Cannabis-Associated Delusions in Young Adult with Severe Emetophobia

Case at a Glance

A 19-year-old transgender male presents with escalating emetophobia and episodic delusions that began approximately one year after initiating recreational cannabis use. The patient experiences monthly delusional episodes involving fears of vomiting-related contamination and persecution, along with false memories of exposure events.

Patient's Story

The patient is a 19-year-old assigned-female-at-birth transgender male (height 5'2", weight 60kg) currently on testosterone therapy. He has a longstanding history of emetophobia (fear of vomiting) that was previously manageable but has significantly worsened over the past year. He began using cannabis recreationally 1-2 times per week approximately 12 months ago. The patient reports no family history of psychotic disorders and takes no prescription medications aside from hormone therapy.

Initial Assessment

The patient presents with two distinct but related symptom clusters: 1) Severe contamination-type obsessive-compulsive behaviors centered around vomiting phobia, and 2) Monthly delusional episodes lasting several days where he becomes convinced that leaving his house will result in witnessing vomiting or contracting stomach illness, and that family members will deliberately expose him to vomit. He also experiences brief episodes of false memories, believing he was exposed to vomit when he never left his house.

The Diagnostic Journey

The patient and his therapist had been considering an OCD diagnosis due to escalating obsessive behaviors and contamination fears. However, the presence of fixed false beliefs (delusions) and false memories raised concerns for a psychotic spectrum disorder. The temporal relationship between symptom onset and cannabis initiation prompted consideration of substance-induced psychotic disorder. No family history of psychosis was reported, though cannabis can trigger psychotic symptoms even without genetic predisposition.

Final Diagnosis

Provisional diagnosis of Cannabis-Induced Psychotic Disorder with prominent delusions, superimposed on pre-existing Specific Phobia (Emetophobia) with evolving Obsessive-Compulsive Disorder features.

Treatment Plan

Immediate discontinuation of cannabis use was recommended as the primary intervention. Plan for psychiatric evaluation to assess need for antipsychotic medication if symptoms persist after cannabis cessation. Continued psychotherapy focusing on exposure and response prevention for OCD symptoms and cognitive-behavioral therapy for emetophobia. Regular monitoring for symptom resolution following substance discontinuation.

Outcome and Follow-up

Patient agreed to immediate cannabis cessation and expressed optimism about symptom improvement. Follow-up appointments scheduled to monitor symptom resolution and assess need for additional psychiatric interventions. Patient education provided regarding the relationship between cannabis use and psychotic symptoms, particularly in vulnerable individuals.