In mental health clinics, clinicians are increasingly hearing stories that do not fit typical profiles. Young patients describe episodes of intense anxiety, persistent insomnia, or perceptual disturbances that are difficult to explain. In some cases, symptoms appear after a weekend; in others, weeks or months later. In the end, the same context often emerges: chemsex — the use of drugs for sexual purposes — with psychological consequences that also warrant attention in clinical practice.

The term chemsex, a contraction of the English “chemical sex,” describes the intentional use of psychoactive substances such as methamphetamine, gamma-hydroxybutyrate (GHB) or gamma-butyrolactone, mephedrone, and other synthetic cathinones — often in combination — to facilitate or intensify sexual encounters that may last for hours or even days.

Until recently, healthcare responses to these practices focused primarily on sexual health, aiming to reduce the risk for HIV transmission and other sexually transmitted infections, as well as prevent acute complications such as overdose or toxicologic emergencies. Today, however, evidence broadens the focus and clearly shows that the risks extend to mental health. Persistent anxiety, depression, suicidal ideation, psychotic episodes and substance use disorders are increasingly reported in the scientific literature.

However, the psychological impact is not uniform; it depends directly on patterns of use. Intravenous injection during sexual encounters — known as slamsex — weekly participation and polysubstance use are all associated with a greater burden of psychological distress.

From Chemical Pleasure to Psychological Distress

A cross-sectional study published in Healthcare (2023-2024) involving men who have sex with men in the UK found that 49.9% reported symptoms of anxiety and 27% reported symptoms of depression, with significantly higher rates among those who practiced chemsex weekly. These findings confirm a dose-response relationship between frequency of use and symptom severity.

Regarding suicidal behavior, a review published in Brain Sciences (2023) concluded that chemsex increases suicidal ideation, suicide attempts and psychological distress, particularly among individuals who use intensively or who practice slamsex. Therefore, intensity of use and route of administration are key variables in suicide risk.

Other studies expand the impact to psychotic symptoms, delusional thinking, social isolation, personality changes and difficulties in academic or professional settings. Acute psychosis and delirium have been described in association with methamphetamine, mephedrone and other cathinones, especially among individuals using high doses, engaging in prolonged consumption or injecting intravenously.

In this context, chemical pleasure may transform into intense psychological distress, the severity of which depends not only on the substances used but also on how, when, and how often they are consumed. These findings reinforce the need to place mental health at the center of chemsex-related care.

Chemsex-Specific Drugs and Their Effects

Among the substances most frequently used for their sedative, anxiolytic, and sexually stimulating effects are GHB and its precursors. The use has increased in recent years and, according to the literature, dependence can develop within weeks. From a psychiatric perspective, withdrawal syndrome is particularly relevant and is characterized by severe anxiety, psychomotor agitation, tremor, confusion and memory disturbances, with a risk for progression to delirium with hallucinations and psychotic symptoms in more than 50% of cases if not treated appropriately.

GHB detoxification is described as complex and potentially dangerous, often requiring moderate doses of benzodiazepines to control withdrawal. A high prevalence of delirium and the need for admission to ICUs have also been reported, even when treatment is appropriately administered, underscoring the severity of this condition.

In the case of crystal methamphetamine, studies conducted among men who have sex with men show a broad impact on mental health, including higher rates of depressive symptoms, anxiety, somatization and posttraumatic stress disorder compared with the general male population, with risk increasing as dependence worsens.

Chronic use is also associated with paranoid ideation, hallucinations, overt psychosis and an increased risk for persistent psychotic disorders. Suicidal ideation and behavior have also been reported, particularly in the context of polysubstance use and prolonged sleep deprivation — a frequent factor during extended chemsex sessions.

Synthetic Cathinones and Their Effects

Synthetic cathinones such as mephedrone (4-MMC) and its derivatives (3-MMC) have been consistently linked to acute and subacute psychiatric symptoms in chemsex contexts. Clinical case series report intense agitation, anxiety, insomnia and sudden-onset low mood, sometimes accompanied by suicidal thoughts. Approximately 40% of cases show psychotic symptoms, mainly paranoid delusions and hallucinations, typically following weeks of heavy use.

From a pharmacodynamic perspective, a study published in Neuropsychopharmacology (2024) examining 3-MMC in healthy volunteers demonstrated a dose-dependent psychostimulant profile, including increased heart rate and blood pressure, along with mild psychotomimetic effects such as derealization, depersonalization, and perceptual changes.

Although these effects were mild and transient under controlled conditions, reviews of real-world chemsex use indicate that cathinones are associated with severe anxiety, acute psychosis and suicidality, particularly when use is intense, prolonged, or combined with other substances.

Ketamine and Other Drugs in Chemsex

Ketamine presents a distinct profile among substances used in chemsex. Its dissociative effects — including altered perception, depersonalization, feelings of detachment from the environment and changes in consciousness — have attracted clinical interest for their potential antidepressant effects under controlled conditions. However, in recreational use, these same mechanisms are associated with significant psychiatric risks.

A review published in Therapies (2025) examining polysubstance use found that ketamine is frequently used as an adjunct to induce relaxation or reduce anxiety. However, it was also associated with distressing depersonalization episodes, mental confusion and worsening depressive symptoms. At high doses or with chronic use, the risk for cognitive impairment and psychotic symptoms increases.

Ketamine is often combined in chemsex settings with cocaine and 3,4-methylenedioxymethamphetamine (stimulants), as well as benzodiazepines and alcohol (central nervous system depressants). A clinical guideline focused on chemsex and mental health (2025) warns that such polysubstance use is linked to emotional lability, anxiety, post-use depressive symptoms (the so-called “crash”), sleep disturbances and memory problems. In some cases, paranoid ideation and psychotic symptoms also emerge, particularly when stimulants and depressants are combined in the same episode.

Another review published in the Journal of Medical Case Reports (2025) describes a recurrent temporal pattern: the euphoria or disinhibition of the “high” is followed by marked mood declines. It is during these “crashes” that feelings of emptiness, loneliness and guilt appear — factors that may contribute to both the onset and persistence of anxiety and depression. This emotional fluctuation is a key component of the psychological distress associated with chemsex.

Patterns of Use and Psychiatric Risk

Beyond the specific substances involved, evidence consistently shows that not all chemsex patterns carry the same level of psychiatric risk. In a Spanish cohort study (2024), injection of drugs in sexual contexts (slamsex) was specifically associated with a higher likelihood of suicidal ideation, suicidal behavior and psychotic episodes compared with similar practices without injection. The study concluded that route of administration is an independent determinant of psychiatric risk.

Frequency also matters. Cross-sectional and longitudinal studies show that frequent participation — for example, weekly — is associated with a greater likelihood of anxiety and depressive symptoms compared with occasional participation, demonstrating a clear risk gradient.

Finally, the literature emphasizes that polysubstance use multiplies the risk for acute psychiatric complications, including psychosis, delirium, and panic attacks, and is associated with worsening of preexisting mental disorders, creating more complex and vulnerable clinical scenarios.

Considering all available evidence, it is clear that these patients should be evaluated not only from the perspective of substance use or the obvious physical risks. Mental health assessment must be systematically integrated into care. Such evaluation should consider route of administration, intensity of use and substance combinations, because chemsex — far from being solely a sexual or infectious issue — poses clear challenges in clinical practice and in the prevention of psychological and psychiatric disorders.

This story was translated from El Medico Interactivo, part of the Medscape Professional network.