There has been considerable debate regarding the causal relationship between chronic cannabis abuse and psychiatric disorders. Clinicians agree that cannabis use can cause acute adverse mental effects that mimic psychiatric disorders, such as schizophrenia and bipolar disorder. Although there is good evidence to support this, the connections are complex and not fully understood.As the research in the endocannabinoid system is emerging, the neurobiological effects of cannabis are being evaluated in the development of psychiatric illness for those individuals who may be genetically vulnerable. Here we present a case of a college student who initially suffered from an acute psychotic breakdown secondary to cannabis abuse that manifested into bipolar disorder with psychosis.