Smiley Australia

Information on Physical Illnesses or Organic Causes that can be misdiagnosed as Psychosis or Mental Illness:

There are a number of physical illnesses the symptoms of which can be (and have been) mistaken for mental illness. Various heart and thyroid problems, epilepsy, asthma and even menopause are among many medical conditions that can mimic anxiety or depressive disorders by causing symptoms such as chest pain, breathlessness, rapid heart beat, dizziness, nausea and sweating.

Especially in situations where the patient does not 'fit the criteria' for mental illness, or there are 'unusual' aspects to their case that are difficult to explain, thorough medical investigation is warranted to exclude physical causes as a priority.

The 'criteria' for diagnosing mental illness is not an exact science. The methods and empirical data for diagnosing physical illness are far more extensive and it is logical that every physical cause should be precluded before any 'mental' diagnosis is considered.

This list is not exhaustive but provides some information for alternative diagnosis under the guidance of your health care provider:


The thyroid gland is responsible for producing two hormones that help regulate our metabolism. These hormones are referred to as T3 and T4. They also have a direct effect on most of our organs including the heart.

Hyperthyroidism is overactivity of the thyroid gland. There are a number of causes of hyperthyroidism. Excessive release of thyroid hormones may be intermittent causing signs and symptoms to come and go.

Symptoms of hyperthyroidism are the same - regardless of the cause. Many of the symptoms may be misinterpreted as mental illness, particularly depressive disorders and hypomania. A quick look at the symptoms will show you why!

Symptoms and Signs of Hyperthyroidism include:

  • Anxiety
  • Nervousness
  • Hyperactivity
  • Emotional lability
  • Fatigue
  • Insomnia
  • Trembling hands
  • Weight Loss
  • Muscle Wasting
  • Proximal muscle weakness
  • Tachycardia - Fast heart beat
  • Palpitations - Irregular heart beat
  • Breathlessness
  • Warm and moist skin
  • Hair Loss
  • Increased bowel movements
  • Heat insensitivity
  • Sweating
  • Staring gaze
  • Eyelid retraction and lag
  • Light or absent menstruation

For patients who have established epilepsy, thyrotoxic episodes may cause an exacerbation of seizure activity.

Diagnosis can be confirmed by blood test showing low levels of thyroid stimulating hormone (TSH) and high levels of T3 or T4 or both.


Hypoglycaemia is a condition where levels of blood sugar in the body fall below the minimal level required to provide the brain with fuel (glucose), resulting in an impairment of brain function. It is the opposite of diabetes which is an excess of blood sugar (Hyperglycaemia).

Symptoms and effects of hypoglycaemia vary between individuals from a vague 'feeling bad' to coma and rarely permanent brain damage or death.

Moderately severe hypoglycaemia in adults and older children may resemble mania, mental illness or intoxication with drugs or alcohol.

There are a number of causes of hypoglycaemia and it can affect any person at any age.

One of the most common causes of hypoglycaemia occurs as a complication of treatment for diabetes with insulin or oral medications. Receiving too much insulin to lower excess blood sugar can cause the opposite problem of not enough blood sugar .

Severe disease in any of the major organ systems in most cases can cause hypoglycaemia as a secondary symptom.

Hospitalised patients who are unable to eat can suffer with hypoglycaemia or it may be iatrogenic (caused by medications).

Prolonged fasting and a number of other disorders and medications may cause hypoglycaemia.

The body reacts to low blood sugar by compensating with alternative energy sources and release of the hormones epinephrine/adrenaline and glucagon to achieve this.

The release of these compensatory hormones creates bodily symptoms or reactions as a direct result of the type of hormone released.


Not all of the following manifestations occur in every case and there is no consistent order to the appearance of symptoms, however an individual is likely to exhibit the same symptoms from episode to episode.

Symptoms and signs of hypoglycaemia fall into three categories:

Neuroglycopenic (From the reduction of fuel in the brain - Neuroglycopenia);
Adrenergic (Those triggered by the release of the hormone Adrenaline);
Glucagon Manifestations (Those triggered by the release of the hormone Glucagon).

Neuroglycopenic Signs & Symptoms:

  • Personality change
  • Emotional lability
  • Negativity
  • Impaired judgement
  • Irritability, belligerance
  • Combativeness, rage
  • Low mood (dysphoria), depression, crying, moodiness
  • Abnormal thinking or inability to process thoughts rationally.
  • Fatigue, lethargy, apathy, weakness, dizziness, sleep
  • Incoordination, movements could be mistaken for 'drunkeness'.
  • Staring, daydreaming, blurred or double vision, 'glassy' look.
  • Confusion or delerium
  • Amnesia
  • Slurred speech or difficulty speaking.
  • Abnormal breathing
  • Specific or general motor deficit, paralysis.
  • Headache
  • Parathesias (Tingling in fingers, toes, feet, hands or limbs).
  • Stupor or coma
  • Seizures
  • Automatic behaviour (automatism)

Adrenergic Signs & Symptoms:

  • Dilated pupils
  • Shakiness or tremor
  • Nervousness
  • Anxiety
  • Heart palpitations (Irregular heart beat)
  • Tachycardia (Fast heart beat)
  • Sweating or feeling warm.
  • Numbness or pins and needles in the fingers.

Glycopenic Signs & Symptoms:

  • Nausea and/or vomiting
  • Abdominal discomfort
  • Hunger
  • Gastrointestinal or stomach noises (Borborygmus).

Diagnosis and Treatment:

Blood tests can reveal the presence of hypoglycaemia - either as low blood sugar levels or by the presence of hormones and metabolites in irregular quantities.

Portable 'fingerstick' glucose meters used by diabetics in the home situation can be unreliable at low reading levels. In addition, blood sugar levels in the capillaries (small veins in the extremities) are generally 10-15% lower than in the arteries or veins. Portable measuring devices may show a lower reading in hypoglycaemia than actual.

Treatment to reverse hypoglycaemia is by provision of carbohydrates or starch which is rapidly digested to glucose. Where the patient is unconscious or combative, treatment may be delivered with intravenous infusion of glucose or injection of glucagon. Reversal can be achieved in a matter of minutes.

Specific treatment will depend on the cause of hypoglycaemia and if the patient is diabetic care should be taken so as not to produce hyperglycaemia afterwards.


Certain seizure types cause symptoms which have been misdiagnosed as various psychotic mental illnessess. Please read our Epilepsy pages for detailed information of the different forms of epilepsy.

Prescription Medication Psychosis:

There are individuals who react quite differently to medications that others take with little or no problems.

Antidepressants, benzodiazapenes, (and some other non-psychiatric medicines) can induce psychosis and mania in some people.

This unfortunate reaction may be misinterpreted as a worsening of depression, the emergence of bipolar disorder, schizoaffective disorder, or schizophrenia or other mental illness.

If you or someone you care for has recently started a course of antidepressant, sedative or other medication please be aware of the following signs of psychosis, especially where the person has never exhibited these types of behaviour previously:

  • Verbal aggression
  • Physical aggression
  • Argumentative
  • Reduced need for sleep - staying up all night or most of the night for days on end
  • Delusions - believing things that are not true
  • Hallucinations - seeing things that are not there
  • Heightened sense of self importance
  • Talking very fast or talking constantly with a rapid change of topics.
  • Taking unnecessary risks of any type

Consider the possibility that the psychosis may be medication induced. These effects may show immediatly upon commencement of medication or anytime up to a month or two later (maybe longer depending on the individual).

Do not hesitate to contact your GP to get help. Psychosis is a serious disorder of thinking and the person is not in control or aware of their actions.

Psychosis can cause the individual to take extreme risks with their health and safety and be unaware of the impact of their actions on the health and safety of others.

If a person is experiencing an extreme reaction to medication this reaction will not go away until the cause is removed, i.e. the medication is ceased.

Do not suddenly stop taking medication without consulting your doctor. It is very dangerous to suddenly cease these medications and may lead to further complications and severe physical withdrawal symptoms.

The type or possible symptoms experienced in drug induced psychosis are the same as those experienced by persons with psychotic mental disorders.

For more information on psychosis please go to our 'Bipolar' Information pages.

For more information on specific side effects please see our 'medication' page and click on the 'side effects' and associated links.

Marijuana Psychosis:

Marijuana psychosis appears to have become an expedient explanation for many people suffering psychosis, especially those who don't 'fit' the normal diagnostic criteria for mental illness or who have later life onset of symptoms. This has led to some patients not receiving satisfactory or further investigative diagnosis of their conditions - to their detriment.

In the late nineties, scientists discovered some surprising facts:

  • That every human being has a 'natural' cannabis system in the brain. (These 'cannabinoid' receptors are a necessary part of our major signalling processes)
  • and;

  • Marijuana doesnít act like other drugs. The active ingredient in marijuana - THC, taps into the natural system of these receptors.

Unlike our natural internal cannabis which breaks down quickly, THC locks onto a cannabinoid receptor and holds open the floodgates on the potent neurotransmitter 'dopamine'. The longer acting THC floods the midbrain with dopamine and too much dopamine in this area can cause psychosis in susceptible individuals. An excess of dopamine in this region of the brain is known as 'the wind of psychotic fire'.

Antipsychotic medications target the same region of the brain to block dopamine and reduce psychotic symptoms.

We now have a definitive answer on the cause of Marijuana psychosis, thanks to a long term study in New Zealand undertaken by Professor Richie Poulton - Director of the Dunedin Multidisciplinary Health and Development Research Unit.

This longitudinal study of 1000 people has been underway since 1972. In 2005 they made an exciting discovery - a gene for vulnerability to psychosis called the Catechol-O-methyltransferase (COMT) gene, it regulates the neurotransmitter - dopamine. The COMT gene stands out in families with schizophrenia.

We all have two COMT genes. In the majority of people both genes are good or they have one good and one bad gene. In a small number of people it has been discovered that both these genes are defective, and this impairs the individuals ability to regulate dopamine.

It is estimated that the number of people with these defective genes is less than 1% of the population, however it is also now known that only a small number of these will develop psychosis through using marijuana during adolescence.

The Dunedin study revealed that adolescents who had the bad version of the gene, and who use cannabis on a monthly basis or more, had an 11 fold increase in their chances of developing psychosis by their mid 20ís. The use of cannabis among this group of people has a large impact on the likelihood of developing psychosis.

The study found the risk was constrained to the period of adolescence. Adults were not affected in this way.

The Dunedin findings are supported by the fact that nearly one third of the population has used marijuana a some time in their lives. We (thankfully) don't have one third of the population running around with marijuana psychosis.

At present a test is not available to the public to determine those at risk - however it will only be a matter of time before such a test is available which will take much of the guesswork out of diagnosis.

There is no doubt that people with these defective genes are highly susceptible to psychosis if they are users of marijuana - especially during adolescence when the brain is still developing.

While the brain continues to develop over the course of a lifetime, there is a distinct period of remarkable change that occurs during adolescence. It is a period of peak sensitivity in the brains development including changes in the brains architecture and synapse connections.

It is very important for teenagers and young people to realise the risks they run by using illicit drugs and alcohol during these formative years. This can not be emphasised strongly enough.

Likewise, people who are susceptible to developing schizophrenia should refrain from indulging in mind altering substances as these can be a catalyst for the development of the disease.

Psychosis caused by marijuana will thankfully remit when the individual ceases use of the drug. Antipsychotics may be required (depending on the severity of the psychosis) to alleviate symptoms until a full remission (usually about 3 months) occurs. Needless to say, if you have suffered psychosis through using illicit drugs you would be extremely foolish to take up the habit again.

Psychotic episodes can damage the brain. Continuing psychotic episodes do cause compounding damage and physically change the structure of the brain - this is a fact. A level of responsibility on the part of the patient is always required to achieve lasting recovery. As a patient you do have a responsibility for your own continued wellbeing.

If you have suffered marijuana induced psychosis but escaped any long term damage and feel tempted to get involved with drugs again just imagine being on antipsychotic medication for the rest of your life and how that will make you feel. The first time you can say you were just unlucky, but you would have to be pretty stupid to risk your mental health again.

You may wish to consider this: There are thousands of people who have to take antipsychotic medication every day just to function and they would give anything to be well again. These people were born with their condition, or they have suffered head trauma or brain damage through accident or illness. None of them had the luxury of your choice.

Don't trash your future if you're lucky enough to have the option.

For those diagnosed with marijuana psychosis who do responsibly cease their drug use yet fail to respond to treatment, further investigation of the nature of their illness is warranted in light of the Dunedin findings.

This new evidence indicates the potential that in some cases the original diagnosis may have been in error. The percentage genetically prone to suffer psychosis from marijuana is likely far fewer than the numbers being diagnosed. A systematic review of these cases would be welcomed.

Illicit Drug Psychosis:

Psychosis caused by use of various illicit or street drugs has the same symptoms as psychosis from other causes.

Certain drugs cause psychosis while under the influence, other drugs can cause psychosis from cronic usage.

Type and length of use of street drugs will determine whether psychosis is temporary or as a result of damage to the brain from long term use.

Alcoholic Psychosis:

Cronic use of alcohol can cause psychosis. Psychosis may be temporary (i.e from 'binge' drinking), or permanent if the individual has a long history of alcohol abuse.

Lead Poisoning:

Lead poisoning (usually by ingestion) may initially show few symptoms.

Cronic lead poisoning (over time) may present in adults as personality change, cognitive deficits, peripheral neuropathy (damage to the nerves in the extremities (fingers, toes etc), anemia, and progressive renal dysfunction. These symptoms may be irreversible.

Cronic lead poisoning in children may cause mental retardation, seizure disorders, aggressive behaviour disorders, developmental regression, cronic abdominal pain and anemia.

Mercury Poisoning:

Exposure to mercury can cause severe neurological and kidney damage. Use of mercury is now banned but in the 1800's, it was used in making mirrors among other things. Hat makers were also exposed to mercury in their trade and this is where the term "as mad as a hatter" came from, they went mad with exposure to mercury.

Mercury poisoning has resulted from ingestion of tissue boxes and cigarette packets.

Mercury is found in antique clocks, lamps, mirrors and was still used relatively recently in the making of thermometers, barometers, and blood pressure equipment.

Mercury is also found in fish, especially larger species such as sharks, tuna, king mackerel etc. Consumption of these should be limited.

Mercury is an environmental hazard. Liquid mercury can vapourise and be breathed in causing toxic pneuomonia.

Level of exposure is directly related to severity of symptoms. Signs of mercury poisoning include inflamation of the gums, tremors, and a number of psychiatric symptoms including:

Memory Loss, fatigue, weakness, excitability, irritability and depression.

Blood tests are used to detect mercury.

Vitamin B12 Deficiency:

Cronic deficiency in Vitamin B12 may result in megaloblastic madness (paranoia). Other symptoms include mild depression, confusion and delerium.

Blood tests can confirm Vitamin B12 deficiency.

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