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Misdiagnosis of schizophrenia with ADHD and cannabis use

Franjo Grotenhermen

It is largely undisputed in science that cannabis use can accelerate the onset of schizophrenic psychosis. It is probable that cannabis can increase the risk for the onset of psychosis. Conclusive certainty is hard to come by here. But caution is indicated, so this possibility must be taken seriously, especially in connection with adolescent cannabis use. That is one side.

Here is the other side from my medical practice. I have treated patients who have been misdiagnosed as having schizophrenia in connection with cannabis use. Such misdiagnoses can be devastating for those affected. The cases I have seen in my practice could have been avoided by a non-judgemental approach and careful history taking. It would have been necessary to accept that cannabis can also be helpful in some psychiatric disorders that are associated with impulsive outbursts. Not necessarily, but it can.

In an article in the Süddeutsche Zeitung of 19 May 2010 entitled "Der verirrte Blick in die Seele" (The lost view into the soul) it says: "Hardly any other subject is as prone to misdiagnoses as psychiatry - doctors and psychologists need more critical self-control. Margret O. knew that she was mentally ill. After all, she is a psychiatrist herself. The doctor had already treated dozens of manic patients. But when she herself went to a clinic during a manic episode, her view of her own profession changed drastically. "It was a key experience how the doctors reacted when I refused to take a medicine," she recalls. If she did not take the drug voluntarily, nurses would strap her to a bed and force the pills down. "Until this threat, I had myself reasonably under control, but that's when I flew into a rage," Margret O. Violence is still one of the pressures used in psychiatry today. Patients with depression, panic attacks or schizophrenia do not always come to a clinic voluntarily; many are admitted under pressure from their families or from the police."

Recently, a patient presented to me who had been diagnosed with "paranoid schizophrenia" in hospital. He told me that he had already been diagnosed with ADHD, i.e. a disorder of concentration, activity and impulsivity, in childhood. This diagnosis had been confirmed in adulthood. He had been in inpatient treatment again for a few weeks in spring. The doctor's report described typical symptoms of ADHD, including repeated violent outbursts due to an impulse control disorder, which led to complaints by neighbours with subsequent police intervention. This resulted in repeated forced admissions to the psychiatric ward, each time confirming a "known paranoid schizophrenia". Against his resistance, he was then treated with neuroleptics.

The article from the Süddeutsche Zeitung says: "Most patients comply with the doctors' advice and are discharged after days or weeks in a stable condition. Those who do not comply easily get into a vicious circle: neurologists are often so convinced of the correctness of their diagnosis that they see a patient's resistance as proof of his mental illness."

Everything that was written in the medical discharge report from the clinic as signs of paranoia or paranoid schizophrenia was quite comprehensible. The medical report from the clinic provides more information about the prejudices of the psychiatrists working there than about the patient. The patient was friendly. His thought processes were orderly and structured. He gave information freely and everything he reported was comprehensible, including the threats that had been classified as paranoid. He reported that whenever he has enough cannabis, he does not have impulsive outbursts. He only has these when he does not have enough cannabis. I have heard this from ADHD patients more than 200 times in the past years. He further stated that he does not benefit from neuroleptics, so he always stops taking them immediately after hospitalisation.

Now begins what I have not done the first time. The person will see a psychiatrist who knows that cannabis can help with ADHD, because of course I can't make a psychiatric diagnosis myself. That has to be done by a psychiatrist. Then he will probably start a normal ADHD therapy with cannabis, because he does not tolerate methylphenidate well.

The article in the Süddeutsche Zeitung goes on to say about misdiagnoses in psychiatry: "The problem is that doctors are usually right. But not always. Sometimes a patient has every reason to defend himself because the diagnosis is wrong. "Misdiagnoses are a common phenomenon in psychiatry," says psychologist Hans-Ulrich Wittchen from the TU Dresden. "They are probably significantly more frequent than in other subjects." While surgeons, internists and general practitioners have recently established error reporting systems, such initiatives are lacking in psychiatry. (...) Cautious psychiatrists therefore only make their first diagnosis provisionally. Only the intensive care of the patient creates the basis for confirming, modifying - or dropping the first suspicion."

I know many good and dedicated psychiatrists. However, cannabis apparently triggers psychological stress reactions in many psychiatrists, which they have not yet been able to deal with adequately. This falls back on psychiatry.