Comorbid cannabis use and panic disorder: short term and long term follow-up study.

OBJECTIVES: The aim of the study was to compare the treatment of panic disorder in patients with or without cannabis use according to response, relapse and side effects.

MATERIALS AND METHODS: 66 panic disorder (PD) patients were included in our study. All the subjects met the DSM-IV diagnosis of panic disorder (n=45) or panic disorder with agoraphobia (n=21). Twenty four patients experienced their first panic attack within 48 h of cannabis use and then went on to develop PD. All the patients received pharmacologic treatment with paroxetine (gradually increased up to 40 mg/d). A masked rater that was blind to the group allocation, assessed patients in order to rate anxiety symptoms and medication side effects. Relapse was defined as the occurrence of a single panic attack after remission of panic symptoms. The instruments were administered at baseline and also at the 4, 8 and 12 weeks visits and at the 1 year visit.

RESULTS: The two groups responded equally well to paroxetine treatment as measured at the 8 weeks and 12 months follow-up visits. There were no significant effects of age, sex and duration of illness as covariates with response rates between the two groups. Also PD or PDA diagnosis did not affect the treatment response in either group. There were no significant differences in weight gain, sexual side effects or relapse rates between patients according to gender or comorbid diagnosis.

SUMMARY: Acute cannabis use can be associated with the onset of panic attacks and panic disorder, and panic disorder which develops after cannabis use is responsive to pharmacotherapy.