorders can greatly improve a person’s recovery and quality of life. However, it is important to note that people suffering from both an addiction and another mental illness often present symptoms that are more persistent, more severe and more resistant to treatment than patients suffering from just one of these disorders.

Sources: National Institute of Mental Health, World Health Organization.