Authors’ response to the commentary, “Cannabis and psychopathology: A 2024 snapshot − Examining the complexities of diagnostic stability in cannabis-induced psychosis”

Sir,

This is in response to the commentary on our recent review article titled “Cannabis and Psychopathology: A 2024 Snapshot − Examining the Complexities of Diagnostic Stability in Cannabis-Induced Psychosis.” Here, the authors have raised concern on three issues (i) cannabis withdrawal psychosis within the spectrum of cannabis induced psychosis (CIP); (ii) prognosis of CIP, and (iii) diagnostic stability of the same. CIP can be viewed as a spectrum, including intoxication, withdrawal, and those spanning beyond that, but the ICD-11 explicitly excludes the intoxication and withdrawal psychosis to diagnose induced psychosis. We followed the accepted nosological classification in our article to keep our discussion focused.[1]

Cannabis intoxication psychosis has been studied for more than a century. The hemp psychosis and the early anecdotes apparently portray the same, which is an acute onset, transient, and remits completely within hours.[2,3] The neurobiology and conceptual understanding became much clearer in the initial two decades of the 21^st century, due to δ9THC administration studies in human subjects.[4] Although cannabis intoxication psychosis is a relevant topic, there have been few clinically relevant conceptual changes in this topic in the last decade. The interested readers can go through the previous articles of this series for a more nuanced idea about the intoxication psychosis.[5,6,7]

It is interesting to note that the authors brought up the issue of cannabis withdrawal psychosis. To date, this is a sparsely studied entity, which may have significant neurobiological overlap with the CIP. The published data also show that the majority (around 72%) of the withdrawal psychosis converts to independent psychosis later on.[8] This further underlines the unstable and vague nature of this concept.

The authors pointed toward our pessimism about the prognosis of CIP, and stressed the good prognosis of the same. Any substance-induced psychosis should have complete remission after cessation of the offending substance, which also holds true for cannabis. We wanted to highlight the poor prognosis of CIP in vulnerable groups, and those with continued, heavy, especially high-potency cannabis use.[9] This has been documented across the studies, and we think this caveat is essential in the current era of liberalization of cannabis use.

The authors raised concerns about keeping CIP as a provisional diagnosis. The CIP patients come to clinical attention in their acute phase, and to confirm the diagnosis of CIP, we should withhold psychotropics for at least a month after complete cessation of cannabis,[1,10] which is not practical. As these patients receive antipsychotics much earlier, it is impossible to ascertain whether the response is due to antipsychotics or to cannabis cessation. So, CIP diagnosis remains provisional in nearly all cases. Although the clinical experience may show a favorable prognosis for CIP, we must be mindful of the high treatment disengagement rates in dual diagnosis patients. Those studies with a longitudinal follow-up ascertain that CIP has a high conversion rate to independent psychosis, ranging from around 20% to 40%.[11,12] We wanted to highlight that in our article and show that CIP and independent psychiatric disorders lie on a spectrum.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.