Selective Mutism research findings

In 2013, iSpeak undertook research on Selective Mutism in adults entitled Selective Mutism in adults an exploratory study at the University of Chester. The main findings are presented below. NB: this summary of the research was created by Rosie from You can download the study here:

 Download PS7112_Dissertation (PDF) (2.2MB)

There is very limited research on adults with SM. Previous research mostly includes case studies of just one or two adults to show the rarity of the disorder, which we now know is not the case. Additionally, other than research from Victoria Roe (2011), there is very little out there which actually includes the first-hand experiences of those with SM and asks for their viewpoint rather than the professionals or researchers own opinion on the disorder. This is important because it is those with SM who can tell the most about the condition.

In 2013 selective mutism was included in the DSM V as an anxiety disorder for the first time and also mentions adults with SM, although it states that there hasn’t been any cross-sectional research on this area. ‘It is, therefore, an important time to do this current research in order to discern whether adults with SM perceive SM to be an anxiety disorder and, more simply, to confirm their existence.’

This research was an exploratory study of which the intended outcomes were as he describes below:

  • • To assert the existence of SM in adulthood, in order to challenge the perception that SM is solely a childhood "disorder".
  • • To investigate the varied ways that SM affects adults with SM, from the individual perspective of the sufferer themselves.
  • • To investigate the varied "reasons" that SM occurs.
  • • To investigate how adult sufferers of SM conceptualize SM.
  • • To investigate why SM did not dissipate for adults with SM who still have it.

83 adults took part in the study, all of whom had SM after the age of 18 and including 79 who still had selective mutism, who answered questionnaires which were posted on websites including and The questionnaires asked various questions including basic information (age, male/female, country) as well as more open ended questions about experiences, feelings and opinions on SM which many participants spent a long time answering, some providing their life stories for the study.

Below are the ten main hypothesis of the study and how the findings relate to them.

H1: SM is not solely a childhood disorder

The fact that anyone took part in the research in itself confirms that SM is definitely not solely a childhood disorder. All of the participants who took part had SM after the age of 18 and the majority were still living with the disorder.

The number of participants of course was limited to those who felt able to share their experiences. Selective mutism is an anxiety disorder affecting speech but often also affects written communication and the ability to express feelings. Writing and sharing personal experiences for those with SM could be difficult and there is likely to be many who could take part due to this. It also relies on the person with SM knowing about the websites where the study and questionnaires were posted; there could well be many, many more adults with SM who have not sought help on these websites or perhaps are not even aware of the condition they have. Carl writes that the 83 participants taking part in the study could just be the ‘tip of the iceberg’.

H2: SM occurs more frequently in adult females than adult males

In this particular study there were four times as many females as males which is higher than other studies on SM in childhood. Although this supports the hypothesis and suggests that in adulthood the gender ratio is a lot higher in females than males, there may be other reasons why this number is so high. For example, females may be more likely than males to sign up to health questionnaires and to share their feelings. Another interesting reason that Carl gave was the possibility of Aspergers’ Syndrome (AS); the number of participants in the study who had AS was lower than expected (only 3 in total) and as AS has been shown to be higher in males than females (4:1 male/female) it could be that males with both AS and SM are focusing on their AS in adulthood rather than seeking help for their SM separately. This would explain the lower than expected numbers of people with AS and the higher ratio of women to men overall in this particular study.

H3: The mean age of onset of SM will be before 4 years, based upon research on SM in children

This study showed the average onset of SM as 3.78. The latest age of onset was 16.

H4: Most sufferers of SM will not have received a formal diagnosis

In childhood, only around a quarter (26.3%) of participants received a diagnoses of SM. So for every person who was diagnosed with SM, there could well be many more with the disorder who have not received a formal diagnosis but have been affected by SM just as much.

H5: There will be high levels of co-morbidity in adults, particularly with other anxiety-related psychopathologies and eating disorders

Co-morbidity in the study included depression, anxiety, panic disorders and PTSD (post traumatic stress disorder) and the number of people with these disorders (based on self-reports) were higher than the expected would be in the general population. However, the link between eating disorders and SM was not as high as expected; 7 of the females reported having an eating disorder which was only one higher than the expected for the general population.

H6: The severity of SM will slowly reduce with age

On average, the highest severity of SM occurred between 12 and 19 years of age. Participants reported how severe their SM was through stages of their life and although the severity was higher than 50% from the ages of 5 to 34, it did slowly get lower from their 20’s towards a low level by around age 60 which shows that SM certainly does continue into adulthood and, for the majority, the severity of the SM does slowly reduce with age.

The average age of partial recovery (or ‘a turning point’) was 22, although there was one participant who was 46 and had no remission from SM. Participants were asked about the reason for partial recovery and most of these included some kind of change in their life; leaving education, starting a relationship, starting work, leaving home and having children. Some also mentioned forcing/challenging themselves to speak whereas others used therapy or medication. Alcohol was also mentioned which sometimes caused problems later in life.

H7: SM is not limited to school/educational settings

Rather than different situations, SM is often experienced when around certain people. Participants listed a number of examples such as with firstdegree and second-degree relatives, strangers, the opposite sex and professionals.

H8: SM is not a form of SAD, but is often co-morbid with/develops into SAD

Going against the hypothesis 72.3% of participants believed that SM is a form of social phobia and, up until the age of 12, had higher levels of social phobia than they did SM. However, this changes after the age of 12 when the levels of both social phobia and SM become very similar. Although the majority of those with SM believed it to be a form of social phobia, 27.7% (over a quarter) did not and saw SM to be separate to social anxiety.

From the open ended questions there were also thoughts and feelings which are often associated with SAD and anorexia nervosa such as feelings of undesirability or defectiveness, having very high standards, embarrassment and shame, and feelings of lack of entitlement.

H9: SM is the result of a G × E interaction, hence is partly genetic

From the study, most participants did not give a specific reason for having SM. There were seven mothers in the study who had children also with SM which may suggest that genetics or social learning could be a factor although more research would be needed to determine this.

Approximately a quarter of those in the study said abuse was a factor for their SM. However, it is worth noting that the NSPCC (2013) states that 25.3% of young adults say they were mistreated during childhood so this figure is not significantly higher than that of the general population.

Reasons for SM

From the research also came findings which were not related to the hypotheses, such as the participants perceived reasons for their SM. The top answer was shyness followed by no known reason and third was ‘a fear of what others think about me’.

Further research

Participants gave possible future research suggestions, two of which included how art depicts SM and if music, drama or art therapies are a way forward for SM. Other suggestions included: evaluating support for and accommodation of SM in the workplace, the physiological factors involved in SM and to evaluate the hereditary or social-learning aspects of SM further. Carl also gave possible future research including to evaluate the relationship between SM and eating disorders further, to look into the relationship between SM and safety behaviours, and to assess the text already received to evaluate further themes and express more thoroughly the individual experiences of those who experienced SM into adulthood.

Final note

As a final note, I’ll leave you with this graph of what participants thought could have helped them in childhood. More than three quarters answered with a ‘better understanding of SM in the school system’. So, what are we waiting for? Lets get those schools informed!


  •  Online questionnaire which had 83 participants all adults who had SM after the age of 18.
  •  Average onset of SM was 3.78 years (the latest onset in the study was 16).
  •  Around a quarter had received a formal diagnosis of SM.
  •  Co-mobidity with other anxiety and mood related disorders was significantly higher than that of the general population and included depression, social anxiety and PTSD.
  •  The severity of SM did generally reduce over time, the highest severity of SM was reported between the ages of 12 to 19.
  •  When asked what could have helped in childhood, over three quarters answered: better understanding of SM in the school system.

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