Global prevalence of trichotillomania: a systematic review and meta-analysis and depression subtypes and their response to counselling for depression

Lay Summary

Trichotillomania prevalence: Trichotillomania is a condition characterised by five core symptoms, a) recurrent hair pulling, resulting in hair loss, b) unsuccessful attempts to stop or reduce hair pulling, c) significant distress or impairment in social and occupational functioning because of hair pulling d) the hair pulling, or loss cannot be attributed to another medical condition or e) be attributable to another mental disorder. Trichotillomania is classified under Obsessive-Compulsive and Related Disorders in the Diagnostic and Statistical Manual 5 and the International Classification of Diseases 11th Revision after previously been classified an impulse control disorder. Uncertainties in trichotillomania’s prevalence remain, with existing study estimates varying considerably. These uncertainties can make inferences about the level of resource needed for assessment and treatment difficult. Therefore, the current systematic review and meta-analysis aimed to summarise and reliably estimate the point and lifetime prevalence of trichotillomania. A systematic literature search was conducted before studies were narratively synthesised and a meta-analysis conducted. Additional variables such as age, gender and sample size were explored to ascertain their impact on prevalence rates. The pooled estimated point prevalence for trichotillomania was 3% with a pooled estimated lifetime prevalence of 2%. Larger studies reported lower point prevalence rates with diagnostic interviews being associated with higher lifetime prevalence rates compared to studies using self-report assessments. The current study provides an up-to-date global prevalence rate for lifetime and point prevalence of trichotillomania and provides guidance on the methods of future studies and clinical implications for practice, classification, and service development.

Depression subtypes and their response to counselling: Depression is one of the world’s leading public health concerns with approximately 264 million individuals suffering worldwide. Despite this, existing psychological interventions are only moderately effective in its treatment. This includes counselling for depression (CfD) that is used in the Improving Access to Psychological Therapies (IAPT) initiative. Evidence has suggested that depression consists of several subtypes that respond differentially to treatment. The current study uses similar methodology to previous research to build on the evidence base by examining depression subtypes and their response to CfD. Data collected across eight National Health Service (NHS) trusts containing clinical records of 5646 was used. Analysis identified depression subtypes and their response to counselling based on a questionnaire to assess depression. Five depression subtypes were found: somatic, cognitive, typical, severe and recovery with transitions occurring within rather than between subtypes. Typical subtype depression patients attended more sessions than somatic and cognitive subtypes. No significant differences were found between the three overarching depression subtypes regarding outcome nor acceptability. Unlike CBT, treatment outcomes in response to CfD appear to be comparable across subtypes. The results allow for clinically applicable insight in treating depression which includes evidence for subtyping based on routinely collected depression scores from new patients starting treatment. This could be used to classify patients according to their depression subtype and assign them to an intervention with the greatest likelihood of recovery. Furthermore, patients with depression subtypes that have an increased chance of dropout and lower chances of symptomatic improvement could be identified and prioritised for clinical supervision or more intense treatment.