SOD Chapter 1 - Subchapter 2 - schizophrenia.life

1.2 WHY DO SCHIZOPHRENIA AND SUBSTANCE USE DISORDERS OVERLAP?

Addiction and mental disorders like schizophrenia often occur together, and this overlap is unlikely due to random factors or measurement errors. It suggests a strong connection between the two conditions.

Discoveries in neuroscience and precision psychiatry are helping us understand how these two disorders develop together. The factors that make people more likely to develop psychiatric disorders are usually present from a young age, even if the symptoms don’t show up until later in childhood, teenage years, or adulthood.

No single cause: a look at key theories

While no single cause fully explains the comorbidity, several theories aim to explore why people with schizophrenia are more likely to develop substance use disorders.

One idea is the cumulative factors model, which suggests that challenges like poor cognitive, social, educational, and vocational functioning, combined with poverty, victimization, and troubled social environments, increase the risk of substance use disorder among those with schizophrenia.

Another theory, known as the self-medication hypothesis, proposes that individuals with schizophrenia may turn to substances like tobacco, cannabis, alcohol, or opiates to reduce certain symptoms or minimize the undesirable effects of treatment. This behavior might be driven by the intense emotional states often experienced, such as fear, despair, and agitation.

The diathesis-stress model, or “two-hit” theory, explains that schizophrenia can develop when someone with a biological vulnerability faces environmental stress, including substance use.

The reward deficiency syndrome theory points to a possible dysfunction in the brain’s reward system, which could lead people with schizophrenia to seek out substances for a sense of pleasure or relief.

These theories offer different perspectives, but aren’t mutually exclusive, and might all help understanding the complex relationship between schizophrenia and substance use disorders.

Detrimental Factors are characteristics or conditions that increase the risk of developing substance use problems in a person with schizophrenia.

*Factors*	*Description*
Genetic Susceptibility	There’s evidence indicating a genetic predisposition for both schizophrenia and substance use disorders, that may increase vulnerability to developing either or both conditions.
Neurobiological Imbalances	Alterations in brain pathways and chemicals, like dopamine, glutamate, serotonin, and others, play a role in both schizophrenia and substance use disorders. These changes might explain why these conditions often occur together.
Early Substance Exposure	Substance use during adolescence or early adulthood, even preceding schizophrenia symptoms, can worsen the illness and elevate the risk of substance use disorder.
Self- Medication	Some individuals with schizophrenia may turn to substances to alleviate distressing symptoms like cognitive, negative, and positive symptoms (hallucinations or delusions), potentially leading to substance use disorder as a form of self-medication.
Socioeconomic Challenges	Poverty, unemployment, homelessness, and social isolation, prevalent among individuals with schizophrenia, can increase substance use as a coping mechanism or for socialization.
Stigma and Exclusion	Schizophrenia-associated stigma may result in social exclusion and discrimination, driving individuals towards substance use as a means of coping or rebellion.
Substance Accessibility	Individuals with schizophrenia may have easier access to substances due to factors like homelessness, involvement in street culture, or lack of supervision, heightening the likelihood of substance use initiation and escalation.

Understanding the factors that influence substance use problems in people living with schizophrenia is crucial for helping prevent and address these issues. By looking at various influences that can increase the risk or protect against substance misuse in schizophrenia, we can better support them in facing the challenges.

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