Depersonalization-derealization disorder (DPD) is defined by persistent or recurrent experiences of detachment from the self or the surroundings, as well as emotional numbness and distorted, anomalous subjective experiences1. Clinical descriptions emphasize the need to distinguish DPD from psychosis, primary mood disorders, panic-related dissociation, substance-related states, and neurologic conditions2. A recent systematic review estimated that DPD affects approximately 1%–2% of the general population, with symptoms commonly emerging in adolescence or early adulthood3. Although some individuals describe symptoms as subtle or episodic at onset, chronic symptoms can impair academic, occupational, and social functioning4.
Treatment evidence remains limited. A systematic review examined clinical evidence for various treatment methods along with their efficacy and deficiencies, highlighting gaps in studies compared to the high prevalence of DPD5. Studies of psychotherapy, pharmacotherapy, and neuromodulation for DPD were heterogeneous and often small, with few controlled trials and no universally accepted medication protocol5. Recent reviews have also continued to frame DPD as a disorder with neurobiological correlates rather than a purely nonspecific complaint, including trauma-related neural models and preliminary immune-system findings6,7. However, these data do not establish a standard intervention pathway.
Several treatments are relevant to the present case. Neuromodulation approaches have included repetitive transcranial magnetic stimulation of the temporoparietal junction, a region implicated in self-location and bodily self-processing, but the evidence is still based on small samples8. Transcranial direct current stimulation (tDCS) has broader mechanistic and clinical relevance in psychiatric research, yet its role in DPD remains exploratory9. Evidence regarding lamotrigine treatment for DPD remains limited. A retrospective series suggested that lamotrigine might be beneficial when used as an adjunct to antidepressant treatment, whereas a placebo-controlled crossover trial did not demonstrate efficacy for lamotrigine monotherapy10,11. Duloxetine, a serotonin-norepinephrine reuptake inhibitor (SNRI), has shown potential benefit in an exploratory study of patients with DPD, with a trend toward earlier improvement in emotional numbness; however, evidence supporting its efficacy remains preliminary12. Case reports remain useful for generating testable hypotheses when interpreted cautiously13.
Evidence for the treatment of DPD remains limited, leaving uncertainty regarding treatment selection and sequencing in clinical practice5. This case report describes an individualized, stepwise treatment course involving an initial trial of tDCS, subsequent pharmacotherapy with duloxetine and adjunctive tandospirone, and later lamotrigine augmentation. In this report, the use of neuromodulation and pharmacotherapy at different stages of care is reported as a multimodal treatment regime. The contribution of this case lies in documenting the rationale for sequential treatment adjustments alongside longitudinal symptom and cognitive assessments. The aim is to generate hypotheses concerning individualized multimodal care for DPD.
Case presentation:
The patient was an 18-year-old male who first presented to the outpatient clinic in November 2020 with persistent derealization. Intermittent episodes had begun in January 2013, during the sixth grade of elementary school, and initially did not interfere with daily life. In 2017, during high school, the symptoms worsened and became persistent, remaining present until the initial consultation.
At the first visit, the patient described the surrounding world as unreal and reported a robot-like experience, comparable to being a controlled character in a virtual-reality environment. The patient also reported emotional blunting, limited emotional fluctuation, poor memory, slowed reactions, and impaired concentration, with associated difficulties in academic and social functioning.
As for mental status examination, the patient showed clear consciousness, intact orientation, cooperative contact, and preserved insight. Reality testing was intact. The patient denied persistent low mood, elevated mood, and psychotic symptoms. Physical examination showed no obvious abnormal signs. Electroencephalogram (EEG), electrocardiogram (ECG), and magnetic resonance imaging (MRI) findings were all within normal limits.
In terms of personal background, the patient was generally healthy, denied a drug or food allergy history, and had no family history of mental illness or inherited physical disease. The patient denied psychoactive substance use, illicit drug use, or head trauma before or after onset.
Diagnosis, assessment, and plan:
The diagnosis of DPD was established independently by two psychiatrists through clinical interviews based on DSM-5 criteria. Physical illnesses and other psychiatric disorders that could account for the symptoms were excluded. The diagnosis was supported by persistent derealization and emotional detachment, preserved reality testing, intact orientation, preserved insight, and clinically meaningful academic and social impairment.
Differential diagnosis was considered clinically. Psychotic disorder was less likely because the patient retained reality testing and did not show delusions, hallucinations, or disorganized thought. Major depressive disorder with dissociative symptoms was less likely because the dominant complaint was chronic derealization rather than a sustained depressive syndrome, and the patient denied persistent depressed or elevated mood. Anxiety-related dissociation was less likely because symptoms were persistent rather than limited to panic attacks or acute anxiety episodes. Substance-or medication-induced symptoms were less likely because symptoms began years before treatment, and the patient denied psychoactive substance and illicit drug use. Post-traumatic stress disorder was considered less likely because the patient denied a history of psychological trauma. Other dissociative disorders, particularly dissociative identity disorder, were considered less likely because the patient denied identity-state switching and autobiographical memory gaps beyond ordinary forgetting. Borderline personality disorder was considered less likely given the reported good interpersonal relationships and absence of emotional instability.
Temporal lobe epilepsy was also considered in the differential diagnosis. The patient reported no history of physical illness, including known epilepsy. The persistent nature of the symptoms over several years was less suggestive of an ictal phenomenon. Neurological examination revealed no obvious abnormalities, and EEG and brain MRI findings were within normal limits. However, a normal EEG does not exclude epilepsy.
Baseline symptom and cognitive assessment included the Cambridge Depersonalization Scale (CDS), Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS), Hamilton Depression Rating Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), and MATRICS Consensus Cognitive Battery (MCCB). The CDS was used to quantify depersonalization and derealization symptoms14. At baseline, scores were CDS 147, SDS 46, SAS 37, HAMD 8, HAMA 5, and MCCB composite T-score 49.
An individualized multimodal treatment approach was implemented sequentially, with intervention selection and subsequent adjustments guided by patient preferences, persistent symptoms, clinical response, and tolerability. The patient initially preferred not to take medication and declined psychotherapy because of concerns about the overall treatment duration and the time required for individual sessions, expressing a preference for an approach expected by the patient to provide more rapid relief. tDCS was therefore selected as an initial nonpharmacological trial, considering the patient’s preference and its generally favorable tolerability reported in other populations. After a transient improvement that did not persist, duloxetine 60 mg/day and tandospirone 10 mg three times daily were started. Duloxetine was selected to target persistent DPD symptoms, including emotional numbness, based on the treating team’s prior clinical experience of favorable responses in patients with DPD and its potential relevance to serotonergic and noradrenergic mechanisms. Tandospirone was used as an adjunct for residual anxiety and somatic tension. Duloxetine was later optimized to 120 mg/day. Lamotrigine was then added and titrated because derealization persisted despite improvement in emotional symptoms and concentration. The patient was monitored through outpatient and online contacts, repeated scale assessments, and adverse-effect review.