November 11, 2025
Substance use and mental health – explore co-occurring disorders, mechanisms, conditions from depression to psychosis, and integrated care.
Substance use and mental health are deeply intertwined, often forming a bidirectional relationship that amplifies risk, complicates treatment, and challenges recovery. In this article, we explore substance use and mental health — how psychoactive substances (including alcohol, cannabis, opioids, stimulants) impact, exacerbate or co-occur with mental health conditions such as depression, anxiety, ADHD, OCD, schizophrenia, borderline personality disorder (BPD), psychosis and eating disorders. We will review current research, clinical implications, mechanisms, and provide guidance for integrated, evidence-informed care.
Research consistently shows that individuals with substance use disorders (SUDs) often have a co-occurring mental health diagnosis, and vice versa. According to the National Institute of Mental Health (NIMH), substances and other mental disorders can interact because environmental factors, genetics and brain changes can predispose to both.
For example, nearly 19.4 million U.S. individuals reported both a substance use disorder and a mental-health condition in a given year.
A clinician must always consider the possibility of dual-diagnosis—that is, substance use and mental health disorders occurring simultaneously—because treatment strategies must accommodate that complexity.
Because the direction of causality can vary (mental health disorder → substance use; substance use → new or worsened mental health disorder; or both sharing common risk factors), assessment must be comprehensive.
Substance use may both mask and worsen depressive symptoms. Chronic alcohol or drug use can alter neurotransmitter systems (serotonin, dopamine) and increase vulnerability to major depressive episodes. Brain research shows that substances interfere with neural circuits of mood regulation.
Clinically, someone presenting with persistent low mood, loss of interest, and substance use (e.g., heavy alcohol use) should be screened for both a depressive disorder and a substance-use disorder.
Patients often report using substances (alcohol, sedatives, cannabis) in attempts to self-medicate anxiety. However, evidence shows that while there may be short‐term relief, longer‐term frequent use increases anxiety, panic symptoms or generalized anxiety disorder (GAD).
The paradox: what begins as calming may, through tolerance and withdrawal, worsen baseline anxiety.
For individuals with Attention‑Deficit/Hyperactivity Disorder (ADHD), impulsivity and sensation-seeking increase the risk of initiating substance use and progressing to problematic use. Executive dysfunction may impair monitoring of use and increase risk of dependence.
Once substance use begins, ADHD symptoms may worsen (e.g., poor concentration, disrupted sleep) and interfere with academic or occupational functioning. Studies show distinct profiles of substance use among ADHD populations.
In treatment contexts:
Though less studied, some individuals with OCD may use substances to reduce distress caused by intrusive thoughts or compulsions. The problem: substance use may dampen insight or reinforce avoidance behaviours, complicating OCD treatment.
Treatment must carefully assess co-occurring substance use, as standard exposures/response prevention require cognitive clarity and motivation.
Patients with Borderline Personality Disorder frequently present with emotion-dysregulation, impulsivity and unstable relationships—all risk factors for substance misuse. Indeed, substance use disorders are common in BPD populations and may exacerbate self-harm, affective swings and therapy non-adherence. Clinicians should integrate DBT (Dialectical Behaviour Therapy) skills training with substance-use relapse prevention.
One of the most critical intersections is that between substance use and psychotic disorders. Heavy use of cannabis, methamphetamine or hallucinogens is linked to higher risk of psychosis and earlier onset of Schizophrenia in vulnerable individuals.
Substances can trigger acute psychotic episodes, and in schizophrenia patients, co-occurring SUD often leads to worse outcomes: more hospital admissions, poorer adherence, higher relapse rates.
Best practice:
Individuals with eating disorders (e.g., anorexia nervosa, bulimia) may use substances (stimulants, laxatives, alcohol) for weight control, appetite suppression or mood modulation. The interplay of eating pathology, mood, impulsivity and substance use creates a complex clinical picture.
Substance use in this context can impede recovery (nutritional rehabilitation, cognitive behavioural therapies) and increase risk of medical complications. Assessment and treatment must be integrative: a specialist team addressing eating, mood and substance use.
Early initiation of substance use—especially during adolescence when brain maturation is ongoing—can interfere with brain development, cognition, executive function and reward processing. This is especially relevant for youth with comorbid mental-health diagnoses (e.g., ADHD), where substance use may compound risk for long-term functional impairment. Prevention strategies must emphasise delaying initiation, reducing frequency and limiting high-risk substances.
The relationship between substance use and mental health can be explained via several mechanisms:
Contemporary research emphasizes the need for integrated care models that simultaneously address substance use and mental health. For example, a 2024 paper in Journal of Clinical Medicine found integrated treatment improves engagement, reduces use and improves mental-health outcomes.
Key practice recommendations:
Approximately 50% of individuals with a severe mental disorder also have a comorbid substance-use problem. The societal burden is substantial: increased hospitalisations, lost productivity, greater morbidity and mortality. Prevention and early intervention are essential.
Public-health efforts should include:
At Integrative Psych, our multidisciplinary teams in Chelsea (NYC) and Miami specialize in advanced, evidence-based mental health care that integrates psychotherapy, medication management, digital biomarkers and substance-use screening. When substance use and mental health concerns overlap—as they often do—our clinicians deliver personalized, integrative treatment pathways to address mood, attention, cognition, personality, self-regulation and addiction concurrently. If you or someone you love is navigating the dual challenge of mental health symptoms and substance use, we invite you to explore how our team of clinical experts can collaborate with you on a tailored recovery journey.
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