Anxiety and Feelings of Unreality

Over the past eight months ‘Petter’ has struggled with increased anxiety and an altered experience of himself and the world. His symptoms developed gradually after a chaotic experience with psilocybin (mushrooms/truffles) in Amsterdam with friends. During the trip, he experienced an overwhelming loss of control and fear of dying, in an unsafe public setting where he felt helpless. His group of friends responded in a belittling way when he tried to share his experience, and he has therefore kept his difficulties hidden. After the trip, he was frightened by a strange sensation of not being present in his own body and of the world seeming dreamlike – as if he were an actor in an artificial reality. This disconnected state occurs periodically and varies in intensity, often exacerbated by stress and poor sleep. He is troubled by nervousness, racing thoughts and excessive self-monitoring in social situations. He feels distressed and increasingly hypervigilant toward his inner experiences.

Persistent difficulties after psychedelics often occur in connection with particularly distressing experiences. In a large study of psilocybin users about their most difficult experience with the drug, 39% reported that the experience was among the 5 most challenging in their life. Among those who still had difficulties more than 1 year later, 7.6% had sought psychological or medical help (Carbonaro et al., 2016). A representative population-based study found that 8.9% of users of classical psychedelics reported impaired functioning for more than a day after a difficult experience (Simonsson et al., 2023). Among people with persistent difficulties, a large study found that the majority had experienced problems for more than a year and that greater distress during the psychedelic experience predicted longer duration and increased intensity of symptoms (Evans et al., 2023). At the same time, difficult experiences do not necessarily lead to negative outcomes, and many report that they also had positive after-effects (Carbonaro et al., 2016; Johnstad, 2021). In line with this, the field has increasingly adopted the term ‘challenging experience’ instead of the more negative ‘bad trip’. A challenging experience suggests the possibility of personal growth rather than a primarily nightmarish or harmful episode, but critics argue that it obscures negative effects and risk (Strassman, 2018).

The content of difficult experiences varies, but common themes are loss of control, helplessness, painful memories, a sense that others mean harm, and existential or spiritual distress (Barrett et al., 2016; Schutt et al., 2025). We have recently translated and validated the ‘Challenging Experience Questionnaire’ (CEQ) into Norwegian, which measures difficult/challenging experiences across seven factors: fear, grief, physical distress, fear of losing one’s mind, isolation, death and paranoia (Andersen et al., 2025). A recent survey of a convenience sample of Norwegian psychedelic users found a weak negative association between high levels of challenging experience (measured with the CEQ) and subjective well-being (Tunstad et al., 2025). Furthermore, factors such as emotional resolution (‘breakthrough’) were associated with positive effects from challenging experiences, suggesting that the outcome of such experiences is influenced by how they are processed as they unfold.

In recreational contexts, challenging experiences may occur in settings that do not allow for adequate support during this vulnerable state. Patients have described highly distressing situations, such as suddenly re-experiencing memories of abuse in a crowd at a music festival. The risk of overwhelming and confusing experiences increases if the user does not know the substances’ unpredictable effects and their tendency to increase receptivity to external stimuli (Haijen et al., 2018). Other risk factors are high doses, combining different substances, psychological vulnerability and younger age (Carbonaro et al., 2016; Simonsson et al., 2023). A recent longitudinal study found a positive association between negative psychedelic experiences and subsequent increases in depressive symptoms. This association was strongest when the use took place in a ‘risky setting’, characterized by a negative mental state and lack of psychological support (Simonsson, Hendricks, Swords et al., 2025). At the same time, distressing experiences and persistent problems can occur despite good preparation, which stands in contrast to how these substances are often portrayed as inherently therapeutic in user communities (Holm et al., 2023). Several people have reported condescending or dismissive responses that reinforce their burden, where negative outcomes are ascribed to personal shortcomings, such as having ‘misunderstood the message’ or lacking aptitude for personal development.

The symptom pattern we most often see is a combination of anxiety, sleep difficulties and dissociative phenomena. Many describe strong physiological arousal and problems falling asleep afterwards, sometimes accompanied by panic attacks. The risk of this is higher if the psychedelic experience was frightening, but sometimes there is no clear link to characteristics of the experience. We do, however, often see that the experience becomes mentally intrusive, even if the memories are fragmented. This can involve specific sequences that have been etched into memory, intense bodily sensations, a feeling of acute loss of control or horrific inner images. In our experience, the intensity of symptoms fluctuates, with shifting complaints, confusion and sudden anxiety. Both our clinical experience and the literature suggest that anxiety occurs more frequently than depression (Robinson et al., 2025; Simonsson et al., 2023), with the latter emerging in the context of prolonged struggle with symptoms and compounding life stressors.

A frequent phenomenon is the sense of being mentally detached from one’s body and identity, including periods of global unreality (Evans et al., 2023; Robinson et al., 2024). Depersonalization and derealization (DP/DR) refers to persistent feelings of disconnection, where the self and surroundings feel artificial or devoid of meaning. Reality testing remains intact, but the person may ruminate excessively about how existence feels dreamlike or inauthentic (Ciaunica et al., 2022). It is paradoxical that substances that usually enhance awareness of the present moment can trigger disconnection, but it is known that DP/DR can arise when the psychological and neural systems that underpin our usual sense of self and reality are disrupted (Gatus et al., 2022). The phenomenon is also associated with stress, sleep deprivation and exhaustion, all of which can occur after psychedelic use, and it is more common among younger people (Yang et al., 2023) – which overlaps with the main user group. When DP/DR is long-lasting and distressing, it constitutes a condition in its own right, but it can also be one aspect among other difficulties.

An observation from our patients is that anxiety and DP/DR following psychedelics often lead to a kind of ‘mental health anxiety’. Many fear losing their grip on reality, ‘going crazy’ or developing schizophrenia. In most cases, it is unlikely that the person is becoming psychotic, and it is more reasonable to understand this as excessive worry about mental health. This often occurs after distressing experiences with altered states of consciousness, either during the acute drug effect or in the period afterwards. Many also grew up with exaggerated warnings, such as ‘taking LSD is like playing Russian roulette with your brain’, which can reinforce fears about severe mental illness. As with other forms of health anxiety, the person usually knows that the fear is disproportionate, but this insight weakens during episodes of increased anxiety. The anxiety can thus become highly uncomfortable, dominant and limiting.

Persistent Changes in Perception

‘Tarjei’ is in his early 20s and feels that life is on hold. Since high school, he has been troubled by altered visual perception, which began during a period when he took high doses of LSD several weekends in a row, often combined with cannabis, alcohol or MDMA. After an intense experience – during which he was also confronted by his parents – he noticed that visual effects from the LSD trip persisted in a sober state: objects that change size, ‘melt’ or ‘breathe’, afterimages from movements, bright halos, pixelated static and colorful flashes. This has been frightening, confusing and lonely. The intensity has subsided, but it is still present. The uncertainty about what has happened to him and whether he will ever get rid of it is a real burden. He has found a diagnosis that fits what he is experiencing and seeks information from online forums rather than health professionals. Knowing that others have the same condition has eased his fear of going crazy, but he feels hopelessness and ruminates a great deal about whether this will be a permanent handicap.

Persistent changes in perception after consumption of psychedelic substances is included in DSM-5 under the diagnosis ‘Hallucinogen Persisting Perception Disorder’ (HPPD). The condition is characterized by enduring alterations in sensory experience that differ qualitatively from the hallucinations or impaired reality-testing characteristic of psychotic disorders (Martinotti et al., 2018). HPPD prominently features altered visual impressions that partly overlap with the acute drug effect (Vis et al., 2021). The duration and severity of HPPD vary, but a subgroup reports symptoms that persist for years and cause significant distress (Martinotti et al., 2018; Vis et al., 2021). Users with HPPD whom we have met experience the symptoms as an impediment to normal functioning and psychologically burdensome.

The prevalence of HPPD is uncertain. In a self-selected survey, 4.2% of psychedelic users reported nearly constant visual changes that they perceived as unwanted and disturbing (Baggott et al., 2011), while 1.3% of users in a representative population-based study reported that they had received the diagnosis from a health professional (Simonsson, Goldberg, Chambers et al., 2025). At the same time, research suggests that transient and mild visual changes after psychedelics are common and rarely associated with significant distress or impaired functioning (Müller et al., 2024; Baggott et al., 2011). Perceptual changes during the acute psychedelic state are characterized by dissolved boundaries, increased sensory intensity and the experience of alternative patterns in familiar stimuli (Preller & Vollenweider, 2018), which is thought to be caused by reduced control and categorization in the brain’s processing (Carhart-Harris & Friston, 2019). Normally, this subsides in step with the drug effect, with only slight visual after-effects for a short period; in HPPD, however, a persistent and distressing alteration of consciousness occurs.

The term ‘LSD flashback’ was historically used to denote both visual changes and emotional re-experiencing and can be seen as a precursor to the current diagnostic label (Abraham, 1983; Horowitz, 1969). Long duration and marked visual effects may correspond to LSD as the triggering factor, as it may have an especially strong impact on visual systems, but HPPD also occurs with other psychedelics (Vis et al., 2021). Factors that likely increase risk are frequent use, polysubstance use, high doses and underlying sensory sensitivity (Halpern et al., 2018). The mechanism behind HPPD is unknown, but a central hypothesis is a reduced filtering of sensory data due to ‘cortical disinhibition’ (Vis et al., 2021). Overactivation in visual processing can produce unstable perception of objects, faces or lighting. The world can then be experienced as flickering, undifferentiated, distorted or full of colors, and, over time, sensitization to altered perception can amplify symptoms (Halper et al., 2018).

HPPD also shares features with other conditions. For example, persistent postural-perceptual dizziness (‘chronic subjective dizziness’) produces similar sensory changes (Popkirov et al., 2018), and during panic attacks, altered vision and feelings of unreality commonly occur (Hunter et al., 2003). Furthermore, in many cases, HPPD is accompanied by DP/DR and anxiety (Martinotti et al., 2018), and anecdotally, several patients have described brain fog, concentration difficulties and racing thoughts. It is possible that anxiety contributes to the development of HPPD, which could explain a potential relationship between negative drug experiences and long-term perceptual changes. Non-visual perceptual disturbances such as tinnitus, migraine with aura and vertigo are also common among people with HPPD (McConnell et al., 2025; Vis et al., 2021). The visual symptoms thus seem to be part of a broader pattern of perceptual, cognitive and affective side effects, which can strengthen the feeling of being trapped in an altered state.

Existential Distress

‘Felix’ has led an exploratory lifestyle characterized by involvement in alternative communities. He has taken ayahuasca (a brew from the Amazon in which DMT is an active substance) at retreats in South America and in local ceremonies in Norway, and became fascinated by DMT, which he has smoked several times. This has given him both therapeutic experiences and some terrible ones, such as the feeling of being possessed by demonic forces and thoughts of a cosmic curse. He frequently senses ‘energy’ in his body that doesn’t feel like his own and he is plagued by intense nightmares. During a period of high stress, these reactions contributed to borderline psychotic symptoms. Even though it never developed into a persistent psychotic disorder, the experiences still drive his ongoing preoccupation with spiritual themes and the feeling of being existentially lost. He feels a strong need to understand and resolve this inner pressure and is tempted by new psychedelic and religious ceremonies. In parallel, there have been many life stressors, such as loss of close relationships and difficult childhood experiences, which have never been fully resolved.

The triggering of persistent psychotic disorders and severe manic episodes are likely the greatest concern in regards to the normalization of psychedelics and their increased use among vulnerable patient groups. In clinical trials, individuals with high risk of psychosis or bipolar disorder are usually excluded, based on anecdotal reports and research from the 1950s and 60s (Yildirim et al., 2024; Johnson et al., 2008; Cohen, 1960). The level of risk is unclear, but some recent studies support a precautionary attitude towards high-risk groups. For example, one third of users with bipolar disorder reported increased manic symptoms, anxiety and sleep difficulties after psilocybin intake (Morton et al., 2023). Some longitudinal population studies have found increases in psychotic and manic symptoms after use, but the findings are inconsistent (Honk et al., 2024; Simonsson, Goldberg, Osika et al., 2025). Recreational use can involve co-occurring risk factors, such as particularly vulnerable individuals, polysubstance use and unfortunate circumstances.

At our clinic, we do not have experience with psychotic disorders or mania, but we do occasionally meet people with adjacent problems where psychedelics have been problematic. These include tendencies towards magical ideation, unusual sensory experiences, an unclear sense of identity, and intense preoccupation with existential or spiritual issues. The causal direction between these traits and psychedelic use is unclear (Dourron et al., 2025). Our experience suggests that these are people who were already interested in mystical phenomena and who have also had powerful experiences with psychedelics. Both the quality of the experiences and the after-effects can contribute to becoming preoccupied with making sense of distressing psychedelic experiences. Several patients have described how this search for meaning involved profound disillusionment, despair or confusion (Argyri et al., 2025; Schutt et al., 2025). The themes vary widely, but may, for example, involve feeling that one has lost oneself as a person or doubting the true nature of reality.

Increased interest in existential and spiritual topics is relatively common after psychedelic use and should not be pathologized. Several studies have found a tendency towards altered metaphysical beliefs, often in the direction of a less materialistic perspective, and this has been linked to positive impacts on mental health (Timmermann et al., 2021). For example, more than half of DMT users reported that they no longer identified as atheists after encounters with ‘entity beings’ – a characteristic effect of the substance (Davis et al., 2020). For some, however, the intensity and qualities of such experiences become difficult to relate to afterwards. The concept of ‘ontological shock’ describes a shift in philosophical or religious assumptions after especially powerful experiences and can be associated with confusion, fear or other complicated reactions. In studies of people with persistent difficulties after psychedelics, at least half report challenges with existential and spiritual themes (Robinson et al., 2025; Evans et al., 2023), and these themes are often interwoven with complaints like anxiety, compulsive rumination, perceptual changes or depression.

Extraordinary experiences often generate a need to understand what one has gone through. Among ayahuasca users, more than 1 in 10 reported experiences of being ‘attacked by energy or beings from a spiritual dimension’ (Bouso et al., 2022). Patients have described strange and overwhelming bodily sensations, such as ringing sounds and an internal restlessness that does not feel like their own. Some report thoughts of being possessed by an alien or demonic force and experience difficulty returning to everyday life because they feel overwhelmed by the phenomenon and unsure of the cause. Aixalà (2024) has described how some people become fixated on altered states of consciousness and repeatedly seek them out, even when it has negative consequences. Frequent use to cope with negative feelings has been found to predict mental health problems (St. Arnaud & Sharpe, 2023). Maladaptive coping through repeated use may relate to the observed phenomenon of ‘spiritual bypassing’, where spiritual seeking serves to avoid or circumvent difficult emotions and real-life problems (Picciotto et al., 2018).

There are several similarities between the adverse effects of meditation and of psychedelics. In meditation, there have been reports of feeling a loss of control during altered states of consciousness, intense emotional reactions, dissociation, depersonalization, perceptual phenomena and re-experiencing of traumatic memories (Goldberg et al., 2022; Lambert et al., 2021). One potentially important social difference is that psychedelic use is more often linked to individual exploration of mystical experiences, while meditation tend to involve active practice and formal meditation-based communities. This may mean that psychedelic users with distressing symptoms are more vulnerable to extreme interpretations of their experience, social isolation and maladaptive coping strategies.

Recommendations for Evidence-Based Psychological Practice

Neither our experience nor the literature suggests that difficulties after psychedelics require a separate or unique form of psychotherapy. There is limited research on the psychotherapy component in psychedelic-assisted psychotherapy (Hinkle et al., 2023; van Elk & Fried, 2022), and its primary purpose is not treatment of negative effects. While the concept of ‘psychedelic integration therapy’ focuses on the processing of difficult experiences and reactions to psychedelics, it does not constitute a unified approach. In practice, a wide range of conventional and alternative therapeutic approaches are offered under this umbrella (Glynos et al., 2024). For the most part, difficulties after psychedelics involve psychological reactions that can occur independently of the substances, and we believe psychotherapeutic approaches with broad empirical support should be prioritized. It is also worth noting that negative effects from classical psychedelics generally do not resemble addiction. Their pharmacological and subjective properties are generally not reinforcing or habit-forming (Johnson et al., 2018), and decisions on treatment strategies should not be based on the assumption that the person has a primary substance use disorder linked to psychedelics.

Meaningful application of evidence-based psychotherapy for this subgroup requires that psychological approaches be informed by the characteristic challenges encountered after psychedelic use. Thus, for clinicians to make appropriate adaptations in their practice, it is important to understand the subjective phenomena with which patients struggle. The common denominator is intense experiences with altered states of consciousness, while individual treatment needs will vary depending on how each person understands and relates to their after-effects.

Challenges for Evidence-Based Psychological Practice

Although we find that therapy sessions are often helpful for people reporting persistent difficulties, it is important to assess whether psychotherapy in itself can produce negative effects. Many of those who seek ‘psychedelic integration therapy’ are in crisis following transformative experiences with which they struggle to understand. This requires awareness about the risk of unintended effects, as the therapist may be particularly influential given the increased sensitivity of the person seeking help. For example, it may be unclear whether the person needs to process the experience more deeply or help with letting go and moving on, where excessive rumination can hinder natural recovery (Watkins & Roberts, 2020). This also applies to existential or spiritual themes: Is this something the person is distressed by because it is avoided, or has the person become too preoccupied with it? While there are no universal answers to such clinical dilemmas, an appreciation of the possibility of iatrogenic harm from therapy can facilitate understanding of how patient needs vary based on individual characteristics and circumstances.

Many hesitate to seek help with difficulties that have arisen due to psychedelic use. An obvious reason is that, in doing so, they would be admitting to illegal actions and thus wonder if this openness may have negative personal consequences. Low confidence in the clinician’s attitudes and level of knowledge can also make people reticent to disclose about psychedelic experiences. For example, some worry that the health professional will assume they have a substance use disorder because illegal substances are involved or that depersonalization and altered perception will be interpreted as signs of psychosis. In HPPD, many report not finding a specific cause of the symptoms in assessments by neurologists and ophthalmologists and have felt dismissed or disbelieved because the phenomenon is relatively unknown. Avoidance or negative encounters with health services can contribute to shame over ‘self-inflicted’ harm and to seeking out alternative sources for diagnosis and self-help (Kruger et al., 2023).

Many factors influence what each individual needs, and in a naturalistic setting, there are different pitfalls. Some have felt poorly understood in encounters with the healthcare system, where a narrow disease model can feel alienating and hinder the processing of their experiences. Others have already tried alternative therapeutic models, and have engaged deeply with new-age perspectives without improving, and find benefit from conventional psychoeducation and mainstream approaches. An interview study among users with persistent difficulties characterized by existential or spiritual themes found that helpful factors included cognitive normalization of experiences, social support and focusing on present-moment awareness (Argyri et al., 2024). Sometimes, patients describe encounters with clinicians who hold such positive views of the therapeutic properties of psychedelics that the possibility of negative effects is not acknowledged. Even in clinical trials, concerns have been raised about overenthusiastic therapists who impose their own beliefs about spirituality and philosophies on patients (Johnson, 2020). As a general principle, a cautious approach to interpreting psychedelic experiences is recommended, as well as a sober, professional stance in encounters with altered understandings of reality or existential reorientation.

A particular challenge arises in cases that resemble schizotypal functioning or psychotic states. Within the psychedelic therapy tradition, the psychiatrist and LSD therapist Stanislav Grof introduced the concept of ‘spiritual emergencies’ for states at the intersection of psychosis and religion. He argues that psychedelics can trigger disorienting crises with potential for deep personal development, where habitual assumptions about meaning and reality are dismantled. According to Grof, the phenomenon can superficially resemble psychosis, but a purely medical approach can be harmful (Grof & Grof, 1992). A strength of his model is its rich descriptions of subjective experiences and non-pathologizing language. At the same time, it is unclear how to distinguish between persistent spiritual emergencies and severe mental illness. The concept is also based on speculative ideas derived from Grof’s own practice, such as lingering psychological effects from experiences during fetal life and birth. In addition, little emphasis is placed on risks. Such interpretive frameworks are widespread in user communities and can influence how experiences are understood (Holm et al., 2023).

Bridging professional perspectives with the patient’s understanding can be difficult in practice. It is rarely helpful to determine what counts as a ‘real’ or ‘profound’ insight on behalf of the patient, and it is usually more constructive to facilitate balanced reflection through a humble and curious stance. Psychedelic experiences may also involve personally significant and emotionally charged themes in an unexpected or symbolic form. The factual validity of reinterpretations of one’s past and ‘recovered memories’ nevertheless remains uncertain (McGovern et al., 2024). From experimental research on the constructive nature of human memory, there is convincing evidence that false memories can feel as genuine as real memories. Further, false memories become more likely to occur when the person is in an impressionable state during retrieval (Schacter, 2022). Psychedelic substances are known to induce a state of high suggestibility, in which what is experienced in the present moment feels especially meaningful (Carhart-Harris & Friston, 2019). Trauma as a primary explanatory model for mental health problems is widespread in psychedelic therapy circles. The possibility of false memories should, however, encourage caution when encountering reports of memories that are reported to have re-emerged during a psychedelic experience.

An important part of the wider context is that many users turn to alternative services, including ceremonial use and underground psychedelic therapy. There have been reports of cases of sexual assault, violence and self-harm at psychedelic retreats (Grierson & Siddique, 2016; Kruger et al., 2025). A more common issue is emotional destabilization and difficulties resuming normal life (Bouso et al., 2022; Lutkajtis & Evans, 2023). Typical ayahuasca stays in South America last one to two weeks and include three to six ceremonies, conducted in groups with participants from different countries and led by local ‘shamans’. It is unclear whether the intensive dosing increases risk, and competence among the guides in handling negative reactions varies. Similarly, underground therapy by definition lacks formal evaluation of safety and standards of care, and serious cases of harmful practice have been uncovered (Ross & Nickles, 2021–2022). This does not mean that retreats or underground therapy are generally harmful, but it highlights recurring issues: Who is at high risk, what is an acceptable level of risk and what can be learned from particularly severe cases?