Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician
Psychosis is characterised by a loss of connectedness with reality. A person may develop false ideas or beliefs about reality (delusions) which in themselves may be based on false perceptions (hallucinations).
People experiencing psychosis also have characteristic flaws in the ways they think. These are termed 'thought disorders'. Examples are tangential thinking, loose associations between ideas, and incoherence.
Psychosis significantly impairs work, family and social functioning. People with psychoses often experience poorer physical health. The worse the psychotic symptoms are, the higher the associated level of impairment(251).
Psychotic symptoms can occur in response to physical conditions, e.g. acute delirium with septicaemia. Alternatively, psychoses can be functional. There are two broad classes of functional psychotic disorders: schizophrenia and bipolar disorder.
Generally, schizophrenia is a chronic condition with exacerbations, but always with some background symptoms. Bipolar disorder is generally an intermittent condition with the expectation of full recovery between episodes. There is considerable overlap between the two conditions and fluidity of diagnosis.
Symptoms of schizophrenia are sometimes grouped into two categories:
- Positive symptoms such as hallucinations and delusions.
- Negative symptoms such as social withdrawal and lack of energy and motivation that are similar to those found in depression.
Shortening the period of untreated psychosis (whether this be substance induced or the early stages of psychotic disorders) has the potential to have a positive impact on treatment outcomes.
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7.1.1 Management approaches to psychosis
- Antipsychotics have shown their effectiveness in treating psychosis. The newer, so called atypical agents are effective at managing symptoms of psychosis****(252, 253), produce fewer extrapyramidal side effects****(252), are possibly associated with fewer relapses****(253), show possible improvements in cognitive deficits***(254-256) and have improved tolerability compared to typical antipsychotics(1, 2).
- Adjunctive benzodiazepines may be required for breakthrough anxiety and agitation and should be restricted to short-term use and gradual dose reduction(2).
- Antidepressants may also be useful for the treatment of associated depression(15).
- Bipolar disorders are best managed with mood stabilising drugs such as lithium****(257-259), sodium valproate****(259), carbamazepine****(259, 260) and lamotrigine for depression****(257, 258, 261) with atypical antipsychotics such as olanzapine and risperidone being used in manic phases****(259, 262).
- Mood stabilisers such as sodium valproate, carbamazepine and lamotrigine are hepatically metabolised and liver function is particularly pertinent when prescribing these classes of medication.
- People with bipolar disorder and comorbid substance use are at a greater risk of contracting blood borne viruses due to increased risk taking, and are more likely to consume large quantities of alcohol. Therefore, liver function should be assessed in patients with bipolar and comorbid substance use disorders.