The Link Between Schizophrenia and Substance Use Disorder

Schizophrenia is a serious mental health disorder that affects less than 1% of the population.^1,2 However, it is estimated that 47% of people living with schizophrenia struggle with substance use disorders.²

This article will explain what schizophrenia is and its risk factors, signs and symptoms of schizophrenia, and treatment options for you or someone you love who may be living with co-occurring schizophrenia and addiction.

What Is Schizophrenia?

Schizophrenia is a serious mental illness that involves severe impairments in a person’s thought process, feelings, and behavior.³ People may appear to have lost touch with reality, and they can experience significant distress from their symptoms, which can also be distressing to those around them.³

Schizophrenia is just one of several psychotic disorders, which also includes schizophreniform disorder, schizoaffective disorder, and related conditions. While each psychotic disorder has its own diagnostic criteria, this group of disorders shares certain features, including one or more of the following:¹

• Delusions (firmly held false beliefs based on incorrect inferences about reality).
• Hallucinations (seeing, hearing, smelling, tasting, or feeling things that aren’t there).
• Disorganized thinking and speech.
• Grossly disorganized or abnormal motor behavior (including catatonia).
• Negative symptoms (e.g., a reduction or absence of normal emotions, behaviors, and functions).

Risk Factors for Schizophrenia

While schizophrenia isn’t linked to a single cause, people with certain risk factors may have a higher likelihood of developing the disorder.³ Some risk factors include:³

• Genetics. Schizophrenia can run in families, and there are different genes that may contribute to the disorder, but having a family member with schizophrenia doesn’t mean that you will develop it, too.
• Environment. Different factors, such as poverty, stressful or dangerous surroundings, exposure to viruses, and poor nutrition before birth, may play a role.
• Brain structure and function. People with schizophrenia may have differences in brain structure and size, but more research is needed to understand how brain differences might
  impact the development of schizophrenia.

What Are the Signs and Symptoms of Schizophrenia?

While not everyone who lives with schizophrenia will experience the same symptoms or combination of symptoms, two or more of the following signs and symptoms of schizophrenia need to be present for six months for a diagnosis of schizophrenia:¹

Hallucinations

Hallucinations occur when a person sees, hears, smells, tastes, or feels something that seems real to them but is not actually present.¹

Delusions

Delusions differ from hallucinations and are related to a person’s beliefs. Delusions are often not true or seem irrational to others, and may include feelings of persecution, grandiosity, health concerns, etc.¹

Disorganized Thinking (Speech)

An individual with schizophrenia may have a way of thinking that is unusual or illogical that is typically inferred from their speech. For example they may answer questions in ways that are unrelated to the query, speech patterns may be incomprehensible, or they may switch from one topic to the next rapidly.¹

Disorganized or Abnormal Behavior

This symptom generally manifests as unusual and often unpredictable physical actions that can include: childlike silliness, unpredictable agitation, and catatonic behaviors including inappropriate or bizarre postures, purposeless or excessive movement, staring, grimacing, and lack of verbal or motor responsiveness.¹

Negative Symptoms

Unlike the other more noticeable positive symptoms commonly associated with schizophrenia, negative symptoms represent a decrease or absence of typical functions. Two negative symptoms particularly prominent in schizophrenia include diminished emotional expression and a decrease in motivated self-initiated purposeful activities. Other negative symptoms include a flat affect, reduced speech, lack of initiative, apathy, and difficulties maintaining relationships.¹

Is There a Link Between Schizophrenia and Addiction?

There is a strong link between schizophrenia and substance misuse and addiction. Up to half of people have at least one substance use disorder in their lifetime.^2,4 Cannabis is linked to an earlier onset of schizophrenia and more severe positive symptoms among individuals with schizophrenia.⁵

Substance misuse in people with schizophrenia can contribute to worsened disease course and lack of medication adherence. It can also lead to shortened mortality and an increased likelihood of deleterious health and functional outcomes, including a higher risk for self-destructive and violent behaviors, victimization, suicide, housing instability, poor physical health, cognitive impairment, employment problems, legal issues, and unstable social relationships.⁴

Treatment for Schizophrenia & Addiction

People who are struggling with co-occurring disorders, including psychotic disorders like schizophrenia and addiction, can often benefit from integrated treatment that addresses both conditions.² Addressing substance use disorders and schizophrenia concurrently through integrated treatment yields more positive results for managing symptoms and improving overall well-being than single interventions and is the current standard of care.⁵ It’s important to treat the SUD and psychotic disorder simultaneously because substance misuse can significantly worsen symptoms of schizophrenia.²

Antipsychotic medication helps to address positive symptoms of schizophrenia, such as delusions and hallucinations, and is typically combined with behavioral therapies to treat SUD, such as:²

• Integrated cognitive behavioral therapy (CBT).
• Group therapy.
• Contingency management.
• 12-Step facilitation.
• Motivational enhancement.
• Motivational interviewing.
• Assertive Community Treatment (ACT).

American Addiction Centers (AAC) is a leading provider of co-occurring disorder rehab, with treatment centers located across the U.S. Please call us at to speak to a caring admissions navigator about your treatment options.